Genetics Test 3 Ch. 4 Flashcards
1) Which mode of inheritance produces heterozygotes with phenotypes that differ from either homozygote but typically more closely resembles one homozygous phenotype than the other?<br></br>A) complete dominance<br></br> <br></br>B) incomplete dominance<br></br>C) codominance<br></br>D) epistasis<br></br>E) incomplete penetrance
Answer: B
2) Which mode of inheritance results in the phenotype of a heterozygote being indistinguishable from that of an organism homozygous for the dominant allele?<br></br>A) complete dominance<br></br>B) incomplete dominance<br></br>C) codominance<br></br>D) epistasis<br></br>E) incomplete penetrance
Answer: A
3) Which mode of inheritance results in both alleles being detected equally in the heterozygous phenotype?<br></br>A) complete dominance<br></br>B) incomplete dominance<br></br>C) codominance<br></br>D) epistasis<br></br>E) incomplete penetrance
Answer: C
4) A mutation results in an enzyme that is partially active compared to the wild- type allele. This type of “leaky” mutation is classified as ________.<br></br>A) null/ amorphic<br></br>B) hypomorphic<br></br>C) hypermorphic<br></br>D) neomorphic<br></br>E) dominant negative
Answer: B
5) A mutation resulting in an inactive gene product is classified as ________. <br></br>A) null/ amorphic<br></br>B) hypomorphic<br></br>C) hypermorphic<br></br>D) neomorphic<br></br>E) dominant negative
Answer: A
6) Two proteins interact to form a multimeric complex. When one of the proteins is mutated, there is a substantial loss of functional activity in the multimeric protein. This type of mutation is classified as ________.<br></br>A) null/ amorphic<br></br>B) hypomorphic<br></br>C) hypermorphic<br></br>D) neomorphic<br></br>E) dominant negative
Answer: E
7) Many oncogenes result from mutations that cause excessive expression of a protein in cells where it is normally not expressed or is expressed at inappropriate times during development. This type of mutation can be described as ________.<br></br>A) hypomorphic<br></br>B) dominant negative<br></br>C) amorphic<br></br>D) hypermorphic <br></br>E) neomorphic
Answer: D
8) A mutation results in a gene product with a novel function that is not normally found in wild- type organisms. This type of mutation is known as ________.<br></br>A) dominant negative<br></br>B) hypermorphic <br></br>C) hypomorphic<br></br>D) amorphic<br></br>E) neomorphic
Answer: E
9) Which of the following is correct regarding individuals who are blood type AB?<br></br>A) Their blood cells clump when they receive blood from an individual with the genotype IAi.<br></br>B) They express B- transferase that adds N- acetylgalactosamine to the H antigen.<br></br>C) They do not carry the A or B antigen.<br></br>D) They are the universal recipients.<br></br>E) They carry both the anti- A and anti- B antibodies.
Answer: D
10) A man with blood type A (whose mother was blood type O) has children with a woman that has blood type AB. The man and the woman are also heterozygous for the H antigen. What is the probability that they will have a child with blood type A?<br></br> A) 0 B) 1/8 C) 3/4 D) 1/2 E) 3/8
Answer: E
12) What type of allele is often detected as a distortion in segregation ratios, where one class of expected progeny is missing?<br></br>A) incompletely penetrant allele <br></br>B) partially dominant allele<br></br>C) dominant negative allele<br></br>D) temperature- sensitive allele<br></br>E) lethal allele
Answer: E
13) You discover a new allele of a gene important for tail formation in mice. WT mice have long tails, but mice heterozygous for the allele have short tails. When you cross two heterozygous mice together, you obtain a 2:1 ratio of short- tailed mice to long- tailed mice. None of the short- tailed progeny are homozygous. What type of allele results in short tails?<br></br>A) temperature- sensitive allele<br></br>B) lethal allele<br></br>C) incompletely penetrant allele<br></br>D) partially dominant allele<br></br>E) dominant negative allele
Answer: B
14) The amount of enzyme activity in a cell that is homozygous for a mutant allele is 400 units. The amount of enzyme activity in a cell homozygous for the WT allele is 200 units. The amount of enzyme activity in a heterozygote is 300 units. What type of allele is the mutant allele?<br></br>A) hypermorphic<br></br>B) hypomorphic <br></br>C) neomorphic<br></br>D) null/ amorphic<br></br>E) dominant negative
Answer: A
15) The amount of enzyme activity in a cell that is homozygous for a mutant allele is 400 units. The amount of enzyme activity in a cell homozygous for the WT allele is 200 units. The amount of enzyme activity in a heterozygote is 300 units. What is the dominance relationship between the WT and mutant allele for the phenotype of amount of enzyme per cell? <br></br>A) The WT and mutant alleles show incomplete dominance.<br></br>B) The mutant allele is dominant.<br></br>C) The WT allele is dominant.<br></br>D) The WT and mutant alleles are codominant.<br></br>E) It is impossible to determine from the information given.
Answer: A
16) The amount of enzyme activity in a cell that is homozygous for a mutant allele is 0 units. The amount of enzyme activity in a cell homozygous for the WT allele is 200 units. The amount of enzyme activity in a heterozygote is 0 units. What type of allele is the mutant allele?<br></br>A) neomorphic<br></br>B) hypermorphic<br></br>C) hypomorphic<br></br>D) null/ amorphic<br></br>E) dominant negative
Answer: E
17) Which phenomenon explains differences in the inheritance patterns of the appearance of a chin beard between males and females of certain species of goats, even when their genotypes are the same?<br></br>A) sex- limited trait<br></br>B) lethal allele<br></br>C) sex- influenced trait<br></br>D) incomplete penetrance<br></br>E) variable expressivity
Answer: C
18) In certain goat breeds, appearance of a chin beard is a sex- influenced trait. Recall that bearding is inherited as an autosomal trait determined by two alleles, B1 and B2, and females must be homozygous for the bearded allele, B2, to have a beard. What genotypes must a bearded billy goat (male) and a beardless female goat have if they have a bearded female offspring?<br></br>A) The bearded billy goat must be heterozygous for the bearded allele, while the beardless female must be homozygous for the bearded allele.<br></br>B) The bearded billy goat could be heterozygous or homozygous for the bearded allele, while the beardless female must be homozygous for the bearded allele.<br></br>C) Both the bearded billy goat and beardless female must be heterozygous for the bearded allele.<br></br>D) The bearded billy goat could be heterozygous or homozygous for the bearded allele, while the beardless female must be heterozygous for the bearded allele.<br></br>E) Both the bearded billy goat and beardless female must be homozygous for the bearded allele.
Answer: D
21) King George III of England and other members of the royal family were afflicted with a series of strange, seemingly unrelated symptoms including abdominal pain, rapid pulse, convulsions, and insanity. It has been determined that he likely suffered from porphyria, caused by a mutation in a single allele. What is the genetic term describing the alteration of multiple, distinct traits of an organism by a mutation in a single gene?<br></br>A) incomplete dominance<br></br>B) pleiotropy<br></br>C) epistasis<br></br>D) codominance<br></br>E) incomplete penetrance
Answer: B