UNIT II PRACTICE EXAM-D

UNIT II PRACTICE EXAM-D - UNIT II EXAM - Form A BSC 2011 -...

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UNIT II EXAM - Form A BSC 2011 - Section 02 Spring 2008 MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Males are more often affected by X-linked traits than females because _____. A) female hormones such as estrogen often compensate for the effects of mutations on the X. B) males are hemizygous for the X chromosome. C) mutations on the Y chromosome often exacerbate the effects of X-linked mutations. D) X chromosomes in males generally have more mutations than X chromosomes in females. E) male hormones such as testosterone often exacerbate the effects of mutations on the X chromosome. 2) SRY is _____. A) a gene present on the X chromosome that triggers female development. B) an autosomal gene that is required for the expression of genes on the Y chromosome. C) an autosomal gene that is required for the expression of genes on the X chromosome. D) a gene present on the Y chromosome that triggers male development. E) required for development, and males or females lacking the gene do not survive past early childhood. 3) In cats, black fur color is caused by an X-linked allele; the other allele at this locus causes orange color. The heterozygote is tortoiseshell. What kinds of offspring would you expect from the cross of a black female and an orange male? A) orange female; black male B) orange female; orange male C) black female; orange male D) tortoiseshell female; black male E) tortoiseshell female; tortoiseshell male 4) Red-green color blindness is a sex-linked recessive trait in humans. Two people with normal color vision have a color-blind son. What are the genotypes of the parents? A) X c X c and X C Y B) X c X c and X c Y C) X C X C and X c Y D) X C X c and X C Y E) X C X C and X C Y 5) 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. Which of the following statements is TRUE if a cross is made between a male that is heterozygous for the lethal allele and a normal female? A) 1/4 of the possible zygotes would die, and these would have been male B) 1/4 of the possible zygotes would die, and these would have been female C) 1/2 of all possible zygotes would die D) all female zygotes would die E) all male zygotes would die 6) A man who carries an X-linked allele will pass it on to _____. A) all of his sons B) half of his sons C) all of his children D) half of his daughters E) all of his daughters Refer to the following information to answer the next FOUR questions below. An achondroplastic male dwarf with normal vision marries a color-blind woman of normal height. The man's father was six-feet tall, and both the woman's parents were of average height. Achondroplastic dwarfism is autosomal dominant, and red-green color blindness is X-linked recessive. 7)
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UNIT II PRACTICE EXAM-D - UNIT II EXAM - Form A BSC 2011 -...

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