Ch 14, 22, Review Answers rev 11/14/02
1 A 9 purple to 7 white phenotype in sweetpeas in the F2 generation is due to epistasis
Use the choices shown below to answer the following question(s). Each choice may be used once, more than once, or not at all.
1. Huntington's disease
2. Tay-Sachs disease
3. phenylketonuria
4. hemophilia
5. sickle-cell anemia
3 Effects of this recessive single gene can be completely overcome by regulating the diet of the affected individual. 3
5 Individuals with this disorder are unable to metabolize gangliosides, which affects proper brain development. Affected individuals die in early infancy. 2
7 A man is brought to court in a paternity case. The alleged father has blood group B, Rh positive. The mother has blood group A, Rh negative. Which blood group of the child will exclude the alleged father from possible paternity? None of these choices will exclude the man from possible paternity.
9 Which of the following statements is true regarding genomic imprinting? (A) It explains cases where the gender of the parent from whom an allele is inherited affects the expression of that allele.(B) It is greatest in females because of the larger maternal contribution of cytoplasm. (C) It may explain the transmission of Duchenne's muscular dystrophy. (D) It explains sex-linked inheritance in which the sex of the parent carrying the mutant allele determines whether male or female offspring will be affected. (E) It is found in X-inactivation in human females during early embryonic development.
11 The following is a list of chromosomal alterations. Which one of these would automatically cause two of the others?. nonreciprocal translocation
13 Fragile-x syndrome is more common in males than in females. One explanation for this is genomic imprinting by the mother.
15 A mammalian zygote with which of the following chromosomal abnormalities will NEVER develop into a viable embryo? YO
17 What does independent assortment refer to? . the random arrangement of chromosomal tetrads at metaphase I
19 Which of the following is associated with being a metafemale? an extra sex chromosome
21 The frequency of crossing over between any two linked genes is proportional to the distance between them.
23 A man who carries an X-linked allele will pass it on to all of his daughters.
25 Which of the following is a sex-influenced trait? male-pattern baldness
27 Thomas Hunt
Morgan is best remembered for his discovery and explanation of sex-linkage
29 If a pair of
homologous chromosomes fail to separate during anaphase of meiosis I, what will
be the chromosomes number (N) of the four resulting gametes? N+1; N+1; N1; N1
31 A man is brought to court in a paternity case. The alleged father has blood group B, Rh positive. The mother has blood group A, Rh negative. Which blood group of the child will exclude the alleged father from possible paternity? none
33. Kleinefelter's syndrome results from a zygote having XXY
35 If a normal human egg is fertilized by a sperm lacking the sex chromosome, the offspring will show a combination of defects known as Turner syndrome
ch 21 Web Extras from handout
37 All of the following are facts or inferences of natural selection there is heritable variation among individuals, since only a fraction of offspring survive, there is a struggle for limited resources. , individuals whose inherited characteristics best fit them to the environment will leave more offspring. ,unequal reproductive success leads to adaptations.
39 What may cause a gene pool to move and shift randomly and by chance? genetic drift
41 Natural selection is most closely related to differential reproductive success.
43 Which of the following is one important evolutionary feature of the diploid condition? Diploid organisms express less of their genetic variability than haploid organisms.
45 What can cause change in allelic frequencies due to an influx of new members into a population? gene flow
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