OAT Genetics and Evolution 3

Question 1

Which of the following describes allopatric speciation?

Accepted Answer

A population divides into two species due to physical geographic barriers

Answer

Allopatric speciation occurs when a geographic barrier physically separates a population into two isolated groups that diverge genetically until they can no longer interbreed.

Question 2

A deletion of one nucleotide in the middle of a coding sequence would most likely cause which type of mutation?

Accepted Answer

Frameshift mutation altering all downstream codons

Answer

Deleting a single nucleotide shifts the reading frame for all codons downstream, typically resulting in a completely different and usually non-functional protein.

Question 3

Which of the following is NOT a condition required to maintain Hardy-Weinberg equilibrium?

Accepted Answer

Small population size

Answer

Hardy-Weinberg equilibrium requires a large (ideally infinite) population; small population size promotes genetic drift, which is an evolutionary force that disrupts equilibrium.

Question 4

In a dihybrid cross between two AaBb parents, what is the expected ratio of offspring showing both dominant phenotypes (A_B_)?

Accepted Answer

9/16

Answer

In a dihybrid cross (AaBb × AaBb) with independent assortment, 9 of 16 offspring are expected to show both dominant phenotypes (A_B_), giving a 9:3:3:1 ratio.

Question 5

Mitochondrial DNA is primarily inherited from:

Accepted Answer

The mother only

Answer

Mitochondria are inherited maternally because the egg contributes almost all the cytoplasm to the zygote, while sperm contribute little to no cytoplasm.

OAT - Optometry Admission Test Practice Test

OAT - Optometry Admission Test Practice Test

OAT Genetics and Evolution 3