Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.
Chapters 5.1 to 5.7 Ms. Doshi
ANNOUNCEMENT!WE HAVE SPECIAL CLASS NEXT WEEK ON TUESDAY 11/4 at 4 pm, Room 16320. LOOK AT CLASS PLAN ON WEBSITE!
Class Rules • Work together • Help each other • Do the worksheets or questions. • Have your notebook. • Have your textbook. • Use your smartphone for STUDYING only. • If you are not working in class, you will get MINUS POINTS.
Review • Read Chapters 5.1 and 5.2 • Do the review worksheet from the website. • Write your answers on a separate piece of paper or in your notebook. • You have 20 minutes
Chapter 5.3 AND EXTRA PROBLEMS
Genome • The full set of DNA in an individual organism is called a genome. • One or more unique pieces of DNA is called a chromosome. • circular in prokaryotes • linear in eukaryotes • A specific sequence about 30, 000 bases long is a gene.
Heredity • Heredity – the passing of traits from parents to offspring . • It has been estimated that more than 8 million combinations are possible from the 23 chromosomes inherited from each parent. The more than 8 million combinations from each parent will produce more than (8 × 106)(8 × 106) or 6.4 × 1013 (64 trillion) possible combinations for offspring. Your genetic makeup is one of those combinations.
Alleles • alleles: two or more alternate forms of a gene. The alleles are located at the same position on one of the pairs of homologous chromosomes. • dominant: the allele that, if present, is ALWAYS expressed. Example: TT or Tt • recessive: the allele that is expressed only if it is not in the presence of the dominant allele i.e. if the individual is homozygous for the recessive allele. Example: tt
Homozygous vs Heterozygous • homozygous: describes an individual that carries two of the same alleles for a given characteristic • Example: The homozygous condition for a tall-stem plant would be TT. The homozygous condition for a short-stem plant would bett. • heterozygous:describes an individual that carries two different alleles for a given characteristic • Example: The only heterozygous condition possible for stem length in a garden pea is Tt.
The Punnett Square • Punnett square: a diagram that summarizes every possible combination of each allele from each parent; a tool for determining the probability of a single offspring having a particular genotype
Monohybrid Cross • Monohybrid Cross:a cross designed to study the inheritance of only one trait Examples of one trait: color of eyes, color of hair, height of plants. • genotype: the code carried by the organism • phenotype: thephysical characteristics of the organism seen, as a result of the code.
Let’s do together... • In humans brown eyes are dominant over blue eyes. What type of offspring would you expect if you crossed a heterozygous brown eyed person to a heterozygous brown eyed person?
Let’s do together... • In humans tongue rolling is dominant to non-tongue rolling. What would be the expected type of offspring if a homozygous tongue roller was crossed to a heterozygous tongue roller?
Let’s do together... In a certain plant yellow fruit is dominant to white fruit. A heterozygous plant with yellow fruit is crossed with a plant with white fruit. Determine the probable offspring.
Let’s do together... Tall plants are dominant to short plants in the garden pea plant. Cross a heterozygous tall plant to a heterozygous tall plant.
Monohybrid Cross Now..It’s your turn. Do Worksheet 1 from the website.
Genome Sizes of Various Organisms In humans, genes make up only 2% of DNA. These genes all code for proteins. The rest is “non coding DNA” which may or may not have a purpose. We don’t know what it does yet. So, not all DNA codes for proteins. ONLY genes code for proteins.
DNA in Eukaryotes • regions of DNA are in color in the picture. • regions of DNA that do not code for proteins are in gray. • 75% of non-coding regions of DNA are between genes . • 25% of non coding regions inside genes are called introns.
How Genes Work: In Eukaryotes DNA (gene) In the nucleus Transcription mRNA mRNA leaves nucleus through nuclear pores In the cytoplasm Translation Proteins
How Genes Work: In Prokaryotes DNA (gene) In the cytoplasm Transcription mRNA In the cytoplasm Translation Proteins
Questions 1 • _______% of fruit fly DNA codes for genes. • _______% of human DNA codes for genes. • Non coding DNA inside genes are called ________. • What is transcription? • What is translation? • In what parts of the cell does transcription and translation occur in prokaryotes? • In what parts of the cell does transcription and translation occur in eukaryotes? • Put in order of amount of DNA (from least to most): onion, human, salamander, fruit fly. • Put in order of percentage of coding DNA (from least to most): E.coli, human, round worm, fruit fly • What enzyme is used in transcription?
Transcription Watch this video: http://www.youtube.com/watch?v=WsofH466lqk Transcription: • Recognize and bind: The part of the DNA where transcription occurs is the transcription unit. A promoter site is made: TATA box + transcription factors. RNA polymerase binds to the promoter site with other transcription factors. Energy (ATP) is added. • Transcribe: The RNA polymerase starts transcribing the RNA from the DNA. When transcription starts, the transcription factors are released. The RNA is now called mRNA because it is now carrying the message to make a protein. • Terminate: When the end of the transcription unit is reached (the termination sequence), the RNA polymerase leaves, and the new strand of mRNA is released.
Transcription: mRNA nucleotides Remember:
TRANSCRIPTION SEQUENCE Re-write on board:
Translation Watch this video: http://www.youtube.com/watch?v=5bLEDd-PSTQ Translation: • Recognize and initiate protein building: The ribosome and tRNA bind to the AUG initiation (start) site. AUG codes for Methionine. AUG is always the START sequence for protein translation. Methionine can be seen on the tRNA. • Elongate: Each 3 bases, after the AUG (start codon) from the mRNA, codes for an amino acid on the tRNA. These amino acids elongate like a chain as each tRNA transfers the amino acid from the tRNA in the P site to the tRNA in the A site. • Terminate: The complex reaches a STOP codon. Everything dissociates and the polypeptide chain (protein) is made.
TRANSCRIPTION SEQUENCE Re-write on board:
Now, it’s your turn to make Protein! Try Worksheets 2 and 3 from the website! Worksheet 3 is a little difficult, but you can do it!
Midterm Exams • Please check your score! Thank you!