AP Biology Unit 5 Questions and Answers Already Passed

AP Biology Unit 5 Questions and Answers Already Passed ) Between which two genes would you expect the highest frequency of recombination? A) A and W B) W and E C) E and G D) A and E E) A and G Answer: E 10) Cinnabar eyes is a sex-linked recessive characteristic in fruit flies. If a female having cinnabar eyes is crossed with a wild-type male, what percentage of the F1 males will have cinnabar eyes? A) 0% B) 25% C) 50% D) 75% E) 100% Answer: E 13) Sex determination in mammals is due to the SRY region of the Y chromosome. An abnormality of this region could allow which of the following to have a male phenotype? A) Turner syndrome, 45, X B) translocation of SRY to an autosome of a 46, XX individual C) a person with an extra X chromosome D) a person with one normal and one shortened (deleted) X E) Down syndrome, 46, XX Answer: B 14) In humans, clear gender differentiation occurs, not at fertilization, but after the second month of gestation. What is the first event of this differentiation? A) formation of testosterone in male embryos B) formation of estrogens in female embryos C) anatomical differentiation of a penis in male embryos D) activation of SRY in male embryos and masculinization of the gonads E) activation of SRY in females and feminization of the gonads Answer: D 15) A triploid cell contains three sets of chromosomes. If a cell of a usually diploid species with 42 chromosomes per cell is triploid, this cell would be expected to have which of the following? A) 63 chromosomes in 31 1/2 pairs B) 63 chromosomes in 21 sets of 3 C) 63 chromosomes, each with three chromatids D) 21 chromosome pairs and 21 unique chromosomes B) 63 chromosomes in 21 sets of 3 15) Duchenne muscular dystrophy (DMD) is caused by a gene on the human X chromosome. The patients have muscles that weaken over time because they have absent or decreased dystrophin, a muscle protein. They rarely live past their 20s. How likely is it for a woman to have this condition? A) Women can never have this condition. B) One-half of the daughters of an affected man could have this condition. C) One-fourth of the children of an affected father and a carrier mother could have this condition. D) Very rarely would a woman have this condition; the condition would be due to a chromosome error. E) Only if a woman is XXX could she have this condition. Answer: D 16) Women (and all female mammals) have one active X chromosome per cell instead of two. What causes this?