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PRACTICE TEST – UNIT E1. In Mendel's "Experiment 1," true-breeding pea plants with spherical seeds were crossed with true-breeding plants with dented seeds. (Spherical seeds are the dominant characteristic.) Mendel collected the seeds from this cross, grew F1-generation plants, let them self-pollinate to form a second generation, and analyzed the seeds of the resulting F2 generation. The results that he obtained, and that you would predict for this experiment are:1/2 the F1 and 3/4 of the F2 generation seeds were spherical.1/2 the F1 and 1/4 of the F2 generation seeds were dented.All of the F1 and F2 generation seeds were spherical.All the F1 and 3/4 of the F2 generation seeds were spherical.2. A genetic cross between two F1-hybrid pea plants having yellow seeds will yield what percent green-seeded plants in the F2 generation? Yellow seeds are dominant to green.0%25%50%100%3. To identify the genotype of yellow-seeded pea plants as either homozygous dominant (YY) or heterozygous (Yy), you could do a test cross with plants of genotype _______.yYyyYY4. Hemophilia in humans is due to an X-chromosome mutation. What will be the results of mating between a normal (non-carrier) female and a hemophilac male?half of daughters are normal and half of sons are hemophilic.all sons are normal and all daughters are carriers.half of sons are normal and half are hemophilic; all daughters are carriers.all daughters are normal and all sons are carriers.5. Which of the following genetic crosses would be predicted to give a phenotypic ratio of 9:3:3:1?SSYY x ssyySsYY x SSYySsYy x SsYySSyy x ssYY6. In some cattle the genes for brown hair (B) and for white hair (W) are co-dominant. Cattle with alleles for both brown and white hair, have both brown and white hairs. This condition gives the cattle a reddish color, and is referred to as Roan (BW).?If a roan cow and a white bull?are crossed what is the genotype ratio?50% BW / 50% WW75% BW / 25% WW0% BW / 100% WW25% BB / 75% BWThe following is a pedigree chart traces disease “z”Figure 17. Based on Figure 1, which of the following statements is FALSE?Only males are affectedThe disease “z” may be sex-linked Females are affected by disease “z”Half of the first generation is affected8. In mice the ability to run normally is a dominant trait. Mice with this trait are called running mice (R), the recessive trait causes mice to run in circles only. Mice with this trait are called waltzing mice (r). Hair color is also inherited in mice. Black hair (B) is dominant over brown hair (b). If a heterozygous running, heterozygous black mouse with a homozygous running, homozygous black mouse are crossed, what is the resulting phenotype?100% waltzing black100% running black25% running brown75% waltzing brown9. A human female "carrier" who is heterozygous for the recessive, sex-linked trait red color blindness, marries a normal male.What proportion of their female progeny will show the trait?All1/21/4010. The alleles for eye color and for body color are on the X chromosome of Drosophila, but not on the Y. Red eye color (w+) is dominant to white eye color (w), and tan body color (y+ ) is dominant to yellow body color (y).What is the genotype of a tan-bodied, white-eyed male?Xw+y+ YXwy+ YXwy YXw+y Y11. In some cats the gene for tail length shows incomplete dominance. Cats with long tails and cats with no tails are homozygous for their respective alleles. Cats with one long tail allele and one no tail allele have short tails. If a long tail cat and a short tail cat?are crossed, what percentage of the offspring will have short tails?0%25%50% 100%12. Traits produced by two or more genes, such as height in humans, are calledpolygenickaryotypegametogenesisassorted??13. What is the missing genotype of the punnett square on Figure 2?RrTTrrTtRRTtRrTt14. In Mendel's experiments, if the gene for tall (T) plants was dominant over the gene for short (t) plants, what would be the result of crossing one heterozygous plant and one homozygous dominant plant?1/2 would be tall; 1/2 short3/4 would be tall; 1/4 short.1/2 would be tall; 3/4 short.All the offspring would be tall.15. What are the possible blood types of the offspring of a cross between individuals that are type AB and type O? (Hint: blood type O is recessive)AB or OA, B, or OA or BA, B, AB, or O16. Two heterozygous parents cross. Each has a dominant allele B for brown eyes and a recessive gene b for blue eyes. The phenotypic ratio for brown:blue eyes in their offspring is1:2:13:19:31:3:117. Someone who is heterozygous for a recessive allele that causes a disorderis not a carrier of the disorderwill not have the disordercannot have offspring with the disorderwill get the disorder later in life18. Suppose you conduct a cross between two plants with light purple flowers. Your results show that 25% of the offspring have white flowers, 25% have dark purple flowers, and 50% have light purple flowers. Which of the following patterns of inheritance explains these results?dominanceincomplete dominancecodominancemultiple alleles19. As a person gets older, their skin color gets darker, this change in phenotype is most likely due toEnvironmental factorsDNA mutationsChanges in genotypeAging factors20. Down syndrome is characterized by having an extra copy of at least a portion of chromosome 21. Which of the following methods would quickly identify the disorder?pedigree chartkaryotypemeiosis maplinkage mapFigure 3.The pedigree in Figure 3 shows the inheritance of free earlobes and attached earlobes in five generations of a family. Attached earlobes are caused by a recessive allele (f). 21. What is the genotype for individual 2?FFffFfFff22. What is the genotype and phenotype of individual 14?ff; attached earlobesFf; attached earlobesff; detached earlobesFF; detached earlobes23. If a mother has blood type A and a father has type blood AB, which of the following blood type is not possible for their children?type Atype Btype ABtype O24. A roan (white and red) horse mates with a white horse, what will be the phenotypic ratio of the offspring1 red: 2 white1 red: 1 roan1 white: 1 roan2 white: 2 red25. The table lists the trials for fruit color where allele R exhibits incomplete dominance over allele R'.?Heterozygous fruit have orange phenotypes. What percent of offspring are expected to have an orange phenotype if the parent plants are orange (RR') and yellow (R'R')?A. 25%B. 50%C. 75%D. 100%26. A human baby boy inherits a recessive allele from his mother. In which circumstance would he most likely show the trait coded for by the recessive allele?A. The baby inherits the dominant allele from his father. B. The allele is on an autosomal chromosome and the baby is a twin. C. The allele is on the X chromosome.D. The allele is on the Y chromosome. 27. Hitchhiker's thumb (H) is dominant to no hitchhiker's thumb (h). A woman who does not have hitchhiker's thumb marries a man who is heterozygous for hitchhiker's thumb. What is the probable genotypic ratio of their children??A. 0% Hh: 100% hhB. 50% Hh: 50% hhC. 75% Hh: 25% hhD. 100% Hh: 0% hh28. One of the parents of a child has phenylketonuria (PKU), which is caused by recessive alleles. The other parent does not have the PKU alleles. What is the chance that the couple will have a child with phenylketonuria??A. 0%B. 50%C. 75%D. 100% ................
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