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Warm ups: 1. What does homozygous mean? 2. A heterozygous person who is tall has what genotype? a. Tt b. tall c. Short d. TT 3. A father is homozygous for blue eyes. (B = brown, b= blue) What is his genotype? a. Blue b. brown c. bb d. BB Bikini Bottom Genetics Punnett Square Problems #2 One of SpongeBob’s cousin, SpongeBillyBob, recently met a cute squarepants gal, SpongeGerdy, at a local dance and fell in love. Use your knowledge of genetics to answer the questions below. 1. If SpongeGerdy’s father is hybrid squarepants and her mother is a roundpants, what is her genotype? Complete the punnett square below to show the possible genotypes that would result to help you determine Gerdy’s genotype. (S = squarepants, s = roundpants) G’s father S Ss = _____ ss G’s mother = ____ Gerdy’s genotype = ____________ Ss s Ss ss s Ss ss 2. Spongebob BillyBob = Ss s 3. Complete the punnett square to show the possibiltiites that would result if Billy Bob and Gerdy had children. (S = squarepants, s = roundpants) S Ss Billy Bob = _____ Ss Gerdy = ____ s S SS Ss s Ss s s 75 % squarepants _____ 25 % roundpants _____ _____ 50 % purebred 50 % hybrid _____ 4. SpongeBob’s aunt and uncle, SpongeWilma and SpongeWilbur, have the biggest round eyes in the family. Wilma is believed to be heterozygous for her round eye shape, while Wilbur’s family brags that they are a pure line. (R = round eyes r = oval eyes) R Rr Wilma = _____ RR Wilbur = ____ r R RR Rr RR Rr 100 % round eyes _____ _____ % oval eyes 0 50 _____ % homozygous 50 _____ % heterozygous R 5. SpongeBob’s aunt is famous around town for her itty, bitty stubby nose! She recently met a cute squarepants fellow who also has a stubby noes, which is a recessive trait. Would it be possible for them to have child with a regular long nose? Why or why not? Create a punnett square to help you answer this question. (L = long nose l = stubby nose) llll Aunt = _____ l l Cute guy = ____ l 0 _____ % long nose 100 _____ % stubby nose 100 % homozygous _____ 0 _____ % heterozygous l ll ll ll ll 6. SpongeBob’s mother is so proud of her son and his new wife, SpongeSusie, as they are expecting a little sponge. She knows that they have a 50% chance of having a little roundpants, but is also hoping the new arrival will be blue (a recessive trait) like SpongeSusie and many members of her family. If SpongeBob is heterozygous for his yellow body color, what are the chances that the baby sponge will be blue? (Y = yellow, y = blue) Yy Spongebob = ___ yy Susie = ____ Y y _____ % yellow 50 50 % blue _____ 50 _____ % homozygous 50 _____ % heterozygous y Yy yy Yy yy y