Question 1

Which of the following best describes the Central Dogma of molecular genetics?

Accepted Answer

DNA is transcribed into RNA, which is then translated into protein.

Question 2

A plant species is found to have three complete sets of chromosomes from the same species. What is the term for this condition?

Accepted Answer

Autopolyploidy

Question 3

Which of the following statements about the genetic code is correct?

Accepted Answer

The genetic code is unambiguous but degenerate.

Question 4

A patient is diagnosed with Turner syndrome. Which of the following karyotypes would you expect to find?

Accepted Answer

$$45, X$$

Question 5

Which enzyme is responsible for synthesizing the RNA primer during DNA replication?

Accepted Answer

Primase

Question 6

A deletion of a large region on one chromosome often results in lethality when homozygous. Why?

Accepted Answer

Essential genes are lost, and both copies are required for viability.

Question 7

Which of the following best explains why telomerase is essential for the maintenance of chromosomes in eukaryotic cells?

Accepted Answer

It extends the 3' ends of chromosomes, preventing loss of genetic material during replication.

Question 8

A cross between two heterozygous individuals for two genes (AaBb x AaBb) produces the following offspring: 9 with both dominant traits, 3 with one dominant and one recessive trait, 3 with the other dominant and recessive trait, and 1 with both recessive traits. What does this ratio suggest about the genes?

Accepted Answer

The genes assort independently.

Question 9

Which of the following is a function of the TATA box in eukaryotic transcription?

Accepted Answer

It serves as a binding site for transcription factors and RNA polymerase II.

Question 10

A scientist is using a three-point test cross to map genes A, B, and C. The recombination frequencies are: A-B = 10%, B-C = 20%, and A-C = 28%. What is the most likely order of the genes?

Accepted Answer

A - B - C

Question 11

Which of the following best describes the function of single-stranded binding proteins (SSBs) during DNA replication?

Accepted Answer

They stabilize unwound DNA strands and prevent them from reannealing.

Question 12

Which chromosomal rearrangement is associated with the Philadelphia chromosome and chronic myelogenous leukemia (CML)?

Accepted Answer

Reciprocal translocation between chromosomes 9 and 22

Question 13

Which of the following best explains why the Hershey-Chase experiment was important in molecular genetics?

Accepted Answer

It demonstrated that DNA, not protein, is the genetic material in phages.

Question 14

Which of the following is a key difference between euchromatin and heterochromatin?

Accepted Answer

Euchromatin is less condensed and transcriptionally active, while heterochromatin is more condensed and transcriptionally inactive.

Question 15

A mutation causes a single nucleotide change that results in a premature stop codon. What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 16

Which of the following best describes the function of DNA ligase during DNA replication?

Accepted Answer

It joins Okazaki fragments on the lagging strand by forming phosphodiester bonds.

Question 17

Which of the following is a consequence of nondisjunction during meiosis?

Accepted Answer

Aneuploidy, such as trisomy 21 (Down syndrome)

Question 18

Which of the following best explains the role of topoisomerase during DNA replication?

Accepted Answer

It relieves supercoiling ahead of the replication fork by cutting and rejoining DNA strands.

Question 19

Which of the following statements about the semiconservative model of DNA replication is correct?

Accepted Answer

Each daughter DNA molecule consists of one parental strand and one newly synthesized strand.

Question 20

A researcher is studying a gene with the following sequence: 5'-ATG GAA TGA-3'. What is the function of the codon 'TGA' in this sequence?

Accepted Answer

It is a stop codon, signaling termination of translation.

Genetics Study Guide: Chromosomal Mutations, DNA Structure, Replication, and Gene Expression

Study Guide - Practice Questions

Study Guide - Flashcards