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Block Day- April 25, 2012

Block Day- April 25, 2012. Homework: none Make an entry- Entry 41: Heredity and Genetics2 - 4/25/12 See attached entry. Symbols used for alleles. The traditional symbols used for alleles are big and small letters The letter chosen usually refers to the dominant allele

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Block Day- April 25, 2012

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  1. Block Day- April 25, 2012 Homework: none Make an entry- Entry 41:Heredity and Genetics2- 4/25/12 See attached entry

  2. Symbols used for alleles • The traditional symbols used for alleles are big and small letters • The letter chosen usually refers to the dominant allele Example: R = Red allele r = Blue allele

  3. The combination of alleles determines the observed characteristics RED allele BLUE allele RED allele BLUE allele BLUE allele RED allele Chromosome combination Allele combination red, red red, blue (or blue, red) blue, blue Observed characteristic RED RED BLUE

  4. The combination of alleles determines the observed characteristics R R R r r r Chromosome combination Allele combination RR Rr rr Observed characteristic RED RED BLUE

  5. The combination of alleles determines the observed characteristics R R R r r r Chromosome combination GENOTYPE RR Rr rr PHENOTYPE RED RED BLUE

  6. Homozygous – the two alleles are the same • RR and rr are homozygous genotypes Heterozygous – the two alleles are different • Rr is a heterozygous genotype

  7. Draw the enzymes and pigment molecules present in the cells of each type of flower below. GENOTYPE for flower type 2: Allele of chromosome 2A= Y1 (functional enzyme) Allele of chromosome 2B= Y2 (non-functional enzyme) 2A 2B Y1 Y2 1A 1B WHAT DOES RrACTUALLY MEAN? nucleus R r Yes or no, is any functional enzyme Y in the cell? PHENOTYPE of flower type 2: RED YES

  8. Possible combinations of inherited chromosomes/genes Dad Mom Parents R r R r X R R Possible Offspring Order doesn’t matter, these two are the same (Rr) R r r R r r What are all possible genotypes produced from the parents? RR, Rr, rr

  9. Punnett squares organize all possible offspring combinations Dad Mom R r R r X R r R RR Rr r Rr rr

  10. R= red flower allele r= blue flower allele Genotypic ratio = 1RR: 2Rr:1rr 1 out of 4 possibilities is rr = What is probability of Rr? • How many out of 4 are red? • What is the probability of red? • What is the probability of blue? Phenotypic ratio = 3 Red:1 blue 25 % 50 % 3/4 75 % 25 %

  11. Your turn: • What are all possible genotypes and phenotypes produced by crossing Rr with rr? Complete the Punnett Square

  12. Punnett squares predict ratios of all genotypes and phenotypes produced Genotypic ratio = 2 Rr:2 rr or 1Rr : 1 rr Phenotypic ratio = 2 Red:2 Blue or 1 Red : 1 Blue R= red flower allele r= blue flower allele

  13. Punnett square practice Calculate the predicted genotypic and phenotypic ratios • Hh X HH H(hairy) is dominant over h(not hairy) 2a) Gg X gg G(green sepals) is dominant over g(yellow sepals) 2b) What would the cells of the green and yellow plants look like? (functional vs non-functional)

  14. Genotypic ratio = 2 HH:2 Hh or 1HH : 1Hh Phenotypic ratio = 4 Hairy: 0 Non-hairy

  15. Genotypic ratio = 2 Gg:2 gg or 1Gg : 1gg Phenotypic ratio = 2 Green: 2 Yellow or 1 Green : 1 Yellow

  16. Yes or no, is any functional enzyme C in the cell? GENOTYPE for Green Flower (Gg) : YES Allele of chromosome A= C1 (functional enzyme) A Y1 B Y2 Allele of chromosome B= C2 (non-functional enzyme) 1A PHENOTYPE of flower type 2: 1B nucleus Green Yes or no, is any functional enzyme Y in the cell? GENOTYPE for yellow flower (gg): A Y2 NO Y2 1A Allele of chromosome A= C2 (non-functional enzyme) B 1B nucleus PHENOTYPE of flower type 3: Allele of chromosome B= C2 (non-functional enzyme) Yellow

  17. Make an entry- Entry 42: Punnett Square Worksheet- 4/25/12 See attached entry

  18. #1 In rabbits, black fur is dominant over white fur. Show the cross of a heterozygous black male with a homozygous white female. • Parents: Bb x bb b b • Genotypic Ratio: B   1 Bb : 1bb • Phenotypic Ratio: b 1 black: 1 white

  19. #2 Tall is dominant over short in pea plants. Show the cross of a homozygous short plant is crossed with a homozygous tall plant. • Parents: tt x TT • Genotypic Ratio:   4 Tt (or 100% Tt) • Phenotypic Ratio: All or 100% Tall T T t t

  20. # 3 In humans, free-ear lobes are dominant to attached ear lobes. Two parents that are both heterozygous free are expecting a child. What are the chances that the child will have free ear lobes of attached? • Parents: Ff x Ff   F f • Genotypic Ratio: F   1 FF:2Ff: 1ff • Phenotypic Ratio: f 3 Free: 1 attached

  21. #4 S=smooth s= wrinkled Parents: ss x Ss Genotypic ratio: 2 Ss:2 ss Phenotypic ratio: 2 smooth: 2 wrinkled

  22. #5 S=smooth s= wrinkled Parents: Ss x Ss Genotypic ratio: 1 SS: 2Ss: 1ss Phenotypic ratio: 3 smooth: 1 wrinkled

  23. #6 B=blue eyes b=red eyes Parents: Bb x bb Genotypic ratio: 2 Bb: 2 bb Phenotypic ratio: 2 blue eyes: 2 red eyes

  24. #7 R= red eyes r= white eyes Parents: rr x rr Genotypic Ratio: 4 rr or all rr Phenotypic: 4 white eyes or all white eyes

  25. #8 A homozygous dominant brown mouse is crossed with a heterozygous brown mouse (tan is the recessive color). • Parents: BB x Bb B b • Genotypic Ratio: B   1 BB : 1Bb • Phenotypic Ratio: B All Brown or 4 Brown: 0 Tan

  26. #9 Two heterozygous white (brown fur is recessive) rabbits are crossed. • Parents: Ww x Ww Genotypic Ratio: 1WW:2Ww:1ww • Phenotypic Ratio: 3 WHITE: 1 BROWN W w W w

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