UNIT II PRACTICE Exam-C

UNIT II PRACTICE Exam-C - UNIT II PRACTICE Exam-C BSC 2011...

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UNIT II PRACTICE Exam-C BSC 2011 Spring 2008 Select the best answer to each question - answers provided at the end. 1) What is a mechanism for the production of genetic recombination (i.e., a “reshuffling” of genetic information)? A) deletions and duplications during meiosis B) methylation of cytosine C) nondisjunction D) X inactivation E) crossing over and independent assortment 2) Males are more often affected by sex-linked traits than females because___________. A) X chromosomes in males generally have more mutations than X chromosomes in females. B) males are hemizygous for the X chromosome. C) mutations on the Y chromosome often exacerbate the effects of X-linked mutations. D) male hormones such as testosterone often exacerbate the effects of mutations on the X chromosome. E) female hormones such as estrogen often compensate for the effects of mutations on the X. 3) SRY is ________. A) an autosomal gene that is required for the expression of genes on the Y chromosome. B) a gene present on the Y chromosome that triggers male development. C) required for development, and males or females lacking the gene do not survive past early childhood. D) a gene present on the X chromosome that triggers female development. E) an autosomal gene that is required for the expression of genes on the X chromosome. 4) In cats, assume the same gender-determination system as in humans. Brown eye color is caused by an X-linked allele; the other allele for this gene causes blue-colored eyes. The heterozygote condition results in green eyes. What kinds of offspring would you expect from the cross of a brown-eyed female and a blue-eyed male? A) green-eyed female; brown-eyed male B) green-eyed female; green-eyed male C) blue-eyed female; brown-eyed male D) brown-eyed female; blue-eyed male E) blue-eyed female; blue-eyed male 5) A recessive allele on the X chromosome is responsible for red-green color blindness in humans. A woman with normal vision whose father is color-blind marries a color-blind male. What is the chance that a son of this couple will be color-blind? A) 0 B) 25% C) 75% D) 100% E) 50% 6) In birds, sex is determined by a ZW chromosome scheme. Males are ZZ and females are ZW . A lethal recessive allele that causes death of the embryo is sometimes present on the Z chromosome in pigeons. What would be the expected sex ratio in the surviving offspring of a cross between a male that is heterozygous for the lethal allele and a normal female, assuming they produced many, many, MANY progeny? (Write out the key and think carefully!) A) 1:1 male to female B) 3:1 male to female C) 1:2 male to female D) 4:3 male to female E) 2:1 male to female
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Refer to the following information to answer the next THREE questions. An achondroplastic male dwarf
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This note was uploaded on 04/01/2012 for the course BSC BSC2011 taught by Professor Spears during the Spring '10 term at FSU.

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UNIT II PRACTICE Exam-C - UNIT II PRACTICE Exam-C BSC 2011...

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