Question 1

Which of the following best explains how Mendel’s law of independent assortment relates to the behavior of chromosomes during meiosis?

Accepted Answer

Homologous chromosomes separate randomly during meiosis I, leading to the independent assortment of alleles.

Question 2

In Morgan’s experiments with Drosophila, why did white-eyed flies appear only in males in the F2 generation when a red-eyed female was crossed with a white-eyed male?

Accepted Answer

The gene for eye color is located on the X chromosome, and males have only one X chromosome.

Question 3

Which of the following scenarios best illustrates the effect of X inactivation in female mammals?

Accepted Answer

A female cat with heterozygous alleles for fur color displays patches of black and orange fur.

Question 4

If two genes are located close together on the same chromosome, which of the following is most likely to occur?

Accepted Answer

They will be inherited together more often than not due to genetic linkage.

Question 5

A human cell with a karyotype of 47,XXY is an example of which chromosomal alteration?

Accepted Answer

Aneuploidy, specifically trisomy of the sex chromosomes.

Question 6

Which of the following best describes the inheritance of mitochondrial DNA?

Accepted Answer

It is inherited exclusively from the mother, independent of Mendelian patterns.

Question 7

Which experiment provided the strongest evidence that DNA is the genetic material?

Accepted Answer

Hershey and Chase’s experiment using bacteriophages labeled with radioactive phosphorus and sulfur.

Question 8

During DNA replication, which enzyme is responsible for synthesizing short RNA primers?

Accepted Answer

Primase

Question 9

Which of the following statements correctly compares prokaryotic and eukaryotic DNA replication?

Accepted Answer

Prokaryotic DNA replication begins at a single origin, while eukaryotic replication begins at multiple origins.

Question 10

Which level of chromatin packing is most directly associated with gene expression in eukaryotes?

Accepted Answer

Euchromatin, which is less condensed and accessible to transcription machinery.

Question 11

A point mutation changes a codon from $$	ext{UAC} ($$tyrosine) to $$	ext{UAA} ($$stop codon). What type of mutation is this, and what is its likely effect?

Accepted Answer

Nonsense mutation; it results in premature termination of translation.

Question 12

Which of the following best describes the function of the lac operon in E. coli?

Accepted Answer

It enables the bacterium to metabolize lactose only when lactose is present and glucose is absent.

Question 13

Which stage of eukaryotic gene expression is most commonly regulated to control the amount of protein produced?

Accepted Answer

Transcription initiation

Question 14

Which of the following statements about viruses is correct?

Accepted Answer

Viruses can replicate only inside a host cell by using the host’s machinery.

Question 15

Which of the following best describes a prion?

Accepted Answer

A misfolded protein that can induce other proteins to misfold, causing disease.

Question 16

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

Accepted Answer

Natural selection is acting on the population.

Question 17

Which of the following is an example of a postzygotic reproductive barrier?

Accepted Answer

Hybrid offspring are sterile and cannot produce viable gametes.

Question 18

Which process is most likely to result in the rapid formation of new species in a population that becomes geographically isolated?

Accepted Answer

Allopatric speciation

Question 19

A population of beetles has the following genotype frequencies: $$p^2 = 0.36$, 2pq = 0.48$, q^2$ = 0.16. $$What are the allele frequencies of $$p$$ and $$q$$?

Accepted Answer

$$p = 0.6$$, $$q = 0.4$$

Genetics, Gene Expression, Evolution, and Speciation: Study Guide

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