1. When a pure-breeding wild-type flower having red flowers is crossed with a pure-breeding mutant line having white petals, the F1 generation has pink petals. After self-crossing the F1 generation, you observe the phenotypic ratio of the F2 offspring as 1 red: 2 pink: 1 white. Which type of dominance is portrayed here, and how can it best be explained at a molecular level?
a) codominance; number of doses of wild-type allele determines concentration of a chemical made by the proteinb) codominance; each allele determines the presence of a specific phenotypec) incomplete dominance; number of doses of wild-type allele determines concentration of a chemical made by the proteind) incomplete dominance; each allele determines the presence of a specific phenotype2. Which of the following is not a situation in which a loss-of-function allele may be dominant to the wildtype allele?a) the wildtype allele is haplosufficientb) the wildtype allele is haploinsufficientc) the loss-of-function protein forms a nonfunctional complex with the wildtype protein d) the loss-of-function protein competes with the wildtype protein to bind a DNA target e) the loss-of-function protein sequesters a substrate
- 2 months ago
Question 1: Answer B
Question 2: Answer A
Q1 is codominance since both the wild type and the variant are expressed in the pink flowers. It is not A since the dosage of the wild type chemical alone does not account for a mixing of colours.
Q2 is haplosufficient: a single copy of the wild type is enough to produce the functional protein which is not an instance where there mutant variant is dominant.
Whoever wrote those questions is a real piece of work. Tricking students with double negatives and wordplay does not make the question in any way more educational.