Biology Test Biology Genetics & Evolution 4

Question 1

In X-linked recessive inheritance, why are males more commonly affected than females?

Accepted Answer

Males lack a second X chromosome that could carry a dominant allele

Answer

Males have only one X chromosome (hemizygous), so a single recessive allele on that X is expressed without a dominant allele on a second X to mask it.

Question 2

What is genetic drift, and which population is most affected by it?

Accepted Answer

Random allele frequency changes; affects small populations most

Answer

Genetic drift is random fluctuation in allele frequencies, and its effects are most pronounced in small populations where chance events have a larger proportional impact.

Question 3

What is the central dogma of molecular biology?

Accepted Answer

DNA → RNA → Protein

Answer

The central dogma describes the flow of genetic information: DNA is transcribed into RNA, which is then translated into protein.

Question 4

Which of the following is an example of convergent evolution?

Accepted Answer

Dolphins and sharks having similar streamlined body shapes

Answer

Dolphins and sharks independently evolved similar streamlined shapes due to similar aquatic environments, not common ancestry.

Question 5

A scientist observes that a population of beetles has become resistant to an insecticide over 20 generations. This is best explained by:

Accepted Answer

Natural selection acting on pre-existing genetic variation

Answer

Pre-existing genetic variation for resistance allows individuals carrying resistance alleles to survive and reproduce, shifting allele frequencies via natural selection.

Biology Practice Test

Biology Practice Test

Biology Test Biology Genetics & Evolution 4