L.O 3.33: The student is able to use representations and appropriate models to describe features of a cell signaling pa

1. L.O 3.33: The student is able to use representations and appropriate models to describe features of a cell signaling pathway. SP 1.4: The student can use representations and models to analyze solutions or solve problems qualitatively and quantitatively. Explanation: In a cell there is a 3 stage process of cell signaling that occurs. First, reception occurs, which is when a ligand (a signal molecule) binds to a receptor that is membrane bound or inside the cell. There are 4 different types of receptors that a ligand can bind to depending on the specific communication that needs to take place: intracellular receptors or steroid hormone receptors, g-protein-linked receptors, tyrosine kinase receptors, and ligand-gated ion channels. Once the ligand has binded to the receptor the next process, transduction, occurs. Here, the conversion of the received signal to a cellular response takes place. This is mainly done by protein phosphorylations such as once a receptor is activated it phosphorylates protein kinases and other relay molecules (2nd messengers) within the cell, to aid in the signaling pathway to a cell response. Different proteins are activated through this process to help relay a particular cellular response. In the 3rd process, response, the transduced signal finally triggers a specific cellular response and this 3 stage process is repeated until the body is no longer in need of that response. An example of this signaling pathway is found commonly with hormones. When blood sugar levels rise in the body, the pancreas releases insulin, which then travels to the liver cells and binds to them. This signal into the liver cells creates a response to the store the sugar as glycogen thus dropping the blood sugar level back to normal allowing for homeostasis to be maintained within the body. Multiple Choice: The binding of a signaling molecule to which type of receptor leads to a change in distribution of ions on opposite sides of the membrane? a. tyrosine kinase receptor b.G protein-linked receptor c.phosphorylated tyrosine kinase receptor dimer d.ligand-gated ion channel e.intracellular receptor FRQ-style question: The relationship of structure to function is essential throughout biological topics. Specifically describe the Structure of a cell membrane and how signal transduction is related.

2. Answer Key- L.O. 3.33 • The binding of a signaling molecule to which type of receptor leads to a change in distribution of ions on opposite sides of the membrane? a. tyrosine kinase receptor b.G protein-linked receptor c.phosphorylated tyrosine kinase receptor dimer d.ligand-gated ion channel e.intracellular receptor • The relationship of structure to function is essential throughout biological topics. Specifically describe the structure of a cell membrane and how signal transduction is related. • The cell membrane is composed of a phospholipidbilayer that incorporates integral proteins. There are also membrane-bounded receptor molecules within the cell membrane to aid in the process of signal transduction. When a stimulus is present receptor proteins undergo shape changes as the signal is communicated through the membrane by shape change. The altered proteins then can have influence on other cellular processes as it could activate g-proteins or tyrosine-kinase receptor proteins phosphorylations thus creating a cellular response.

3. (a) Promoter (b) Enhancer SP 7.1: The student can connect phenomena and models across spatial and temporal scales. Albumin gene Control elements Explanation: Even though an individual’s cells have the same DNA sequences, each cell has different segments of DNA being expressed. Each segment codes for a different gene. In order to initiate transcription of a specific gene, polymerase binds to the DNA with the aid of transcription factors. These factors are important, because only once they have been assembled, can the polymerase begin producing a complimentary RNA strand. Enhancers are a transcription factor that may be located thousands of nucleotides away from a gene. A gene may have multiple enhancers that can be activated at different times, or in different cells types. An activator is a protein that binds to an enhancer and stimulates transcription of a gene. Some transcription factors are repressors, which inhibit gene expression by blocking the binding of activators. Activators and repressors can also act indirectly by influencing chromatin structure, such as attracting proteins that acetylate histones near promotors of genes, which leads to transcription. Transcription depends on the binding of activators to DNA control elements. There are only about a dozen nucleotide sequences that appear in control elements for different genes. Each enhancer is usually composed of about ten control elements, each of which bind to one transcription factor. Each combination of control elements in an enhancer associated with a gene is more important than the presence of a single unique control element. The specific transcription factors determine which genes are expressed in a cell. An example occurs between the liver cell and lens cell because both cells have genes for the proteins albumin and crystallin. However, the liver cell has specific activators that will bind to an enhancer that transcribes only the albumin gene; while the lens cell has different activators that match up with a different enhancer that leads to the expression of only the crystallin gene. Crystallin gene LO 3.18: The Student is able to describe the connection between the regulation of gene expression and observed differences between different kinds of organisms. Liver cell nucleus Lens cell nucleus Available activators Available activators • M.C. Question: Which of the following is NOT true when talking about how gene expression is regulated in a particular cell? • The activator that binds to a specific enhancer determines which genes will be transcribed. • The specific control elements within the enhancer are more important then the combination of control elements that an activator binds to. • An activator must first bind to an enhancer before general transcription factors such as RNA polymerase can bind to the promotor. • A repressor can bind to a separate enhancer which can terminate transcription even if activators are present. Learning Log/ FRQ-Style Question: Activators and repressors are both different types of proteins that can control gene expression. Tell what the role of each is and describe the how each of these can lead to the expression of a specific gene. Albumin gene not expressed Albumin gene expressed Crystallin gene not expressed Crystallin gene expressed Liver cell Lens cell

4. Distal control element 3 1 2 Activator proteins bind to distal control elements grouped as an enhancer in the DNA. This enhancer has three binding sites. ANSWER KEY LO-3.18 Promoter Activators Gene • Which of the following is NOT true when talking about how gene expression is regulated in a particular cell? • The activator that binds to a specific enhancer determines which genes will be transcribed. • The specific control elements within the enhancer are more important then the combination of control elements the an activator binds to. • An activator must first bind to an enhancer before general transcription factors such as RNA polymerase can bind to the promotor. • A repressor can bind to a separate enhancer which can terminate transcription even if activators are present. Activators and repressors are both different types of proteins that can control gene expression. Tell what the role of each is and describe how each of these can lead to the expression of a specific gene. Enhancer TATA box General transcription factors DNA-bending protein An activator is a protein that binds to an enhancer and will stimulate transcription. Activators are able to bind to distal control elements that are not close to the promotor. When an activator binds to an enhancer, protein-mediated bending of the DNA occurs. This allows the bound activators to come in contact with other transcription initiating proteins called mediator proteins. All these proteins together then interact with the promotor and allow for the binding of RNA polymerase II which initiates transcription of a particular gene. A repressor is a protein that inhibits the expression of a specific gene. One way a repressor can inhibit expression is by blocking activators from binding to control elements or to any proteins that are involved in transcription. Repressors can also bind directly to their own enhancer and can turn off transcription even in the presence of activators. A DNA-bending protein brings the bound activators closer to the promoter. Other transcription factors, mediator proteins, and RNA polymerase are nearby. Group of Mediator proteins RNA Polymerase II Chromatin changes The activators bind to certain general transcription factors and mediator proteins, helping them form an active transcription initiation complex on the promoter. Transcription RNA processing RNA Polymerase II mRNA degradation Translation Protein processing and degradation RNA synthesis Transcription Initiation complex

5. LO 4.3: The student is able to use models to predict and justify that changes in the subcomponents of a biological polymer affect the functionality of the molecule. • SP 6.1: The student can justify claims with evidence. • SP 6.4: The student can make claims and predictions about natural phenomena based on scientific theories and models. • Explanation: Changes in the monomers of a biological polymer affect its shape and therefore its function. The properties of each monomer are critically important to the function of the polymer.For example, the amino acids of a protein are categorized by how they react to water: hydrophilic or hydrophobic. They are also categorized by the type of bonds they form. Each amino acid has an R-group that determines its structure and thus its function. A notable example in this case are enzymes; enzymes are proteins that need to be a specific shape in order to properly conduct its biological activities. If an enzyme’s amino acids do not interact in a way that forms it into its specific “lock” shape, the enzyme will be rendered ineffective. A denatured enzyme is a “broken” enzyme that will not catalyze a substrate due to pH/temperature changes in the environment. These pH/temperature changes result in broken bonds in the amino acids, which change the shape in the primary, secondary, tertiary, or quaternary structures. Example M.C. Question: Which of the following properties allows a steroid to move into a cell and bind to a steroid receptor?A. steroids are polar, which allows them to bind to proteins in the membrane to diffuse through the cellular membrane.B. steroids are non-polar, which allows them to freely move through the phospholipid bilayer into the cell.C. steroids are saturated, so they bind to enzymes that break down a small part of the membrane and push the steroid through the membrane.D. steroids are unsaturated, so they move through ligand-gated ion channels. Example FRQ Question: Suppose you conduct an experiment in which you place Enzyme A into a test tube with its proper substrate. You place Enzyme B into a different test tube with its proper substrate as well. You measure the number of reactions in each test tube at 20 degrees Celsius for three minutes and record that 40 grams of product A was found in the first test tube. 43 grams of product B was found in the second test tube. You conduct a second experiment, raising the temperature to 40 degrees Celsius. You find that 38 grams of product A was found in the first test tube. 3 grams of product B was found in the second test tube. What can you conclude about the enzymes?

6. Which of the following properties allows a steroid to move into a cell and bind to a steroid receptor?A. steroids are polar, which allows them to bind to proteins in the membrane to diffuse through the cellular membrane.B. steroids are non-polar, which allows them to freely move through the phospholipid bilayer into the cell.C. steroids are saturated, so they bind to enzymes that break down a small part of the membrane and push the steroid through the membrane.D. steroids are unsaturated, so they move through ligand-gated ion channels. Explanation: Answer choice A is not correct because steroids are not polar. Answer choice C and D or not correct because the saturation/unsaturation of steroids do not affect whether or not the molecule can move through the phospholipid bilayer. Answer choice B is correct because non-polar substances that are a) accepted by the cell and b) small enough to move through the cellular membrane can freely move through the phospholipid bilayer, as the monomers of the steroid do not attract it to any other substance. • Example FRQ Question: • Suppose you conduct an experiment in which you place Enzyme A into a test tube with its proper substrate. You place Enzyme B into a different test tube with its proper substrate as well. You measure the number of reactions in each test tube at 20 degrees Celsius for three minutes and record that 40 grams of product A was found in the first test tube. 43 grams of product B was found in the second test tube. You conduct a second experiment, raising the temperature to 40 degrees Celsius. You find that 38 grams of product A was found in the first test tube. 3 grams of product B was found in the second test tube. What can you conclude about the enzymes? Explanation: Enzyme A and Enzyme B are both effective at catalyzing reactions at room temperature. However, enzyme A is still effective at catalyzing reactions at high temperatures, while enzyme B is not. Enzyme A must consist of amino acids with strong bonds that do not easily denature. The structure of enzyme A during the second experiment remained the same as the first experiment. This did not hold true for enzyme B; its amino acids did not maintain the same structure at a high temperature, because the rate of reaction was much lower. The amount of catalyzed substrate reflects that the shape of the substrate could not fit the shape of enzyme B during the second experiment, which obviously denatured. This experiment exemplifies that the shape of the enzyme plays a critical role in the reaction.

7. Explanation: Through his research, Mendel was able to determine that there are two different traits that can be expressed by an organism, which we call alleles. He called these alleles dominant and recessive. Mendel determined that every organism has two alleles, if an organism had two dominant alleles, it was known as homozygous dominant. If an organism had two recessive alleles, it was known as homozygous recessive. Mendel took his experiment farther when he crossed two true breeding flowers, one homozygous dominant and one homozygous recessive. What he noticed was that all the F1 generation all expressed the dominant allele but not all of the plants could be homozygous dominant because when you cross the two true breeding flowers, each of the progeny will have one dominant allele and one recessive allele. What Mendel determined was that an organism can express the dominant allele while also “carrying” the recessive allele, he called this discovery being heterozygous(Pp) for a trait. With this knowledge, Mendel was able to predict possible outcomes for the offspring of a particular generation. LO 3.14: The student is able to apply mathematical routines to determine Mendelian patterns of inheritance. Multiple Choice: Susan and Joe are going to have a child. Susan is a carrier of the sickle cell allele and Joe is homozygous dominant for the sickle cell allele. What is the probability that Susan and Joe will have a child with sickle cell? 1 c) ¼ 0 d) ½ SP 2.2:The student can apply mathematical routines to quantities that describe natural phenomena. FRQ: A new species of insect has been found on an island off the coast of South America. Scientists have concluded that black body is dominant to bronze body and normal wings are dominant to vestigial wings. Scientists crossed two insects, one homozygous dominant for black body, normal wings and one homozygous recessive for bronze body, vestigial wings. All the F1 offspring had black body, normal wings. Two F1 offspring were crossed and the information for the F2 offspring are as follows: 263 black body, normal wings, 233 bronze body, vestigial wings, 85 black body, vestigial wings, and 42 bronze body, normal wings. Find the recombination frequency of the F2 offspring using the recombination frequency formula, round to the nearest tenth and make sure to show your work. Also, using the recombination frequency, determine how many map units the recombinant genes are from each other, explain your answer. Using your knowledge of Mendelian patterns of inheritance, explain why the F1 offspring only expressed the two dominant traits while the F2 offspring expressed both the dominant and recessive traits.

8. Answer Key Slide Multiple Choice: Susan and Joe are going to have a child. Susan is a carrier of the sickle cell allele and Joe is homozygous dominant for the sickle cell allele. What is the probability that Susan and Joe will have a child with sickle cell? • 1 • 0 • ¼ • ½ FRQ: • RF= 127/623(100) RF=20.4% The recombinant genes will be 20.4 map units apart. We can determine this because one map unit is equal to 1% recombination frequency. b) The F1 offspring only express the two dominant traits because when you cross two true breeding insects as the parental generation are, the offspring obtain one copy of the dominant allele and one copy of the recessive allele for body color and one copy of the dominant allele and one copy of the recessive allele for wing shape. However, based on Mendelian patterns of inheritance, we know that the F1 progeny will be heterozygous, expressing the dominant allele gained from one parent while also being a carrier of the recessive allele. However, when we cross the two heterozygous F1 offspring, we know that because of Mendelian patterns of inheritance, there will be some organisms who will have to express the recessive traits based on scientific knowledge.

9. Learning Objective: 1.14 The student is able to pose scientific questions that correctly identify essential properties of shared, core life processes that provide insights into the history of life on Earth. Science Practice: 3.1 The student can engage in scientific questioning to extend thinking or to guide investigations within the context of the AP course.  3.1: Student can pose scientific questions. Explanation: The origin and history of life on Earth is constantly under debate. Organisms today share multiple core processes and features, this provides evidence that the complex organisms today could be derived from one common ancestor. The process of evolution explains how the incredibly diverse array of organisms could have originated from one universal ancestor. DNA and RNA carry genetic information in all organisms. These features of the genetic code can be found in all modern living systems. In eukaryotes, specifically, features like the cytoskeleton, membrane- bound organelles, a nucleus, endomembrane systems, and linear chromosomes are all core elements. Though evolution is widely viewed as a theory we lack an explanation of how these features could have been created separately or independently of one and other. The common core life processes found provide evidence that the history of life on Earth involves the evolution of complex and diverse live systems from one common or universal ancestor. Phylogenetic trees can help us visualize and estimate in what order species diverged from the common ancestor. Multiple Choice: All of the following factors provide evidence to support the theory that all living systems derive from one common ancestor EXCEPT: a. The universal existence of DNA and RNA in organisms. b. Membrane-bound organelles in eukaryotes. c. When life began the Earth was not stable enough to house more than one original common ancestor. d. Homologous structures found throughout multiple species. Free Response Question: a. Evolution from a common ancestor is said to explain the diverse and sometimes similar nature of Earth's species. Discuss two pieces of evidence that support this theory. b. Thinking in terms of this theory, if two species are structurally similar- are they more likely to have more recently shared a common ancestor or diverged from the ancestor longer ago?

10. Answer Key LO 1.14 Multiple Choice: All of the following factors provide reliable evidence to support the theory that all living systems derive from one common ancestor EXCEPT: a. The universal existence of DNA and RNA in organisms. b. Membrane-bound organelles in eukaryotes. c. When life began the Earth was not stable enough to house more than one original common ancestor. d. Homologous structures found throughout multiple species. Free Response Question: a. Evolution from a common ancestor is said to explain the diverse and sometimes similar nature of Earth's species. Discuss two pieces of evidence that support this theory. b. Thinking in terms of this theory, if two species are structurally similar- are they more likely to have more recently shared a common ancestor or diverged from the ancestor longer ago? a. Universal features found in eukaryotes like the cytoskeleton and membrane bound organelles support the theory that life came from one common ancestor. These traits are universal and it is likely that they were passed on through each generation from one shared relative. The fact that DNA and RNA are also used to carry genetic information in all living systems also supports this claim, because it is used in all life systems. b. If two species share a similar structure and homologous features, then it is more likely that they more recently shared a common ancestor. This way, there would be less time for the separate species to evolve different traits.

11. LO 2.31: The student can connect concepts in and across domains to show that timing and coordination of specific events are necessary for normal development in an organism and that these events are regulated multiple mechanisms. SP 7.2: The student can connect concepts in and across domains Explanation: In developing embryos, it is necessary for events to occur correctly by gene differentiation in order not to cause abnormalities in offspring. Once fertilized, the zygote replicates in to a clump of cells called a blastula. These cells have homeotic genes, which determine developmental patterns. The expression of certain genes lead to the development of different parts of the embryo. For example, Bicoid determines the posterior side of an embryo to determine where the head and feet go. From this point, a digestive tract is developed, called gastrulation. Morphogenesis plays the role of shaping parts of the body of the embryo such as the organs and appendages. Apoptosis, or programed cell death, aids in this development by killing cells that are unnecessary after certain checkpoints in development, such as formation of fingers and toes. M.C. Question: While testing gene expression, a early developing drosophila is injected with bicoid equally into both sides of the embryo. What result is most likely to occur? A) The drosophila will develop normally B) Apoptosis will occur to kill the extra bicoid cells and form both the head and tail of the embryo. C) The drosophila would develop two heads and die. D) Bicoid is not necessary in the development of drosophila. Learning Log/ FRQ- Style Question: While in the womb, human embryos develop webbing on their hands and feet as well as gills. In most cases, these features are not present in the offspring at time of birth. Why are these traits essential for the development timeline? What mechanism regulates the removal of webbing and gills and why is this important to the development of the embryo?

12. Answer Key- L.O. 2.31 While testing gene expression, a early developing drosophila is injected with bicoid equally into both sides of the embryo. What result is most likely to occur? A) The drosophila embryo will develop normally B) Apoptosis will occur to kill the extra bicoid cells and form both the head and tail of the embryo C) The drosophilaembryo would develop two heads and die D) Bicoid is not necessary in the development of drosophila embryo While in the womb, human embryos develop webbing on their hands and feet as well as gills. In most cases, these features are not present in the offspring at time of birth. Why are these traits essential for the development timeline? What mechanism regulates the removal of webbing and gills and why is this important to the development of the embryo? The formation of gills and webbing are important in development so that the embryo can survive in the aqueous environment of the mother’s womb. As the fetus approaches due date, lungs will begin to develop through morphogenesis. Apoptosis will then kill the webbing and gill cells. In the hands and feet, morphogenesis will aid the final formation of the fingers and toes. Around the neck, the gill slits will be fused together. If development does not continue correctly, a human baby can be born with webbing or non-functional gills, both of which will not affect their life drastically.

13. LO 1.13: The student is able to construct /or justify mathematical models, diagrams or simulations that represent processes of biological evolution. SP 1.1/2.1: (1.1)The student can create representations and models of natural or man made phenomena and systems in the domain. (2.1)The student can justify the selection of mathematical routine to solve problems. Explanation: In evolution phenotype expression is determined by the organisms combination of alleles for a certain genotype. A simple way of calculating the chance of a phenotype outcome/expression in a population is to use a Hardy-Weinberg equilibrium equation. The equation is p² + 2pq + q² = 1(as well as p+q=1). p represents the allelic frequency of dominant alleles in a population, while q represents the allelic frequency or recessive alleles, and pq is the heterozygous frequency. A Hardy-Weinberg test can be used to calculate such phenomena as a chance of a hereditary disease spreading in a population of organisms, as well as display this information in a model such as the picture in the bottom right. Another model that can be used to calculate the evolution of traits would be a punnett square. In epigenetics a punnett square is important in predicting the phenotype/genotype of a couples offspring. It can also be used to determine the biological evolution of a population depending on who they mate with. (Pictures below.) • M.C. Question: If a Colorblind male mates with a homozygous female who has a single • Barr body on one of her X chromosomes. What is the likelihood of their child having • colorblindness ? • A) 50% because colorblindness is only found in males • B) 25% if they are male and 0% if they are female. The Barr body in a female will not • Affect the crossing • C) 0% because colorblindness is recessive and the off spring would only have X^C Y • And X^C X^c • D)75% because the addition of the Barr body when it is activated could possibly result • In 3/4ths of the children expressing colorblindness . Learning Log/FRQ-style Question: Maria wants to have a child with Tyrone, but she is afraid that their child will get Hemophilia like her mother. Maria doesn’t express Hemophilia. She discovered that Tyrone’s grandmother on his moms side had hemophilia but his mom doesn’t.(his dads side has no history of it) What is the likelihood their child will have the disorder? Also explain your reason for this conclusion and include a punnett square and a pedigree.

14. ANSWER KEY– LO 1.13 If a Colorblind male mates with a homozygous female who has a single Barr body on one of her X chromosomes. What is the likelihood of their child having colorblindness ? A) 50% because colorblindness is only found in males B) 25% if they are male and 0% if they are female. The Barr body in a female will not Affect the crossing C) 0% because colorblindness is recessive and the off spring would only have X^C Y And X^C X^c D)75% because the addition of the Barr body when it is activated could possibly result In 3/4ths of the children expressing colorblindness . (side note: The fact it says Barr Body is meant to trick the student. All Females with XX Chromosomes only express one X and the other one is a Barr body) FRQ: Maria wants to have a child with Tyrone, but she is afraid that their child will get Hemophilia like her mother. Maria doesn’t express Hemophilia. She discovered that Tyrone’s grandmother on his moms side had hemophilia but his mom doesn’t.(his dads side has no history of it) What is the likelihood their child will have the disorder? Also explain your reason for this conclusion and include a punnett square and a pedigree. The likely hood of her child having hemophilia is about 25%. This is due to the fact that Tyrone’s mom being a carrier has no affect on his offspring because he does not have it and can not give it. But Maria being a carrier does affect the chance. Like in the sample drawing. The punnett square should resemble the one to the left. The pedigree should resemble the image in the top right. (sample drawing)

15. Learning Objective 3.11 : The student is able to evaluate evidence provided by data sets to support the claim that heritable information is passed from one generation to another generation through mitosis, or meiosis followed by fertilization. Connected Science Practice 5.3 : The student can evaluate the evidence provided by data sets in relation to a particular scientific question. Explanation: If a student is given a data set showing how a certain trait was passed on to the next generation, they should be able to read and understand the data and then use the information given to either answer questions or confirm/refute statements about whether or not heritable information was passed on through mitosis or meiosis and fertilization in a specific case. In order to do this, the student should have a good understanding of the process of mitosis and meiosis/fertilization, how genetic variation may or may not result from each one, and how that happens through processes like independent assortment, crossing over, mutations. etc. They should also be familiar with the haploid and diploid stages of mitosis/meiosis and have a good understanding of the cell cycle. For example, if the data set given, such as a punnett square, shows that a mother and father gave alleles to their children via sexual reproduction, the student would be able to assume that, since reproduction needed two haploid cells each with a different allele to join and produce a diploid zygote, meiosis, which results in four haploid cells, and fertilization occurred to produce the baby. If the data showed that the baby had the same DNA and therefore the same alleles and phenotypes as a single parent organism, the student should know that mitosis took place to pass on the genes of the parent and produce a clone. Biology Review PPT Slide Example Multiple Choice Question: Using the pedigree to the left, how can one tell that the autosomal recessive disorder was passed down through the generations via meiosis and fertilization rather then a behavior learned by offspring from their parents? A) All affected children have at least one parent who is also affected and unaffected couples have no affected offspring. B)Not all of the offspring in the second generation are affected even though both of their parents were affected. This can only happen because meiosis and fertilization produce four different gametes that can combine to form zygotes with different allele frequencies. C)The only homozygous recessive person is male meaning that the disorder is X-linked and therefore meiosis must be involved in passing the gene on to the next generation. D) There is no way to know this without further information. Example Essay Question: Using the data set to the left, explain how the pedigree would look different it mitosis were the process used for reproduction instead of meiosis and why.

16. Example Multiple Choice Question: Using the pedigree to the left, how can one tell that the autosomal recessive disorder was passed down through the generations via meiosis and fertilization rather then a behavior learned by offspring from their parents? A) All affected children have at least one parent who is also affected and unaffected couples have no affected offspring. B)Not all of the offspring in the second generation are affected even though both of their parents were affected. This can only happen because meiosis and fertilization produce four different gametes that can combine to form zygotes with different allele frequencies. C)The only homozygous recessive person is male meaning that the disorder is X-linked and therefore meiosis must be involved in passing the gene on to the next generation. D) There is no way to know this without further information. Example Essay Question: Using the data set to the left, explain how the pedigree would look different if mitosis were the process used for reproduction instead of meiosis. If the mitosis were the process used for reproduction instead of meiosis, then each offspring would only have one parent because mitosis is an asexual form of reproduction. Meiosis results in four, haploid, different daughter cells, that combine called a gamete with another gamete from the other parent to produce offspring with entirely unique genetic sequences. However, when a cell goes through mitosis, it first begins growing and replicating its DNA, the DNA winds into chromosomes and lines up single file while the nucleus disappears and other organelles are copied and split between two sides of the cell. Spindle fibers extend from each side of the cell and attach to centromeres in the middle of each chromosome. The chromosomes are torn in half and pulled to opposite ends of the cell, the nucleus reforms and the cell splits into two daughter cells. Each of these cells are clones of the parent cell. Leaving little room for genetic variation. So, in the pedigree, each of the offspring would be exact clones of their parent, so all of the individuals in the pedigree would have the same genotype and phenotype. The only way one could have a different genotype would be if that organism had a mutation in it’s DNA causing it to have a different trait then the others. This organism might then pass this trait on to its offspring and they would likely have it too because they would be clones of the cell with the mutation.

17. A) LO 4.17: The student is able to analyze data to identify how molecular interactions affect structure and function. B) SP 5.1: The student can analyze data to identify patterns or relationships. C) Carrying out a variety of functions in the body, proteins are complex macromolecules whose structure and function are determined by molecular interactions. Each protein has a unique shape and function that is determined by the different levels of structure. While all proteins have a primary, secondary, and tertiary structure, not all have a quaternary structure in which the protein is composed of more than one polypeptide chain. The primary structure of a protein is its own unique sequence of amino acids. It is then the secondary structure, in which the polypeptide is coiled/foiled into either an alpha helix or a beta pleated sheet depending on the hydrogen bonding within the polypeptide chain. The tertiary structure is the three-dimensional shape of the protein; it is then this three-dimensional shape that is superimposed on the protein’s secondary structure that determines the protein’s specificity. A protein’s resulting tertiary structure is influenced by factors such as the hydrogen bonding, ionic bonding, hydrophobic interactions, Van der Waals interactions, and disulfide bonds. Such factors determine how each polypeptide wraps around or bonds to itself to create a three-dimensional shape that is unique to that protein. The uniqueness of each protein is constricts to serve only its specified function within the body. Examples of unique proteins and their functions are in enzymatic activity and in transduction pathways. Enzymes are round(ish )proteins that exhibit tertiary structure. Each enzyme have its complementary substrate and will only bind to that complementary substrate; once an enzyme binds to its proper substrate, it is activated and catalyzes a reaction. In transduction pathways, the pathway is only initiated if the correct ligand binds to the substrate at the beginning of the pathway. • D) In an experiment, a protein is combined with a denaturing solvent that disrupts the molecular interactions that are holding it together. Once the protein is denatured, it losses its three-dimensional shape and becomes a flexible polypeptide chain. When the denaturing solvent is removed, the protein refolds itself into its original shape before being denatured. This experiment concludes that • a. the three-dimensional shape of a protein is determined by a denaturing solvent • b. the three-dimensional shape of a protein is based on its primary structure which consists of its amino acid sequence • c. the three-dimensional shape of a protein is completely randomized • the three-dimensional shape of a protein is unaffected by its primary and • secondary structures and is solely influenced by the its interactions with • outside elements A E) The following image depicts a portion of a polypeptide that is arranging itself into its tertiary structure through various molecular interactions. Identify each labeled interaction and determine how it affects the shape of the protein that is in the process of being formed. C B D

18. Answer Key LO: 4.17 • D) In an experiment, a protein is combined with a denaturing solvent that disrupts the molecular interactions that are holding it together. Once the protein is denatured, it losses its three-dimensional shape and becomes a flexible polypeptide chain. When the denaturing solvent is removed, the protein refolds itself into its original shape before being denatured. This experiment concludes that • a. the three-dimensional shape of a protein is determined by a denaturing solvent • b. the three-dimensional shape of a protein is based on its primary structure which consists of its amino acid sequence • c. the three-dimensional shape of a protein is completely randomized • the three-dimensional shape of a protein is unaffected by its primary and • secondary structures and is solely influenced by the its interactions with • outside elements E) The following image depicts a portion of a polypeptide that is arranging itself into its tertiary structure through various molecular interactions. Discuss the specific interactions at each labeled part. Point A exhibits hydrophobic and Van der Walls interactions. At such interactions, hydrophobic side chains cluster at the center of the protein so that they are as far away as possible from the water and other polar molecules that surround the protein. When non-polar amino acid side chains are within close proximity to one another, they are then held together by van der Waals interactions. Point B is an example of a hydrogen bond in which polar side chains are joined together. At point C two amino acid side chains are brought together by their sulfhydryl groups to form a disulfide bridge. At point D, portions of the polypeptide chain is brought together by an ionic bond formed between a positively charged side chain and a negatively charged one. A C B D

19. LO 1.12: The student is able to connect scientific evidence from many scientific discipline to support the modern concept of evolution. SP 7.1: The student can connect phenomena and models across spatial and temporal scales. The commonly supported Darwin view of evolution states that evolution is the change of gene frequencies in the gene pool of a population over many generations. This can happen when species are separated from one another (due to ecological or other barriers,) and the alleles offspring receive from the parents are mutated due to recombination and genetic variation. Natural selection then selects these favorable traits and due to “survival of the fittest” these organisms with the beneficial selected traits are able to reproduce and pass the trait on to their offspring. The change of allele frequencies though largely due to natural selection, can also be from isolation and restriction of gene flow between the parent and offspring resulting in divergent evolution. Examples of these forms of evolution can be seen in the molecular biology of DNA, comparative embryology, and the biogeography of fossils. Molecular evolution, has shown that all living organisms, ranging from bacteria to human, are related to common ancestors. The DNA coding sequences that transcribe proteins, and enzymes can be compared to other DNA sequences using DNA libraries to determine the last shared common ancestor. This can be used to determine both ancient relationships and recent ones. Comparative embryology proves evolution, because although many species look very different in adult form, most often have very similar embryos. These common embryos prove that all species shared common ancestors, because the serial structures are identical in the embryo, but specialized and diverged as an adult. The theory of evolution is also supported by biogeography. Identical plant and animal fossils have been located on opposite sides of the globe. This is due to the process of natural selection and illustrates both convergent and divergent evolution. Convergent evolution, where organism not closely related develop the same traits due to their environment, can be shown by the fossils of sugar gliders and flying squirrels, that are on opposite continents, but due to natural selection and genetic mutation evolved with the same traits. Divergent evolution can also be proved by fossils and is shown in humans, horses, cats, and birds that all shared a common ancestor because they all have the same arm bones. Multiple Choice: Structures that are as different as human arms, whale flippers, and horse legs have been found to have many similar bones that developed from very similar embryonic tissues. How can it be proved these structures are related? A) Using the definition of homologous structures B) Because of convergent evolution C) Because humans, whales, and horses share a common ancestor D) All of the above E) A and C are correct Essential Question: Evolution as defined by Darwin is the change of gene pool frequencies in a gene pool over many generations. Choose and explain THREE ways scientist can prove and support this idea.

20. ANSWER KEY- LO 1.12 Structures from organisms as different as human arms, whale flippers, and horse legs have many similar bones that developed from very similar embryonic tissues. How can it be supported/ proved these structures are related? A) by identifying the bones as being homologous structures B) by the principle of convergent evolution C) by proposing that humans, bats, and dolphins share a common ancestor D) All of the above E) A and C are correct Evolution as defined by Darwin is the change of gene pool frequencies in a gene pool over many generations. Choose and explain THREE ways scientist can prove and support this idea. Scientists can support this idea using the three scientific disciplines: embryology, biogeography of fossils, and the molecular biology of DNA. In the embryo the serial structures of almost all organisms are nearly identical, which cannot be said once they have developed as adults. Using comparative embryology, the similarity in structure supports the idea that they share a common ancestor, and developed through evolution. The biogeography of fossils can be used to support the idea of convergent evolution. For species like the flying squirrel and sugar gliders, though they live on separate continents due to genetic mutations, and similar ecosystem pressures they have adapted similar structures. By comparing their fossils, scientists can pinpoint these genetic mutations and track the evolution of the species. The molecular biology of DNA, shows the closely related base sequences of many organisms. These similar nucleotide sequences identify common ancestors, which can easily be located using genomic libraries, as scientists can compare and evaluate the evolution of species from these common ancestors.

21. LO 2.10 The student is able to use representations and models to pose scientific questions about the properties of cell membranes and selective permeability based on molecular structure. [See SP 1.4, 3.1] • SP 1.4 The student can use representations and models to analyze situations or solve problems qualitatively and quantitatively. SP 3.1 The student can pose scientific questions. • Explanation • Cell membranes are important for cell life and activity because they regulate transport across cellular boundaries. For instance, cells take in oxygen to use for cellular respiration and then release carbon dioxide. Cell membranes are selectively permeable, meaning that they allow some substances to cross more easily than others. The cell membrane is made primarily of lipids and proteins. The greatest amount of lipids are phospholipids, which make the phospholipid bilayer. Phospholipids are amphipathic molecules, meaning that they have a hydrophilic (polar) head which is exposed to the aqueous solution on either side of the membrane, and a hydrophobic (nonpolar) tail which is contained in the middle of the bilayer. The exterior proteins, parts of proteins, and carbohydrate side chains are also polar while inner proteins are nonpolar. The dispersal of proteins in the phospholipid bilayer is known as the fluid mosaic model for membranes. Hydrophobic (nonpolar) molecules, such as hydrocarbons, carbon dioxide, and oxygen, can cross the membrane with ease through the process of diffusion. However, hydrophilic (polar) molecules, such as glucose, other sugars, and even water, have a difficult time diffusing through the hydrophobic (nonpolar) core of the membrane. These molecules cannot cross the membrane as rapidly as nonpolar molecules. The membrane is even more difficult to pass through for charged atoms or molecules. In order for these ions and other polar molecules to pass through the membrane, they must pass through a transport protein that has a polar channel that the ions and polar molecules use as a tunnel to enter the cell. For instance, the passage of water into and out of a cell is made possible by channel proteins called aquaporins. Also carrier proteins aid in diffusing polar molecules into the cell. The use of channel proteins or carrier proteins or the simple diffusion of nonpolar substances across the plasma membrane is known as passive transport. Passive transport occurs when molecules move down their concentration gradient (from high concentration to low concentration). • Multiple Choice Question • In a eukaryotic cell, which of the following • molecules would require the use of a channel protein • in order to enter the cell? • A. Hydrocarbon • B. Sucrose • C. Iodine • D. Estrogen • Free Response Question • Certain properties of cell membranes make them permeable to some molecules • while impermeable to others. Explain the cell membrane structure and • chemical properties that allow for this discrepancy. Provide an example of a • molecule that would and a molecule that would not be able to permeate a cell • membrane based on the chemical properties you described above. Facilitated diffusion Diffusion Passive transport WATER Hydrophilic head Hydrophobic tail WATER

22. Multiple Choice Question • In a eukaryotic cell, which of the following • molecules would require the use of a channel protein • in order to enter the cell? • A. Hydrocarbon • B. Sucrose • C. Iodine • D. Estrogen • Multiple Choice Answer: • B. Sucrose. • The three other answer choices (hydrocarbon, iodine, and estrogen) are nonpolar molecules so they would be able to use simple diffusion to permeate the cell membrane. Sucrose, a sugar, is polar, thus requiring a channel protein to permeate the cell membrane. • Free Response Question • Certain properties of cell membranes make them permeable to some molecules • while impermeable to others. Explain the cell membrane structure and • chemical properties that allow for this discrepancy. Provide an example of a • molecule that would and a molecule that would not be able to permeate a cell • membrane based on the chemical properties you described above. • FRQ Model Answer: • Cell membranes are made of phospholipids (1). A unique chemical property of phospholipids is their polar head, which is exposed to the interior and exterior of the cell, and their nonpolar tail, which is in the interior of the membrane (1). These chemical properties make it easy for nonpolar molecules to diffuse through the cell membrane(1). However, the nonpolar core makes it difficult for polar molecules to diffuse through the membrane(1). An example of a nonpolar molecule that can use simple diffusion to pass through the cell membrane is oxygen (1). An example of a polar molecule that would require the use of a channel protein through facilitated diffusion to pass through the cell membrane is water (1).

23. LO 1.31 The student is able to evaluate the accuracy and legitimacy of data to answer scientific questions about the origin of life on Earth. • SP 4.4 The student can evaluate sources of data to answer a particular scientific question. • Explanation: When scientist consider the conditions that led to the organic compounds that evolved to the different facets of life that we know today, there are many experiments that scientist have done to simulate the conditions that were in early earth se see if they can create organic compounds.One hypothesis came in the 1920’s from Oparin and Haldane thinking that earth’s early atmosphere had been a reducing atmosphere (electron-adding) which organic compounds could have formed with lightning. The early oceans had a solution of molecules(Primitive Soup). Then in 1953 and experiment was done with Miller and Urey to test the Oparin-Haldane hypothesis in which they set up a closed system which had a flask of warmed water (to represent the warm sea).This then became water vapor and met another flask(the reducing atmosphere) which had hydrogen, methane and ammonia which were abundant in early earth. Then sparks were put into the flask(lightning). When this simulation was repeated a lot they found basic organic compound in the water such as amino acids. It was later seen that only very small pockets had this reducing atmosphere. They think that it was more likely produced in hydrothermal vent deep in the ocean. These are the two theories that scientist believe how life was created. • M.C. Question • Free response question • a. Considering the Oparin-Haldane hypothesis what experiment was run that supported this hypothesis? b.Explain what these experiment proved? c. What type of early compounds were made out of this experiment? d. What 3 steps are needed to go from an early organic compound to a complex cell. In Miller and Urey’s experiment which of the following products was NOT formed. A lipids B living cells C Phenylalanine D Pyrimindines E ATP(with Phosphate)

24. Answer key-LO 1.31 • In Miller and Urey’s experiment which of the following products was NOT formed • A lipids • B living cells • C Phenylalanine • D Pyrimindines • E ATP(with Phosphate) • a. Considering the Oparin-Haldane hypothesis what experiment was run that supported this hypothesis? • b.Explain what these experiment proved? • c. What type of early compounds were made out of this experiment? • d. What 3 steps are needed to go from an early organic compound to a complex cell. • A. The experiment that was used to prove the Oparin-Haldane hypothesis was the experiment that was done by Miller and Urey. Which was done in a closed flask using water vapor, electrodes, and hydrogen, methane and ammonia. • B. This experiment proved that some of the basic building blocks of life, like amino acids would have been made in the early earth reducing atmosphere. • C. In the Miller and Urey’s experiment many different products were made. When this simulation was repeated a lot they found that all 20 amino acids were formed, several sugars, lipids were made, Purines and Pyrimindines, ATP ( after phosphate is added) and every single monomer was made. • D. The three steps that are needed to go from an early compound to a complex cell. The first step is a lipid bilayer of a plasma membrane need to form this can form from lipids in water. The next step is the need for genetic information(DNA) this information is important because it includes the instructions to replicate themselves. They third step is the inclusion of organelles. This could have happened through serial endosymbiosis. This is where a Ancestral prokaryote which had a plasma membrane and DNA (step 1 and 2) engulfed a small aerobic heterotrophic prokaryote which was Mitochondrion. Which became the heterotrophic eukaryote or the same Large prokaryote engulfed a photosynthetic prokaryote which now has mitochondrion and plastid, so now this cell is an ancestral photosynthetic eukaryote. These are now complex cells.

25. 1) LO 4.20 The student is able to explain how the distribution of ecosystems changes over time by identifying large-scale events that have resulted in these changes in the past. • 2) SP 6.3: The student can articulate the reasons that scientific explanations and theories are refined or replaced. • 3) Ecological succession is the observed process of change in the species structure of an ecological community over time. Meaning as the environment of an ecosystem begins to change so will the the plants and animals living in it and this process is known as succession. There are two main types of Succession. Primary Succession and Secondary Session. Primary Succession occurs over a long period of time after a large-scale event in an area where there is little vegetation, poor soil quality and hard living environment after the event. In other words Primary Succession is the beginning of that ecosystem and follows the changes in it over time. Events that could cause primary succession are Volcanoes and Ice Ages. When Volcanoes erupt the lava can flow into the ocean and hardens in to new land. This new strip of land can then be colonized by Pioneer species, slowly growing over time Intermediate species will take hold until the final Climax Community emerges. This process is aided by the weathering and break up of the lava and organic debris through the air being deposited onto the new land. Ice Ages can also cause primary succession to occur. As the World gets colder and glacier begin to form and creep down or up towards the equator the ice cuts through the soil and rock in its path. As the Ice age ends like the one 10,000 years ago did the glaciers retreat and cut out large canyons and rivers, like the Colorado River and Grand Canyon. Secondary succession is a process started by an event, such as a forest fire or hurricane, that reduces an already established ecosystem to a smaller population of species without completely destroying the ecosystem. In other words secondary succession is when a healthy ecosystem has a hurricane or forest fire or some other short term event damage part of the ecosystem and it has to repair itself. This is known as secondary succession. Scientific Theories can act much like Ecological Succession. A theory can be thought of by the world as completely accurate, but then new information or a new discovery can cause parts of this completely accurate theory to be wrong, so it is refined or replaced with a new one. When the Theory is replaced it acts like Primary Succession and the theory starts from scratch, where as when the theory is refined it is more like Secondary Succession and has a new piece of information added to it and is refined. • 4) Multiple Choice Question: Which of the following Events could result in Primary Succession? • a) Forest Fire b) Glacier c) Earthquake d) Flood • 5) Free Response Question: • a. Explain the differences between Primary Succession and Secondary Succession • b. Give an example of a large scale event that could cause primary succession to occur, and explain what would take place following the event to allow for the development of an ecosystem.

26. Answer Key 4) Multiple Choice Question: Which of the following Events could result in Primary Succession? a) Forest Fire b) Glacier c) Earthquake d) Flood FRQ) a. Primary Succession occurs over a long period of time after a large-scale event in an area where there is little vegetation, poor soil quality and hard living environment after the event. In other words Primary Succession is the beginning of that ecosystem and follows the changes in it over time. Events that could cause primary succession are Volcanoes and Ice Ages. Secondary succession is a process started by an event, such as a forest fire or hurricane, that reduces an already established ecosystem to a smaller population of species without completely destroying the ecosystem. In other words secondary succession is when a healthy ecosystem has a hurricane or forest fire or some other short term event damage part of the ecosystem and it has to repair itself. So the main difference between the two is Primary succession occurs at the beginning of an ecosystem and Secondary Succession occurs in an already developed ecosystem. b. A volcanic eruption could cause primary succession to occur. When the volcano erupts molten lava flows out of the volcano and onto land or water and hardens creating a new land mass. This new land mass over time will have lichen spores carried by the wind land on the bare rock face. These lichen will release acids that help break down the bare rock into a base soil layer and as the lichen die they will release some basic nutrients into this new soil layer. Airborne spores from mosses and ferns will then land on the new base soil layer and will begin to grow. These mosses and ferns will help further break up the soil and make it thicker. As they die they will release even more nutrients into the soil and water will now be able to be held by the soil. Pioneer species of plants and animals will begin to settle on this new developing ecosystem. As the pioneer species take hold Intermediate species will move in as well. Once both the Pioneer and Intermediate species develop and help the ecosystem a few more species will come and the ecosystem now after many years will be a climax community.

27. LO 2.11: The student is able to construct models that connect the movement of molecules across membranes with membrane structure and function. SP 1.1: The student can create representations and models of natural or man-made phenomena and systems in the domain SP 7.1: The student can connect phenomena and models across spatial and temporal scales SP 7.2: The student can connect concepts in and across domain(s) to generalize or extrapolate in and/or across enduring understandings and/or big ideas Explanation: Membranes are generally made up of phospholipids and embedded proteins. The phospholipids make up a fluid bilayer that is hydrophilic on the outside and hydrophobic on the inside. The fluidity is maintained by cholesterol amongst the lipids. The hydrophobic center allows for free movement of nonpolar molecules and some small polar molecules, while it is impermeable to large polar molecules and ions. Proteins, including channel proteins and carrier proteins, are imbedded into the membrane amongst the phospholipids, and provide pathways across the membrane for molecules specific to the properties of the protein. For instance, aquaporin proteins allow for rapid movement of water molecules through the membrane because of the hydrophilic properties of its channel. Others of these proteins can use ATP to undergo active transport, which moves molecules through a membrane against the concentration gradient. Endocytosis and exocytosis can also occur because the phospholipids are able to create smaller pockets, called vesicles, to hold molecules inside them for transport into and out of the cell. All of these structures and functions play a role in the semi-permeability of a membrane. Multiple Choice: Which of the following statements concerning movement of molecules is false? Carrier proteins change their shape to transport molecules. Water moves through the phospholipid bilayer. The “walls” of vesicles are a phospholipid bilayer. Permeability of the bilayer decreases at low temperatures. FRQ-style Question: What do you expect would occur if a dehydrated cell is placed in an aqueous environment? What processes would occur, for what reason, and how?

28. Answer Key: LO 2.11 Multiple Choice: Which of the following statements concerning movement of molecules is false? Carrier proteins change their shape to transport molecules. Water moves through the phospholipid bilayer. The “walls” of vesicles are a phospholipid bilayer. Permeability of the bilayer decreases at low temperatures. FRQ-style Question: What do you expect would occur if a dehydrated cell is placed in an aqueous environment? What processes would occur, for what reason, and how? If a dehydrated cell is placed in an aqueous environment, the process of osmosis would occur in order to achieve equilibrium on the inside and the outside of the cell. Water would flow from the water-rich environment into the water-deficient cell at a faster rate than the water will flow from the cell to the environment. Water could flow through both the phospholipid bilayer of the cell at a relatively slow rate to achieve equilibrium. Because the center of the phospholipid bilayer is hydrophobic, however, it will resist the passage of water and slow the flow down. The water could also use the channel proteins called aquaporins in order to undergo osmosis much faster. Because the channels of aquaporins have hydrophilic traits, water is capable of movement through the channels much more efficiently than through the phospholipid bilayer. A combination of these methods of osmosis would occur in this situation in order to achieve equilibrium, at which point water will flow in and out of the cell at the same rate, using the same methods once again.

29. LO 3.20: The student is able to explain how the regulation of gene expression is essential for the processes and structures that support efficient cell function. SP 6.2: The student can construct explanations of phenomena based on evidence produced through scientific practices. Explanation: Within an organism, all somatic cells contain the same DNA, as they are all descended via mitosis from the original zygote. Cells found in different parts of an organism, however, may display drastically different characteristics. This is due to different models of gene expression between the cells. Organisms begin to show cell differentiation, or differences in structures between cells, starting after only a couple of divisions. Different levels of certain proteins within a cell affect how that cell expresses its genes, and these differences can be found as early as the four-cell stage. Promoters are proteins that bind to sections of DNA to increase transcription of the nearby gene, while repressors decrease transcription. In addition to promoters and repressors, intron splicing can remove certain parts of RNA after transcription to leave the desired codons. The first instance of differentiation is the determination of anterior and posterior sections, and as the organism grows and finds its shape, more specific differentiation occurs. The many types of tissues in complex organisms each exhibit their own characteristics as a result of gene regulation. Within a cell, genetic regulation also allows the cell to synthesize different proteins based on messages the cell receives from its environment or other cells. Hereditary causes of gene regulation are passed on through epigenetic inheritance, which is passing down of genetic information that is not coded for in the nucleotide sequence. Gene regulation can also be controlled by environmental factors such as exposure to sunlight or heat. Regulation of gene expression is important for complex organisms because of the various tasks that they must perform. To accomplish these tasks, an equally varied set of cells is necessary. For example, a human nerve cell is dramatically different from a muscle cell. At first glance, the two cells may appear to be from different organisms. Upon closer examination, however, the two cells contain the same DNA. The differences in the proteins and structures of the cells are due to gene regulation and are the reason that both cells can work to perform different jobs for the survival of the human. Multiple Choice: Which of the following best exemplifies how the regulation of gene expression allows cells to adapt to their environments? a) A certain protein is found primarily on one side of a human zygote. b) Daniel’s mother and father both have brown eyes, but Daniel’s eyes are blue. c) Bobby’s skin cells translate more of a certain protein after a long day in the sun. d) Sami grew steadily until the age of eight, then stopped getting taller Free Response: A scientist is examining cells from a drosophila and notices that some cells have a high number of proteins used in the synthesis of mitochondria, while other cells contain many proteins for ion channels and pumps. i) What are two possible causes of the disparity in the protein frequencies between the two types of cells? ii) What advantages do the two types of cells have in terms of life processes? iii) What two types of body cells are the scientist likely studying?

30. LO 3.20: The student is able to explain how the regulation of gene expression is essential for the processes and structures that support efficient cell function. SP 6.2: The student can construct explanations of phenomena based on evidence produced through scientific practices. Answer Key Multiple Choice: Which of the following best exemplifies how the regulation of gene expression allows cells to adapt to their environments? a) A certain protein is found primarily on one side of a human zygote. b) Daniel’s mother and father both have brown eyes, but Daniel’s eyes are blue. c) Bobby’s skin cells translate more of a certain protein after a long day in the sun. d) Sami grew steadily until the age of eight, then stopped getting taller Free Response: A scientist is examining cells from a drosophila and notices that some cells have a high number of proteins used in the synthesis of mitochondria, while other cells contain many proteins for ion channels and pumps. i) What are two possible causes of the disparity in the protein frequencies between the two types of cells? ii) What advantages do the two types of cells have over each other in terms of performing life processes? iii) What two types of body cells are the scientist likely studying? The different protein frequencies in the two cells are a result of different gene expression. Cytoplasmic determinants may have promoted the transcription of mitochondrial proteins in the first cell type while repressing transcription of proteins used in ion channels and pumps. In the second type, the opposite may be true. The gene expressions could also have resulted from the cells’ environments. Ligands could have been sent to neighboring cells of a stimulus, eventually telling the nucleus to produce more proteins for mitochondrial proteins. The first cell type is ready to synthesize many mitochondria, where cellular respiration produces ATP. This means it has an advantage in energy production over the second cell type. The second type will build many ion channels and pumps. These will allow it to alter the concentration of certain ions within its cytoplasm and outside of the cell, which will help with intercellular communication. The first cell type is most likely a muscle cell. Muscle cells do much of the physical work in an organism, so they need a higher amount of ATP than other cells to power this work. The second cell type is probably a nerve cell. Nerve cells have to communicate effectively with each other, and they use differing ion concentrations to achieve this communication. Diagram source: Howard, Gadi. "Shedding Light on Blindness." The Future Of Things Science and Technology of Tomorrow. N.p., 4 Sept. 2007. Web. 01 May 2014. <http:// thefutureofthings.com/3079-shedding-light-on-blindness/>.

31. LO 2.1 The student is able to explain how biological systems use free energy based on empirical data that all organisms require constant energy input to maintain organization, to grow and to reproduce. SP 6.2 The student can construct explanations of phenomena based on evidence produced through scientific practices. Explanation: Free energy for organisms is provided by the molecule ATP, or adenosine triphosphate. ATP has three phosphorus molecules connected by phosphate bonds. When the bond between two of the three phosphate molecules is broken by hydrolysis, which is the splitting of something, the organism is left with adenosine diphosphate (containing two phosphorus molecules), a free phosphorus molecule, and free energy that has been released by the breaking of the bond between the phosphorus molecules. A negative change in free energy indicates an increase in free energy. Free energy is also involved in the regulation of an organism’s body temperature. Endotherms use energy they have produced to regulate their body temperature. Ectotherms use external energy to regulate their body temperature. Also, keep in mind that there is a relationship between the metabolic rate of an organism and their size. A smaller organism will have a higher metabolic rate, or use energy quicker. In addition to the amounts of free energy needed for the organism to maintain homeostasis and grow, they need even more energy to regulate their reproductive cycles and produce viable offspring. If an organism does not have a sufficient amount of free energy to regulate their essential functions, they will eventually not be able to perform these functions anymore and will die. ATP provides energy for the three types of cellular work: mechanical, transport, and chemical. In the instance of mechanical work, it helps to perform tasks such as moving motor proteins by transferring a phosphate group to the motor protein. Motor proteins help move organelles and proteins inside a cell, which lets the cell continue to function and maintain homeostasis. In transport cellular work, the best known example is active transport. This is when solutes move against the cell’s concentration gradient, but require some sort of force to do it. ATP provides a phosphate group, which phosphorylates the carrier protein imbedded in the cell membrane. Phosphorylation of this protein changes the conformation of the cell, which basically means it makes the protein pump against the concentration gradient. When the phosphate group detaches from the carrier protein, it goes back to its original conformation. Plants employ active transport when they absorb salts that are diluted in the soil by moving the salt against the concentration gradient. Since organisms need free energy to maintain their essential functions, they use a source of ATP to phosphorylate other molecules and proteins in order to do cellular work. This cellular work results in maintenance of homeostasis in the organism. • Multiple Choice: • Which of the following is NOT true of ATP being used to do cell work? • It phosphorylates a carrier protein to pump molecules through a plasma membrane from a high solute concentration to a low solute concentration. • Once ATP is broken into ADP and a phosphate group, it rebonds using excess free energy. • Plant cells depend on ATP made from the light reaction cycle to power the Calvin Cycle. • An exergonic reaction absorbs free energy and therefore results in a negative ▲G. Free Response Question: An animal cell cannot produce any of its own free energy. ATP is being synthesized, but not utilized. What is the cause of the lack of free energy in the animal cell? What would happen if the problem was fixed? Draw a diagram of the product of your solution.

32. Multiple Choice Answer and Explanation: Correct Answer: D An exergonic reaction results in excess free energy. An endergonic reaction is the type of reaction that absorbs free energy. When there is a release of free energy from a reaction, the change in G, or ▲G, becomes negative. Free Response Answer and Explanation: In order for ATP to phosphorylate other molecules, it must first be hydrolyzed. Assuming the ATP is being produced and is fully functional, the problem is that the cell is not hydrolyzing the ATP to split it into ADP and a phosphate group. This most likely means that the cell does not have any H20 with which to hydrolyze the ATP. The solution to this problem is to simply provide the animal cell with an amount of water, enough to suffice for hydrolysis and other necessary cell functions, but not too much as to burst and kill the cell. If the amount of water is sufficient, the cell will finally begin to hydrolyze ATP and phosphorylate the necessary proteins and molecules as well as producing free energy. This will regulate cell functions and allow the cell to do work in order to maintain homeostasis. The cell will begin to grow and reproduce again, improving the overall health of the organism. This is what normal ATP hydrolysis looks like. If the problem in the animal cell was fixed, this is what would continue to happen again. ATP would hydrolyze into ADP and a phosphate group, releasing free energy in the process.

33. LO 3.46 The student is able to describe how the vertebrate brain integrates information to produce a response. • SP 1.2 The student can describe representations and models of natural or man-made phenomena and systems in the domain • Explanation : The body will first recieve a sensory input. Sensory neurons will transmit information from sensory organs. The stimuli can be either external (light, sound, taste, touch, heat, and smell) or, internal ( blood pressure, CO2 levels or muscle tension). This sensory input is then sent up the spinal cord to the central nervous system. Interneurons analyze and intepret this input by reviewing the past and immediate details. Sensory neurons then communicate with motor neurons that produces the motor output. The motor neurons then interact with effector cells (muscle cells or endocrine cells) to produce a response to the sensory stimuli. Very simple and automatic responses are known as reflexes. • Multiple Choice Question : What is the purpose purpose of ganglia ( a cluster of neurons segmentally arranged) in invertebrates and insects ? A) To allow faster responses between the sensory organs to the spine • B) To connect the CNS with the rest of the animals body ; makes up the peripheral nervous system • C) Helps the CNS neurons interpret signals • D) Supporting cells essential for structual purposes • Learning Log/FRQ-style Question : • Suppose you have a patient whom you are testing in a routine physical. When you test their knee reflex there is no response. Explain the processs of how sensory input is processed and possibilities of why you saw no response from the stimuli.

34. Answer Key- LO 3.46 • Multiple Choice Question : What is the purpose purpose of ganglia ( a cluster of neurons segmentally arranged) in invertebrates and insects ? • A) To allow faster responses between the sensory organs to the spine • B) To connect the CNS with the rest of the animals body ; makes up the peripheral nervous system • C) Helps the CNS neurons interpret signals • D) Supporting cells essential for structual purposes • FRQ- • Suppose you have a patient whom you are testing in a routine physical. When you test their knee reflex there is no response.Explain the processs of how sensory input is processed and possibilities of why your patient showed no response from the stimuli. • The reflex is stimulated when tapped on the tendon in the quadriceps muscle. Sensors pick up a stimuli by the stretch in the quadriceps. Sensory neurons then send this sensory input tothe spinal cord. Sensory and motor neurons communicate with one another. Motor neurons send signals to the quadriceps to cause them to contract. Whilst this is happening sensory neurons are also communicating with interneurons in the spinal cord. These interneurons will inhibit motor neurons causing the hamstring to not contract. One reason could be a spinal injury because the motor and sensory neurons can't communicate the sensory input to produce the motor output within the spine causing no reaction to happen.

35. LO 3.43:The student is able to construct an explanation, based on scientific theories and models, about how nervous systems detect external and internal signals, transmit and integrate information, and produce responses. SP 6.2: The student can construct explanations of phenomena based on evidence produced through scientific practices. SP 7.1: The student can connect phenomena and models across spatial and temporal scales. Explanation: The nervous system can be broken down into two parts: the central nervous system (CNS) which consists only of the nerves protected by bone (the brain and spinal cord) and the peripheral nervous system (PNS) which consists of all other nerves throughout the body. Sensory neurons are responsible for detecting internal conditions like blood pressure, blood CO2 levels, and muscle tension as well as external stimuli such as light, sound, touch, heat, smell, and taste. The information is then transmitted to the CNS where interneurons analyze and interpret stimuli. Motor neurons send signals to effector cells in muscles or endocrine glands which produce a response. A neuron has two extensions arising from the cell body. The dendrites are branched extensions that receive signals from other nerves cells while the axon is a much longer extension that sends signals away from the cell body. The axon is covered by sections of myelin sheath that are separated by a small gaps called nodes of Ranvier. The myelin sheath allows for signals to “jump” from section to section of the axon for much faster travel. Once the signal is transmitted from the axon hillock to the terminal branches of the axon (signal only travels in one direction!), a neurotransmitter is released across the synapse to the dendrites of another neuron. The signal is converted from chemical (when received by dendrites) to electrical when traveling to cell body and through axon and back to chemical as the neurotransmitter is released across the synapse. M.C Question: How would nerve impulse transmission be affected if the myelin sheath on the axon were to deteriorate? A.) The speed of transmission would stay the same since the impulse travels down the axon on the inside of the myelin sheath B.) The speed of the impulse would decrease drastically and would result in symptoms similar to multiple sclerosis C.) The “all or none response” would cause the neuron not to fire at all. D.) The speed of the impulse would increase since the myelin sheath can no longer slow it down. Free Response Question: You are fishing for Asian Carp at Lake Michigan doing your job to reduce the number of invasive species in the environment. The carp did not look favorably upon your actions and decided to attack you by flying out of the water and clutching onto your arm with its mouth. Describe the process behind how you were able to react to this odd situation.

36. M.C Question: How would nerve impulse transmission be affected if the myelin sheath on the axon were to deteriorate? A.) The speed of transmission would stay the same since the impulse travels down the axon on the inside of the myelin sheath B.) The speed of the impulse would decrease drastically and would result in symptoms similar to multiple sclerosis C.) The “all or none response” would cause the neuron not to fire at all. D.) The speed of the impulse would increase since the myelin sheath can no longer slow it down. Free Response Question:You are fishing for Asian Carp at Lake Michigan doing your job to reduce the number of invasive species in the environment. The carp did not look favorably upon your actions and decided to attack you by flying out of the water and clutching onto your arm with its mouth. Describe the process behind how you were able to react to this odd situation. As the carp latched onto my arm, the sensory neurons in my arm detected the stimuli. The neuron became depolarized at the axon hillock and a nerve impulse was sent down the axon. The myelin sheath helped increase the speed with which the signal traveled down the axon to the terminal branches. The impulse triggered a chemical signal, or neurotransmitter, to be released across the synapse to the dendrites of the next neuron. The neurotransmitter bonded to the receptors on the dendrite and the signal changed from chemical back into an electrical impulse. The signal was passed from neuron to neuron in the peripheral nervous system until it entered the central nervous system and traveled up the spinal cord to the motor cortex of the brain. Then, my brain interpreted this stimuli and sent a signal to my arm via depolarization of motor neurons, much like how my arm sent the signal to the brain. Within a few seconds of detecting the stimuli, I was able to shake my arm repeatedly in hopes of getting the stubborn carp to surrender and release itself from my arm. Answer Key- LO 3.43

37. LO:2.2 The student is able to justify a scientific claim that free energy is required for living systems to maintain organization, to grow or reproduce, but that multiple strategies exist in different living system.SP:6.1: the student can justify claims with evidence Explanation: Life requires a constant input of free energy or else the organism will die. Organisms use free energy to maintain organization, such as thermoregulation to regulate body temperature and metabolism. Thermoregulation is the process in which animals maintain an internal temperature within a tolerable range. Endothermic animals such as mammals use thermal energy generated by metabolism to maintain homeostatic body temperatures, while ectothermic animals like fish and reptiles gain heat from external thermal energy such as the sun. Reproduction requires free energy, which causes different reproductive strategies that is a response to the energy availability. For example, if female humans as well as other mammals are not taking in enough food females will not ovulate and are unable to reproduce due to the lack of energy. Free energy is required to grow and survive. Excess acquired free energy (you eat more than you burn) will result in energy storage and growth. Insufficient acquired free energy or not eating enough will result in mass loss. When your body doesn’t have enough free energy your cells will be starved and take energy from apoptosis of crucial cells like your muscles. M.C. Question:Which process does not generate free energy ? A) Oxidative phosphorylation B) An exergonic reaction C) ATP molecules bonds are broken by hydrolysis D) An endergonic reaction Learning Log/Frq-Style Question: All living systems require free energy. Give 2 examples of how changes in free energy availability can result In a disruption of an ecosystem.

38. ANSWER KEY-LO 2.2 Which process does not generate free energy that can be used to do work? A) Oxidative phosphorylation B) An exergonic reaction C) ATP molecules bonds are broken by hydrolysis D) An endergonic reaction All living systems require free energy. Give 2 examples of how changes in free energy availability can result In a disruption of an ecosystem. Changes in producer levels can affect the number and sizes of other trophic levels. If the amount of producers decreases due to drought this will cause a decrease of free energy to all the trophic levels above it. Only about 10% of the energy is passed to the next trophic level due to energy lost as heat. Energy flows through the ecosystem in the form of carbon-carbon bonds and as the bonds are broken the carbon combines with oxygen to form CO2 and energy is released. So if there is a disruption in producers that causes many producers to die there is less energy for the primary consumers and the energy decreases even more as the energy flows up the pyramid. The change in energy resources such as the sun can affect the number and size of the trophic levels. Such factors are light intensity, daily duration, and seasonal changes. Photosynthetic organisms capture free energy from the sunlight. If there is a lack of sunlight it directly affects producers and can cause dramatic effects on plant growth and deprive plants of nutrients which can lead to death. If there are less producers there will less primary, secondary and tertiary consumers within the ecosystem since less food and energy will be available to the higher trophic levels.

39. LO 3.39 The student is able to construct an explanation of how certain drugs affect signal • reception and, consequently, signal transduction pathways. • SP 6.2 The student can construct explanations of phenomena based on evidence produced • through scientific practices. • Explanation: In order to know how the drugs affect signal reception and transduction, we must know the chemicals that can be • replaced by drugs. For example, anti depressants inhibit reuptake and block serotonin from triggering signals in the brain. This inhibits the • entire signal transduction pathway by not allowing the chemical to receive the signal. The evidence for these types of studies are produced • through scientific practices. Many years of research and development have gone into producing drugs that will effectively do what they are • intended to do. In order to be successful on this learning objective, we must be able to take the evidence that is presented to us and interpret • it correctly to make a good explanation of the phenomena of drugs affecting signal reception and signal transduction pathways. • Multiple Choice Practice • Serotonin levels are one of the main components of which type of drugs? • Anti Anxiety • Anti Depressants • Anti Psychotic • Allergy • ADHD • FRQ Example • Explain what occurs when a drug blocks the reception site • of the neurotransmitter. Give a description as well as examples • of what occurs and what does not occur within the neuron • when this occurs.

40. FRQ Answer • Answer Slide • When a drug targets a neurotransmitter receptor on a neuron, it binds to the receptor and inhibits the neurotransmitter from triggering a response from the neuron. A great analogy is that of a lock and key. The lock is the receptor site and the key is the neurotransmitter. When the key turns the lock, the lock opens so when the neurotransmitter binds to the receptor site, the response is triggered. The drug would act as an incorrect key in a lock. It would enter the key hole but it would not be able to turn the lock and unlock the lock. So the drug would fit onto the receptor site but not trigger the neuron to fire. This inhibits the signal transduction pathway. Normally when a neuron is told to fire the response travels down the neuron through the axon to the axon terminal and into the synapse, where the neurotransmitters bind to the dendrites of the next neuron and cause it to fire and give a response. When the receptor site is inhibited, this process does not occur and therefore the signal is not carried on and the response that is desired is not achieved. An example of this is when anti anxiety drugs are taken. The drugs target the receptors for neurons that help facilitate a stress response. This means that the stress response is not achieved as often as it normally would be. This is very helpful to someone with anxiety because it limits the stress that they feel and therefore lowers the anxiety that they feel. These signal blocking drugs do wonders for people and help a lot in dealing with mental health issues. • Multiple Choice Practice • Serotonin levels are one of the main components of which type of drugs? • Anti Anxiety • Anti Depressants • Anti Psychotic • Allergy • ADHD

41. Learning Objective 3.50: The student is able to create a visual representation to describe how the vertebrate brain integrates information to produce a response.Science Practice 1.1: The student can create representations and models of natural or man-made phenomena and systems in the domain. Multiple Choice Question: In the diagram above, what process is occurring at stage 3? The retina is sending a hormone to the brain. The axon terminals of the optical nerve are releasing neurotransmitters. An electrical signal is passing through the synapses between the optical nerve and the brain. Light is passing through the pupil and into the neurons. Explanation: At the cellular level, individual neurons receive information from their dendrites and produce a response in a neighboring cell(s) through their axons. The stimulus-integration-response process in the brain as a whole relies upon the chemical signals called neurotransmitters which effect the polarity of neurons. The stimulus, say light received by the eye, is translated to an electric neural impulse (action potential) and sent to the dendrites of the associated sensory neuron(s). These sensory neurons, if stimulated to threshold, will pass the action potential along their axon and send neurotransmitters from the axon terminals to alert the next neuron, and so forth in a chain of signal transmission. Eventually, the signal will reach its final location in the brain. Neurons which receive the signal may be hyperpolarized (inhibited from firing) or depolarized (stimulated to fire). If these final neurons fire, instead of sending a signal to another neuron they prompt a response in other body cells. The number of neurons firing and not firing determines the strength of the response In the eye example mentioned earlier, when retinal cells receive a dim-light stimulus, the ultimate response is for neurons to stimulate the release of melatonin by the pineal gland. If retinal cells send a bright-light signal, the response neurons will be prevented from stimulating the pineal gland. Free Response Question: A person with a phobia of bugs feels a tickling sensation on her arm and immediately reacts by swatting at the offending insect. Explain a) how her brain received the signal from her skin and b) how her brain prompted the “swatting” motor response.

42. Answer Key Multiple Choice Question: In the diagram above, what process is occurring at stage 3? • The retina is sending a hormone to the brain. • The axon terminals of the optical nerve are releasing neurotransmitters. • An electrical signal is passing through the synapses between the optical nerve and the brain. • Light is passing through the pupil and into the neurons. Free Response Question: A person with a phobia of bugs feels a tickling sensation on her arm and immediately reacts by swatting at the offending insect. Explain a) how her brain received the signal from her skin and b) how her brain prompted the “swatting” motor response. a) The sensory neurons beneath her skin note the light pressure of the bug’s legs on her skin, through their dendrites. These neurons, part of the peripheral nervous system (PNS), are stimulated to -55 mv, their threshold, and they send an action potential (electrical signal) down their axons. At the axon terminal, the action potential is converted to a chemical signal, causing vesicles to release neurotransmitters. The neurotransmitters cross the synapse to trigger the next PNS neuron to fire. This continues until the signal reaches a spinal nerve, entering the central nervous system (CNS), which passes the signal on to the brain (also CNS). b) The brain, having received the sensory signal, processes the impulse. The bug-phobiac consciously decides to swat the bug, so her brain initiates action potentials in neurons in the motor cortex. In a cascade of neurotransmitters-dendrites-action potential-axon repetitions, the swatting signal travels from the brain to the spinal cord, then out of the spinal cord and to the PNS motor neurons that lead to her arm and hand. Finally, the last motor neurons in the chain are paired with muscle cells, not other neurons. When they fire an action potential down their axons, they instruct those muscle cells to contract, and the swatting motion is carried through.

43. 1) Learning Objective 4.19: The student is able to use data analysis to refine observations and measurements regarding the effect of the population interactions on patterns of species distribution and abundance. 2) Science Practice 5.2: The student can refine observations and measurements based on data analysis. 3) The student is able to look at and interpret data presented in graphs and tables from studies done on species distribution and patterns of populations and be able to analyze and understand the data and give a conclusion that shows they understood the data presented. Graphs can include the population pyramid graphs (that can illustrate growth patterns in populations), “S” and “J” curves with carrying capacities, and birth/death rate line graphs. In order to understand the graph the student must understand that the total growth of a population is the birth rate minus the death rate. Multiple Choice Question Which of the following can be concluded from the data presented in the graph (“Age Distribution, 2000”)? A) The country is still developing B) The population experienced a high birth rate around the years 1955-1975 C) The birth rate has increased since 1975 D) Males tend to live longer than females. Free Response Question Identify three things that would keep a population from continuing to grow.

44. KEY Multiple Choice Question Which of the following can be concluded from the data presented in the graph (“Age Distribution, 2000”)? A) The country is still developing B) The population experienced a high birth rate around the years 1955-1975 C) The birth rate has increased since 1975 D) Males tend to live longer than females Free Response Answer One thing that would keep a population from continuing to grow is that carrying capacity of the are or how many individuals the area can provide resources for. Another is the population size of predators of the population. The predators will even out the birth rate and death rate to keep the population at a healthy level. The death rate is extremely important also when controlling growth of the population. Things like diseases, predators, and lack of resources help keep the death rate at a healthy level to keep the population in check.

45. LO 2.40: The student is able to connect concepts in and across domain(s) to predict how environmental factors affect responses to information and change behavior. SP 7.2: The student can connect concepts in and across domains to generalize or extrapolate in and/or across enduring understandings of big ideas. Explanation: In humans, temperature regulation is important for cellular processes and organ function. Humans are endotherms, organisms that create their own heat, and we keep our internal body temperature of 98°F and 100°F. If the internal temperature reaches a certain point above normal body temperature, enzymes could denature and create serious problems at the cellular level. When our environment changes in temperature the sensors in our blood vessels inform the hypothalamus, located in the brain, of this change. The hypothalamus will alert the body and different responses will then begin in order to maintain the body temperature balanced. An example would be if the body temperature drops below 37°C, vasoconstriction to decrease the flow of heat from blood to skin and shivering to increase heat production. Some animals can erect their fur to create insulation and protect their skin from harsh wintery winds. M.C.: Which of the following statements about temperature regulation in humans is false? A) Body temperature is not regulated by the cerebellum. B) Normal body temperature in humans is 98°F and 100°F C) One way the body can reduce body temperature is by constricting blood vessels D) There are several neurotransmitters that take part in the regulation of temperature. Learning Log/FRQ-Style Question: How does the body maintain normal body temperature? How would that be affected if the hypothalamus was removed from the process?

46. Answer Key—LO 4.1 M.C.: Which of the following statements about temperature regulation in humans is false? A) Body temperature is not regulated by the cerebellum. B) Normal body temperature in humans is 98°F and 100°F C) One way the body can reduce body temperature is by constricting blood vessels D) There are several neurotransmitters that take part in the regulation of temperature How do endotherms maintain normal body temperature? How would that be affected if the hypothalamus was removed from the process? The body maintains a constant body temperature by the continuous communication between the hypothalamus and sensors in the blood vessels. If the body gets too hot, the sensors will send a signal alerting the hypothalamus to dilate the vessels and the sweat glands to activate. The removal of the hypothalamus will result in the body not having the ability to regulate the internal body temperature in endotherms. Organs would begin to fail because of essential proteins denaturing and levels of ATP dramatically being reduced.

47. LO 3.17 The student is able to describe representations of an appropriate example of inheritance patterns that cannot be explained by Mendel’s model of the inheritance of traits. SP 1.2 The student can describe representations and models of natural or man-made phenomena and systems in the domain. Explanation: You should be able to talk about abnormal patterns of inheritance. This is NOT your typical Mendel model where inheritance is based on two genes and complete dominance. This is incomplete dominance and codominance. In incomplete dominance, the genes mix and are incompletely shown by heterozygotes. In codominance, both genes are shown by heterozygotes. For example, incomplete dominance is when you mix red flower genes and white flower genes to get a pink flower. Codominance is when you mix black and white to get spots/stripes/speckles. This also includes inheritance through multiple alleles. Blood type is inherited this way. There is IA, IB, and i. They combine to form four different blood types: Type A, Type B, Type AB, and Type O. Type A can be IA, IA or IA, i. Type B can be IB, IB or IB, i. Type AB is IA, IB. Type O is i, i. Multiple Choice Practice: Linda and Ron want to grow all pink flowers for their garden. They have homozygous white flowers (WW), homozygous red flowers (RR), and pink flowers (RW). Assuming that the mode of inheritance for this gene is incompletely dominant, which of the following crosses would be most likely to produce the most pink flowers? A)RW X RW B)WW X WW C)WW X RR D)WW X RW E)None of these crosses would produce pink flowers. FRQ: Jeremy is a biologist studying cats. He crosses a white cat with a black cat. This results in a litter of 12 grey cats. What mode of inheritance does the fur color gene follow? What would happen if two grey offspring were crossed? Use a properly labeled diagram to support your answer. Incomplete Dominance Codominance

48. Answer Key LO 3.17 Multiple Choice Practice: Linda and Ron want to grow all pink flowers for their garden. They have homozygous white flowers (WW), homozygous red flowers (RR), and pink flowers (RW). Assuming that the mode of inheritance for this gene is incompletely dominant, which of the following crosses would be most likely to produce the most pink flowers? A)RW X RW B)WW X WW C)WW X RR D)WW X RW E)None of these crosses would produce pink flowers. FRQ: Jeremy is a biologist studying cats. He crosses a white cat with a black cat. This results in a litter of 12 grey cats. What mode of inheritance does the fur color gene follow? What would happen if two grey offspring were crossed? Use a properly labeled diagram to support your answer. The inheritance pattern is incomplete dominance. If two grey offspring were crossed Jeremy would expect to have ¼ black offspring, ¼ white offspring, and ½ grey offspring. This is demonstrated by the diagram to the right. B is the black fur gene; W is the white fur gene. BB= black fur. WW= white fur. BW= grey fur.

49. LO 3.37 The student is able to justify claims based on scientific evidence that changes in signal transduction pathways can alter cellular response. SP 6.1 The student can justify claims with evidence. Explanation: As we all know a signal transduction pathway is the process by which a signal on a cells surface is converted into a specific cellular response. Cells use these pathways to transmit practically any cellular signal. Normally a ligand would bind to a receptor, the receptor would then trigger transduction in which relay molecules move down the transduction pathway triggering the production of secondary messengers, which go on to create the cellular response. These pathways may be interrupted by poisons or diseases in the body. Sometimes changes may occur that affect the signal from creating its desired response. A disease or poison can interfere with the pathway in many different ways. Some poisons target the cellular receptor protein and basically tell the receptor to ignore the ligand that binds to it to initiate the signal transduction pathway. A good example of this is type two diabetes. Scientists have found that type two diabetes is caused by a inhibition of the protein tyrosine kinase receptor causing it to ignore its ligand, insulin. Since this pathway never begins the glucose transporters cannot open to allow glucose to enter the cell so that it can be used or stored. Other disruptions include the blocking of enzymes and/or the production of a secondary messenger. Many of these disruptions can be deadly. Insulin signal transduction pathway and response Multiple Choice: What can you expect to occur if a persons membrane bound insulin receptor proteins are being inhibited? Insulin will diffuse through the cell membrane and bind to an intercellular receptor that is not being inhibited. An alternate pathway will be created to activate glucose transporters. There will be an increase in blood glucose levels. Cells will begin to go use energy reserves until the insulin receptor proteins are uninhibited. FRQ: A new disease is causing the production of destructive enzymes that are destroying perfectly healthy cells from the inside out. How would you plan to fight this disease? Draw a generalized diagram of how this disease is producing these enzymes and how your treatment could prevent the disease.

50. Multiple Choice: What can you expect to occur if a persons membrane bound insulin receptor proteins are being inhibited? Insulin will diffuse through the cell membrane and bind to an intercellular receptor that is not being inhibited. An alternate pathway will be created to activate glucose transporters. There will be an increase in blood glucose levels. Cells will begin to go use energy reserves until the insulin receptor proteins are uninhibited. Answer Key A new disease is causing the production of destructive enzymes that are destroying perfectly healthy cells from the inside out. How would you plan to fight this disease? Draw a generalized diagram of how this disease is producing these enzymes and how your treatment could prevent the disease. If the disease is causing the production of digestive enzymes then it must be using a signal transduction pathway to send a signal to the nucleus of the cell. In the nucleus the signal probably activates transcription factors to transcribe an mRNA strand that is then to be translated into protein and finally the enzyme. In order to stop the production of this enzyme you could target which type of protein receptor the disease is using to start its signal and develop a ligand that could inhibit those particular receptors. This would cause this harmful signal transduction pathway to be blocked so the cell would never respond by making the deadly enzyme. Diagram Inhibitory ligand ribosome Polypeptide chain to form digestive enzyme