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Chapter 1 - Introduction: Exploring Life

Figure 1.1. Chapter 1 - Introduction: Exploring Life. NEW AIM: What are the major characteristics of life?. Chapter 1 - Introduction: Exploring Life. AIM: What are the major characteristics of life?. Chapter 1 - Introduction: The Scientific Study of Life.

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Chapter 1 - Introduction: Exploring Life

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  1. Figure 1.1 Chapter 1 - Introduction: Exploring Life NEW AIM: What are the major characteristics of life?

  2. Chapter 1 - Introduction: Exploring Life AIM: What are the major characteristics of life?

  3. Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life Chapter 1 - Introduction: Exploring Life AIM: How is life organized? AIM: What are the major characteristics of life? Biology? The study of life (organisms and how they interact with the biotic and abiotic components of their environments or surroundings) How does one define life or living?

  4. Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life AIM: How is all life united? AIM: What are the major characteristics of life? Characteristics of Life (Living vs. Non-Living)

  5. Chapter 1 - Introduction: Exploring Life 1. Organization/order All life is ordered/organized, which is why energy is always needed (must maintain this order). The atoms that make us up can be arranged in a countless number of ways, but only a handful of those will result in you…a working organism. Any arrangement outside of this handful results in death. Recall the 2nd law of thermodynamics… With every transfer of energy, the universe becomes more disordered. There are MANY energy transfers within and around you resulting in disorder, and therefore you must constantly be maintaining order. Fig. 1.3

  6. Chapter 1 - Introduction: Exploring Life 1. Organization Hierarchy of Life Going from the basic level of subatomic particles (protons, electrons, neutrons, etc…) to the more complex level of ecosystems Emergent Properties Notice as we move up the hierarchy, new properties come to be that were not there before. For example, atoms alone like carbon, nitrogen, oxygen, hydrogen and phosphorus cannot store information to build organisms, but combine them to form a molecule called DNA and you now have a new property…information storage. Fig. 1.3

  7. Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life AIM: How is all life united? AIM: What are the major characteristics of life? 1. Organization The hierarchy of life: 1. Atoms (carbon, nitrogen, oxygen, hydrogen, etc…) combine to form molecules (proteins, carbohydrates, lipids, nucleic acids, vitamins). 2. Molecules combine to form organelles (nucleus, ribosomes, plasma membrane, ER, golgi, etc…)

  8. Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life AIM: How is all life united? AIM: How is all life united? AIM: What are the major characteristics of life? 1. Organization The hierarchy of life: 3. Organelles combine to form cells What is a cell? The most basic unit of life (the lowest level on the hierarchy that can perform all the functions of life) Let’s take a closer look at cells…

  9. Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life Chapter 4 - A Tour of the Cell AIM: What are the major characteristics of life? AIM: How is all life united? AIM: How can we observe cells? Cell New cells come from pre-existing cells with the exception of the first cell, and that the cell is the most basic unit of all living organisms. Theory Credit for this theory is given to: Theodor Schwann Matthias Jakob Schleiden Rudolf Virchow (German Physiologist) (German Doctor, Biologist,…) (German Botanist) All cells from pre-existing cells Cell is basic unit of life

  10. Chapter 3 - The Molecules of Cells Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life AIM: How is all life united? AIM: What are the major characteristics of life? AIM: How can we observe cells? Scaled Size of a cell Imagine Madison Square Garden (MSG), to be a cell…how big is a protein in this cell? Reminder, a protein in the cell would be like a tennis ball in MSG and the DNA would be like a rope with a thickness of 2mm and a length of 1200 miles.

  11. Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life Chapter 4 - A Tour of the Cell AIM: How is all life united? AIM: What are the major characteristics of life? Two major forms of cells evolved on Earth 1. Prokaryotes (bacteria or the kingdom monera) - Two types A. Eubacteria DNA in blue, ribosomes are the black dots B. Archaebacteria - No internal membranous organelles No nucleus, ER, golgi, lysosomes, peroxisomes, etc… - First to evolve, simpler Pro-, coming before. Karyo = nucleus

  12. Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life Chapter 4 - A Tour of the Cell AIM: How is all life united? AIM: What are the major characteristics of life? Two major forms of cells evolved on Earth 2. Eukaryotes (animals, plants, protists, fungi) - A fusion of prokaryotes Endosymbiotic theory Mitochondria and Chloroplasts were once free-living prokaryotes that at some point in evolution cooperated with another larger prokaryote to eventually become one…the eukaryotic cells.

  13. Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life Chapter 4 - A Tour of the Cell AIM: How is all life united? AIM: What are the major characteristics of life? Two major forms of cells evolved on Earth 1. Eukaryotes (animals, plants, protists, fungi) - A fusion of prokaryotes - Membranous organelles Nucleus, ER, golgi, lysosomes, peroxisomes, etc… DNA found inside the purple nucleus - More complex Eu-, true. Karyo = nucleus

  14. EUKARYOTIC CELL PROKARYOTIC CELL DNA (no nucleus) Membrane Membrane Cytoplasm Organelles 1 µm Figure 1.8 Nucleus (contains DNA) Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life Chapter 4 - A Tour of the Cell AIM: How is all life united? AIM: What are the major characteristics of life? Two major forms of cells evolved on Earth

  15. Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life Chapter 4 - A Tour of the Cell AIM: How is all life united? AIM: What are the major characteristics of life? NEW AIM: How are eukaryotic cells organized? Does more complex mean better? More complex means more that can break, more to maintain against the 2nd law of thermodynamics, more to form(longer development time), etc… Both types of cell exist on Earth and therefore they both work. If it works it works…neither is “better”. If eukaryotes go extinct, then you might say the prokaryotes were better, but only better in the environment that caused the eukaryotes to go extinct…

  16. Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life Chapter 4 - A Tour of the Cell AIM: How is all life united? AIM: What are the major characteristics of life? NEW AIM: How are eukaryotic cells organized? Does more complex mean better?

  17. Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life Chapter 4 - A Tour of the Cell AIM: How is all life united? AIM: What are the major characteristics of life? Size Comparison Analogy The Basketball, The Battery and the Pin Head Eukaryotic cell (1/100th to 1/10th mm) Virus (just the pin head) 1/20,000th mm Prokaryotic cell 1/1000th to 1/100th mm

  18. Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life AIM: How is all life united? AIM: How is all life united? AIM: What are the major characteristics of life? 1. Organization The hierarchy of life: Figure 1.5 Figure 1.5 – a eukaryotic cell undergoing mitosis. Chromosomes (DNAplus associated proteins) are stained blue, microtubules are green and the cytoskeleton is red. The left panel is anaphase and the right is telophase. Let’s briefly focus on the chromosomes / DNA…structure and function?

  19. Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life AIM: How is all life united? AIM: How is all life united? AIM: What are the major characteristics of life? 1. Organization The hierarchy of life: Structure of DNA: Figure 1.7 DNA nucleotide monomers (A,C,T,G) combine to form the double-stranded DNA polymer. Base pairs between strands: DNA (deoxyribonucleic acid) – two stranded polymer of nucleotides A, T, C and G forming a double helix. A pairs with T C pairs with G

  20. Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life AIM: How is all life united? AIM: How is all life united? AIM: What are the major characteristics of life? 1. Organization The hierarchy of life: Figure 1.7 Structure of DNA: DNA nucleotide monomers (A,C,T,G) combine to form the double-stranded DNA polymer. Structure determines function… The structure of a hammer determines its function to hit nails. Likewise, the structure of a pencil allows for its function to write. How does the structure of DNA relate to its function?

  21. Chapter 3 - The Molecules of Cells Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life AIM: How is all life united? AIM: What are the major characteristics of life? AIM: How do organisms build/break macromolecules? 1. Organization The hierarchy of life: Function of DNA / chromosomes: DNA (a chromosome) is a book written in only 4 letters!! The DNA, like all books, stores information. What is this information? Instructions to build every RNA and polypeptide (protein) in the cell. DNA is found in the nucleus of eukaryotic cells or the nucleoid region of prokaryotic cells. Each piece called a chromosome. They are books making the nucleus of eukaryotic cells the library. All of the chromosomes in a cell is called the genome.

  22. Sperm cell Nuclei containing DNA Embyro’s cells with copies of inherited DNA Fertilized egg with DNA from both parents Figure 1.6 Offspring with traits inherited from both parents Egg cell Chapter 1 - Introduction: Exploring Life Chapter 1 - Introduction: The Scientific Study of Life Chapter 3 - The Molecules of Cells AIM: How is all life united? AIM: What are the major characteristics of life? AIM: How do organisms build/break macromolecules? 1. Organization The hierarchy of life: Function of DNA / chromosomes: DNA is the hereditary molecule of life Proteins [and in certain cases RNA] built you, but the information to build them is stored in the DNA. The books are passed on to the next generation (heritable)…

  23. Chapter 3 - The Molecules of Cells Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life AIM: How is all life united? AIM: What are the major characteristics of life? AIM: How do organisms build/break macromolecules? 1. Organization The hierarchy of life: Function of DNA / chromosomes: Genetic Variation We all obviously have slightly different books (chromosomes) that code for slightly different proteins/RNA that will in turn build us slightly differently. Why is genetic variation important? Because the environment is changing around us. If we were all identical, a change that caused one of us to die would cause all of us to die….

  24. Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life AIM: How is all life united? AIM: How is all life united? AIM: What are the major characteristics of life? 1. Organization The hierarchy of life: 3. Organelles combine to form cells (muscle cells, neurons, blood cells, etc…) 4. In multicellular organisms, cells combine to form tissues: muscle tissue, nervous tissue, connective tissue, and epithelial tissue (there are only 4 types). 5. Tissues combine to form organs like the heart, lungs, pancreas, liver etc…

  25. Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life AIM: How is all life united? AIM: How is all life united? AIM: What are the major characteristics of life? 1. Organization The regents focuses mainly on the immune, reproductive and endocrine systems The hierarchy of life: 6. Organs combine to form the organ systems:

  26. Chapter 20: Unifying Concepts of Animal Structure and Function Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life AIM: How is all life united? AIM: What are the major characteristics of life? AIM: How are animals organized? Organs cooperate to build organ systems: Function is to obtain nutrients – proteins, carbohydrates, lipids, nucleic acids, vitamins, minerals. Nutrients are first ingested, then digested (large molecules broken down into smaller ones – protein to amino acids, polysaccharides to monosaccharides, nucleic acids to nucleotides, etc… so they can be absorbed by the small intestines into the blood for transport). All undigestable material (roughage/fiber/cellulose) will be egested. Fig. 20.9

  27. Chapter 20: Unifying Concepts of Animal Structure and Function Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life AIM: How is all life united? AIM: What are the major characteristics of life? AIM: How are animals organized? Organs cooperate to build organ systems: Serves for gas exchange. Bring in molecular oxygen (O2) to your blood, which will be used to perform cell respiration by your cells. Get rid of CO2 and H2O waste (excrete) in the blood coming from cell respiration. Fig. 20.9

  28. Chapter 20: Unifying Concepts of Animal Structure and Function Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life AIM: How is all life united? AIM: What are the major characteristics of life? AIM: How are animals organized? Organs cooperate to build organ systems: The heart pumps blood around your body in hollow tubes made of cell called arteries (take blood away from heart), veins (bring blood toward heart), and capillaries (where nutrients and waste diffuse to cells). These would be the roadways of your body. The blood also carries other substance like white blood cells (WBC’s – immune system) and red blood cells (carry oxygen). Fig. 20.9

  29. Chapter 20: Unifying Concepts of Animal Structure and Function Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life AIM: How is all life united? AIM: What are the major characteristics of life? AIM: How are animals organized? Organs cooperate to build organ systems: Cleans the blood of metabolic waste (waste from chemical reactions) like H2O from cell respiration, and urea (form of nitrogenous waste) from deamination. The kidney are “blood filters”, removing urea, excess salt or excess water and other undesirable chemicals from the blood. Although not shown, the respiratory system has excretory function in the elimination of CO2 since it is a gas along with the skin, which will release some urea, salt and water as sweat. Fig. 20.9

  30. Chapter 20: Unifying Concepts of Animal Structure and Function Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life AIM: How is all life united? AIM: What are the major characteristics of life? AIM: How are animals organized? Organs cooperate to build organ systems: CELLS TALK TO EACH OTHER (cell signaling)… Your cells must be able to talk to each other in order to cooperate to maintain homeostasis, and to be able to survive and reproduce… ***Homeostasis is NOT EQUILIBRIUM!! In order to be alive, we cannot be at equilibrium. Homeostasis maintains a specific internal environment (order), which is far from equilibrium. Think about your body temperature…is this at equilibrium? We are endotherms (warm-blooded) and maintain a body temp not at equilibrium with our surroundings typically. Fig. 20.9

  31. Chapter 20: Unifying Concepts of Animal Structure and Function Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life AIM: How is all life united? AIM: What are the major characteristics of life? AIM: How are animals organized? Organs cooperate to build organ systems: Your cells must be able to talk to each other. For example, insulin from the pancreas instructs the liver to take up glucose from the blood. The endocrine system uses hormones (special chemicals – usually amino acid based - ex. Insulin, or steroid (lipid) based – ex. testosterone) put into the bloodby endocrine cells. The hormone will bind to receptor proteins on target cells and signal them to perform certain functions. This system is typically slow and long term – takes a while for the hormones to circulate and they will stay around a while… CELLS TALK TO EACH OTHER (cell signaling)… Fig. 20.9

  32. Chapter 20: Unifying Concepts of Animal Structure and Function Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life AIM: How is all life united? AIM: What are the major characteristics of life? AIM: How are animals organized? Organs cooperate to build organ systems: The nervous system is also all about cellular communication, but instead of using chemicals released into the blood, it uses cells that act like wires called neurons that transmit electrical signals. These signals are extremely fast (up to 120 m/s) and are typically short lived. An example would be moving your finger or any other skeletal muscle. The electrical signal is sent from your brain, down your spinal cord and out to the muscle in your finger. CELLS TALK TO EACH OTHER (cell signaling)… Fig. 20.9

  33. Chapter 20: Unifying Concepts of Animal Structure and Function Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life AIM: How is all life united? AIM: What are the major characteristics of life? AIM: How are animals organized? Organs cooperate to build organ systems: There are millions upon millions of bacteria, fungi, parasitic worms, etc… that would love nothing more than to take your organic molecules and make them lunch. Luckily you have an immune system. This systems protects your body from foreign substance. White blood cells are responsible for the destruction of these substances. They, like all blood cells, are born in the bone marrow and secrete antibodies (a type of protein) that will stick to foreign molecules called antigens on bacteria, viruses, etc... Anything antibodies stick to will be eaten by other white blood cells. Fig. 20.9

  34. Chapter 20: Unifying Concepts of Animal Structure and Function Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life AIM: How is all life united? AIM: What are the major characteristics of life? AIM: How are animals organized? Organs cooperate to build organ systems: What is life without a reproductive system? Nonexistent. This one if fairly self-explanatory. It is also the only system not required for the organism itself to survive. Gametes (sex cells = sperm and egg/ovum) are made in the gonads (testes and ovaries). Fig. 20.9

  35. Chapter 20: Unifying Concepts of Animal Structure and Function Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life AIM: How is all life united? AIM: What are the major characteristics of life? AIM: How are animals organized? Organs cooperate to build organ systems: The muscular system is composed of all the skeletal muscles of the body. The skeletal muscles allow the body to move when combined with signals from the nervous system (and a lot of ATP of course). Ligaments attach bone to bone. Tendons attach muscle to bone. Muscle cells can ONLY contract (get shorter) – you cannot signal a muscle to extend. Life is simply a series of movements (energy transfers). Fig. 20.9

  36. Chapter 20: Unifying Concepts of Animal Structure and Function Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life AIM: How is all life united? AIM: What are the major characteristics of life? AIM: How are animals organized? Organs cooperate to build organ systems: The skeletal system serves to support the body (without it you would be a blob on the floor), protects vital organs like your lungs, brain, spinal cord and heart, and contains marrow that produces blood cells. The integumentary system is composed of the skin, hair and nails (feathers and scales), all of which are mostly non-living. This system serves to waterproof, cushion and protect the deeper tissues, excrete wastes, regulate temperature, is the attachment site for sensory receptors to detect pain, sensation, pressure and temperature, and may attract a mate. Integere means “to cover” (latin) Fig. 20.9

  37. Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life Chapter 5 - Energy and the Cell AIM: How is all life united? AIM: What are the major characteristics of life? AIM: Describe the process of active transport. Comparing single to multicellular organisms

  38. Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life Chapter 5 - Energy and the Cell AIM: How is all life united? AIM: What are the major characteristics of life? AIM: Describe the process of active transport. Comparing single to multicellular organisms

  39. Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life AIM: How is all life united? AIM: How is all life united? AIM: What are the major characteristics of life? 1. Organization Organ systems cooperate: Ex. Nutrients from digestive system are transported to cells by circulatory system Ex. Hormones from the endocrine system regulate the reproductive system

  40. Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life AIM: How is all life united? AIM: How is all life united? AIM: What are the major characteristics of life? 1. Organization Organ systems cooperate: Ex. When body temp drops, nerve impulses from brain signal muscles to contract and shiver Ex. Waste products from chemical reactions are transported by the circulatory system to the kidney/lungs/skin for removal (excretion).

  41. Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life AIM: How is all life united? AIM: How is all life united? AIM: What are the major characteristics of life? 1. Organization The hierarchy of life: 7. Organ systems combine to form organisms 8. Organisms that can reproduce with each other collectively form a population (species) 9. Different populations combine to form communities (squirrels, birds, humans all living in an area). 10. Communities (biotic-living) combine with the rest of the abiotic (non-living) substances like soil, water, air to form the ecosystem. Let’s take a closer look at ecosystems…

  42. Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life NEWAIM: How are organisms connected to the environment? AIM: How is all life united? AIM: What are the major characteristics of life? Producers = autotrophs = organisms that make their own food (food = organic molecules) by photosynthesis or chemosynthesis Consumer = heterotroph = steal/obtain food (organic molecules) from the producers or other consumers

  43. Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life AIM: How are organisms connected to the environment? AIM: How is all life united? AIM: What are the major characteristics of life? What does this diagram show/tell us? Chemicals cycle within ecosystems Earth is essentially not accumlating or losing mass. Therefore, matter must be recycled and used over and over by organisms. The molecules your are made of were part of countless other organisms in the past and will be part of countless others in the future. Energy flows through ecosystems Energy enters for the most part as light from the sun with the exception of rare deep sea thermal vent and cave ecosystems. The energy of the light is captured during photosynthesis and stored in the electrons of organic molecules. As energy is transferred between molecules, a small amount is lost with each transfer. Eventually all the energy is lost as infrared light to outer space. Therefore energy must always be coming into ecosystem. Fig. 1.4

  44. Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life AIM: How are organisms connected to the environment? AIM: How is all life united? AIM: What are the major characteristics of life? Explain how the atoms that make up me could be part of you at some point in the future. Explain why the energy stored within me will likely never be used by your cells to build/maintain/repair you. Fig. 1.4

  45. Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life AIM: How is all life united? AIM: How is all life united? AIM: What are the major characteristics of life? 1. Organization Reductionism vs Holism View Points Reductionism Complex systems like an ecosystem can be explained by its simpler / fundamental components like DNA in combination with the basic laws of chemistry, physics, etc… Holism A complex system cannot be explained by its simpler parts alone. It must be looked at as a whole [“The whole is greater than the sum of its parts” – Aristotle, emergent properties]

  46. Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life AIM: How is all life united? AIM: How is all life united? AIM: What are the major characteristics of life? 2. Regulation (homeostasis) Homeostasis is maintaining a stable internal environment conducive to life. Examples: 1. Body Temperature - Get too hot, sweat; get too cold, shiver 2. Blood glucose levels - Glucose too high, insulin secreted from pancreas telling liver and muscle cells to take up glucose from blood and store as glycogen. - Glucose too low, glucagon secreted from pancreas telling liver to break down glycogen and release glucose into blood. 3. Number of red blood cells

  47. Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life AIM: How is all life united? AIM: How is all life united? AIM: What are the major characteristics of life? 2. Regulation (homeostasis) Remember that homeostasis does not maintain equilibrium, but in fact prevents equilibrium as the conditions required to maintain life are not those of equilibrium.

  48. Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life AIM: How is all life united? AIM: How is all life united? AIM: What are the major characteristics of life? 2. Regulation (homeostasis) Example? Glucose levels in the blood – eat a candy bar and blood glucose levels rise above the homeostatic level of 90mg/dl. Consistent high glucose levels denature proteins and in turn damage cells, the result of diabetes. The pancreas (endocrine gland) senses the rise in glucose and secretes the hormoneinsulin. Hormones are chemicals secreted directly into the blood and talk to other cells (bind protein receptors). Insulin receptors are located on the surface of muscle cells (myocytes – myo = muscle, cyte = cell), fat cells (adipocytes) and liver cells (hepatocytes). These cells are triggered to take up glucose and store it as glycogen (polymer of glucose) in the smooth ER (adipocytes will convert it to fat and store it in this form).

  49. Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life AIM: How is all life united? AIM: How is all life united? AIM: What are the major characteristics of life? 2. Regulation (homeostasis) Negative Feedback is one way and often used to maintain homeostasis A basic means of maintaining a certain concentration or level in a system like the body where the product or output shuts its own production off. Classic example – Thermostat: 1. Room is cold 2. Thermostat sends signal to furnace to generate heat 3. Heat (output) added to the room 4. Heat shuts thermostat off (negative feedback) at a set temperature like 72 degree F thereby shutting its own production off, regulating the temperature of the room

  50. A A Negative feedback Enzyme 1 Enzyme 1 B B Enzyme 2 C C Enzyme 3 D D D D D D D D D D D Figure 1.11 Chapter 1 - Introduction: The Scientific Study of Life Chapter 1 - Introduction: Exploring Life Chapter 1 - Introduction: The Scientific Study of Life AIM: How is all life united? AIM: How is all life united? AIM: What are the major characteristics of life? 2. Regulation (homeostasis) Negative Feedback General Biological Example: Three enzymes [proteins that catalyze reactions] (enzyme 1, 2 and 3) convert molecules A into molecule D (the output). Molecule D then binds to enzyme 1, shutting it off, which in turn shuts its own production off. This maintains/regulates a specific level of molecule D.

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