chapter 4

Question 1

Which mode of inheritance results in both alleles being detected equally in the heterozygous phenotype?

Answer 1

codominance

Question 2

A mutation results in an enzyme that is partially active compared to the wild-type allele. This type of “leaky” mutation is classified as

Answer 2

hypomorphic

Question 3

Which mode of inheritance results in the phenotype of a heterozygote being indistinguishable from that of an organism homozygous for the dominant allele?

Answer 3

complete dominance

Question 4

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?

Answer 4

hypermorphic

Question 5

You cross a pure-breeding white flower with a pure-breeding red flower, and the offspring are all pink. This is an example of what type of inheritance?

Answer 5

incomplete dominance

Question 6

You cross a pure-breeding white flower with a pure-breeding red flower, and the offspring are white with red spots. This is an example of what type of inheritance?

Answer 6

codominance

Question 7

Which antigen, expressed on the surface of all red blood cells, is modified by A- or B-transferases?

Answer 7

H antigen

Question 8

IA and IB alleles exhibit ________ over the i allele.

Answer 8

complete dominance

Question 9

If two alleles of a gene (T1 & T2) are incompletely dominant, then selfing individuals that are heterozygous for these two alleles will produce what phenotypic ratios among the progeny

Answer 9

1:2:1

Question 10

variable expressivity

Answer 10

A single genotype produces a range of phenotypes that differ in the degree or magnitude of expression of the particular trait specified by the gene.

Question 11

Gene interactions in which an allele of one gene modifies or prevents expression of alleles of another gene is known as

Answer 11

epistasis