5-10-18 Understanding Inheritance – Punnett Squares Practice

Do Now: Take out your homework Do Now: Take out your homework. Think, Pair, Share – Think about the following questions, pair up with a shoulder partner, and share your ideas. What task do Punnett squares help plant and animal breeders accomplish? They can help predict how often specific traits will occur in offspring. What does a ratio of 2:1 mean? A ratio of 2:1 means that the first outcome should appear twice as often as the second outcome.

Punnett Square Practice Problems Genotype = 0:2:2 (GG:Gg:gg) Phenotype = 2:2 (green peas:yellow peas) G g g Gg gg

Punnett Square Practice Problems 2. Genotype = 2:2:0 (TT:Tt:tt) Phenotype = 4:0 (Tall:short) T T T t TT Tt

Punnett Square Practice Problems 3. Genotype = 0:2:2 (TT:Tt:tt) Phenotype = 2:2 (Tall:short) T t t Tt tt

Punnett Square Practice Problems 4. Genotype = 0:2:2 (RR:Rr:rr) Phenotype = 2:2 (red:white) R r r Rr rr

Punnett Square Practice Problems 5. Genotype = 0:0:4 (RR:Rr:rr) Phenotype = 0:4 (red:white) r r r rr

Punnett Square Practice Problems 6. Genotype = 4:0:0 (BB:Bb:bb) Phenotype = 4:0 (black:other color) B B B BB

Punnett Square Practice Problems 7. Homozygous brown mouse = BB Heterozygous brown mouse = Bb Offspring Genotypes: BB = 50% Bb = 50% Offspring Phenotypes: Brown fur = 100% B B B b BB Bb

Punnett Square Practice Problems 8. Heterozygous white rabbit = Ww Offspring Genotypes: WW = 25% Ww = 50% ww = 25% Offspring Phenotypes: White fur = 75% Brown fur = 25% W w W w WW Ww ww

Punnett Square Practice Problems 9. Heterozygous red flowers = Rr Offspring Genotypes: RR = 25% Rr = 50% rr = 25% Offspring Phenotypes: Red flower = 75% White flower = 25% R r R r Rr rr

Punnett Square Practice Problems 10. Homozygous tall plant = TT Heterozygous tall plant = Tt Offspring Genotypes: TT = 50% Tt = 50% Offspring Phenotypes: Tall = 100% T T T t TT Tt

Punnett Square Practice Problems 11. Heterozygous white rabbit = Ww Homozygous black rabbit = ww Offspring Genotypes: Ww = 50% ww = 50% Offspring Phenotypes: White fur = 50% Black fur = 50% W w w Ww ww

Quiz on Monday, 5/14 Vocabulary Punnett Squares Pedigrees Disregard the terms incomplete dominance, codominance, & polygenic inheritance. We’re not going to get to cover those terms and how some traits don’t follow Mendelian inheritance. Punnett Squares Pedigrees

Skill Practice: Review T T 1. 2. Tt 3. 4:0 or 1:0 (curly wings:straight wings) 4. All offspring will have curly wings. None of the offspring will have straight wings. 5. No; the results of the Punnett square will be the same, no matter where the parent genotypes are located. 6. The phenotypic ratios of the offspring will be 3:1 (curly wings:straight wings). t Tt T t T t TT Tt tt

Key Concept Builder Review 1. 2. 3. purple—100 percent; white—0 percent 4. purple—75 percent; white—25 percent 5. 3:1 6. (did not go over in class) a model showing the phenotypes of related family members that can help determine their genotypes r Rr R r R r RR Rr rr

HW Review (5th Period) Rr r r R 1. Every plant will have red kernels. The ratio of plants with red kernels to plants with white kernels would be 4:0. r r R Rr

HW Review (5th Period) 3. The plants would be a mixture of those with red kernels and those with white kernels. 4. The ratio would be 3:1. That means 75 percent of the offspring would have red kernels and 25 percent would have white kernels. R r R r RR Rr rr

Independent Practice: Punnett Square Problems Complete the problems on the Punnett Square Worksheet. For 12 minutes, silently work on the problems. When instructed, pair up your shoulder partner and share your answers.