Genetics and Evolution Flashcards
7 cards from real OAT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Genetics and Evolution flashcards as text
In incomplete dominance, two homozygous parents (red × white flowers) produce offspring with pink flowers. When the pink offspring are crossed together, what phenotypic ratio is expected in the F2 generation?
Answer: 1 red : 2 pink : 1 white
Crossing heterozygotes (Rr × Rr) in an incomplete dominance system yields 1 RR (red) : 2 Rr (pink) : 1 rr (white) because neither allele fully masks the other.
Which of the following best describes epistasis?
Answer: One gene's alleles masking or modifying the expression of a different gene
Epistasis occurs when the alleles at one gene locus affect the phenotypic expression of a separate gene locus, altering expected Mendelian ratios.
What is the Hardy-Weinberg equation used to calculate?
Answer: The expected allele and genotype frequencies in a non-evolving population
The Hardy-Weinberg equation (p² + 2pq + q² = 1) predicts genotype frequencies under the assumption of no evolution (no selection, drift, gene flow, or mutation).
Sickle cell anemia is an autosomal recessive disorder. Two carriers have children together. What fraction of their children would be expected to be carriers but unaffected?
Answer: 1/2
A cross between two carriers (Aa × Aa) yields 1/4 AA : 2/4 Aa : 1/4 aa; exactly half (2/4) of the offspring are expected to be carriers (Aa) and phenotypically unaffected.
Which process generates the greatest genetic diversity during sexual reproduction?
Answer: Independent assortment and crossing over during meiosis
Independent assortment and crossing over during meiosis shuffle alleles into new combinations, producing gametes with unique genetic compositions that drive diversity.
According to Darwin's theory of natural selection, which individuals are most likely to contribute offspring to the next generation?
Answer: Individuals with traits best suited to their environment
Natural selection favors individuals with heritable traits that increase their reproductive success in their current environment, allowing those traits to increase in frequency.
A gene has two alleles with frequencies p = 0.7 and q = 0.3 in a population at Hardy-Weinberg equilibrium. What is the expected frequency of heterozygotes?
Answer: 0.42
The frequency of heterozygotes is 2pq = 2(0.7)(0.3) = 0.42 according to the Hardy-Weinberg equation.