Q: In a population, the frequency of allele A is $p = 0.7$ and the frequency of allele a is $q = 0.3$. According to the Hardy-Weinberg principle, what is the expected frequency of heterozygotes (Aa) in the next generation?

$2pq = 2 \times 0.7 \times 0.3 = 0.42$

Q: A population of 1000 individuals has two alleles for a gene: B and b. If the frequency of B is $p = 0.6$ and the population is in Hardy-Weinberg equilibrium, how many individuals are expected to be homozygous recessive (bb)?

$q^2 \times 1000 = (0.4)^2 \times 1000 = 0.16 \times 1000 = 160$

Question 1

Which of the following best describes the process of evolution as defined in modern biology?

Accepted Answer

A change in the frequency of heritable traits (alleles) in a population over time.

Question 2

Mendel’s principle of segregation is best explained by which cellular process?

Accepted Answer

Meiosis, during which homologous chromosomes separate so that each gamete receives only one allele.

Question 3

In a population, the frequency of allele A is $p = 0.7$ and the frequency of allele a is $q = 0.3$. According to the Hardy-Weinberg principle, what is the expected frequency of heterozygotes (Aa) in the next generation?

Accepted Answer

$2pq = 2 	imes 0.7 	imes 0.3 = 0.42$

Question 4

Which of the following is NOT an assumption of the Hardy-Weinberg equilibrium?

Accepted Answer

Natural selection favors certain alleles over others.

Question 5

A population of 1000 individuals has two alleles for a gene: B and b. If the frequency of B is $p = 0.6$ and the population is in Hardy-Weinberg equilibrium, how many individuals are expected to be homozygous recessive (bb)?

Accepted Answer

$q^2 	imes 1000 = (0.4)^2 	imes 1000 = 0.16 	imes 1000 = 160$

Question 6

Which scenario would most likely cause a population to deviate from Hardy-Weinberg equilibrium?

Accepted Answer

A small population experiences a natural disaster, randomly killing many individuals.

Question 7

Which of the following best explains why Mendel’s results did not support the blending inheritance hypothesis?

Accepted Answer

Traits disappeared in the F1 generation but reappeared in the F2 generation, indicating discrete inheritance.

Question 8

If a gene has three alleles (I$^A$, I$^B$, i) as in the ABO blood group system, how many different genotypes are possible?

Accepted Answer

Six

Question 9

Which evolutionary mechanism is the only one that can introduce new alleles into a population?

Accepted Answer

Mutation

Question 10

A population of beetles is isolated on an island. Over time, a few beetles from a neighboring island migrate and join the population, introducing new alleles. Which evolutionary process is this an example of?

Accepted Answer

Gene flow

Question 11

Which of the following is an example of codominance?

Accepted Answer

A person with AB blood type expresses both A and B antigens equally.

Question 12

Which of the following best describes pleiotropy?

Accepted Answer

A single gene affects multiple, different phenotypic traits.

Question 13

In a population, the frequency of allele D is $p = 0.8$. What is the expected frequency of homozygous dominant individuals (DD) under Hardy-Weinberg equilibrium?

Accepted Answer

$p^2 = (0.8)^2 = 0.64$

Question 14

Which of the following is a real-world example of genetic drift?

Accepted Answer

A volcanic eruption randomly kills most of a small lizard population, leaving only a few survivors.

Question 15

Which of the following statements about natural selection is correct?

Accepted Answer

It can lead to adaptation by favoring certain alleles that increase fitness.

Question 16

If a population is not in Hardy-Weinberg equilibrium, what can you conclude?

Accepted Answer

At least one of the Hardy-Weinberg assumptions has been violated.

Question 17

Which of the following best describes the concept of a gene pool?

Accepted Answer

All the alleles present in all individuals of a population.

Question 18

A genetic disease is caused by a recessive allele (r). In a population in Hardy-Weinberg equilibrium, 9% of individuals are affected. What is the frequency of the dominant allele (R)?

Accepted Answer

$q^2 = 0.09 \Rightarrow q = 0.3$, so $p = 1 - 0.3 = 0.7$

Question 19

Which of the following is an example of incomplete dominance?

Accepted Answer

A cross between red and white snapdragons produces pink flowers.

Question 20

Which of the following best explains why gene flow tends to reduce genetic differences between populations?

Accepted Answer

It introduces alleles from one population into another, making their gene pools more similar.

Genetic Variation in Populations: Inheritance, Evolution, and Population Genetics

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