Question 1

Which of the following statements best describes the difference between the coding strand and the template strand during transcription?

Accepted Answer

The template strand is read by RNA polymerase in the 3' to 5' direction to synthesize mRNA in the 5' to 3' direction.

Question 2

A DNA molecule consists of 30% adenine. According to Chargaff's rule, what percentage of guanine would you expect in this DNA?

Accepted Answer

20%

Question 3

Which enzyme is responsible for relieving supercoiling ahead of the replication fork during DNA replication in E. coli?

Accepted Answer

Topoisomerase (specifically DNA gyrase)

Question 4

What is the major difference between Type I and Type II topoisomerases?

Accepted Answer

Type I topoisomerases cut one strand of DNA, while Type II cut both strands.

Question 5

During DNA replication, Okazaki fragments are formed on which strand and why?

Accepted Answer

On the lagging strand because synthesis is discontinuous in the 5' to 3' direction.

Question 6

Which of the following best explains the semiconservative nature of DNA replication?

Accepted Answer

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

Question 7

A mutation changes a codon from UAU to UAC in an mRNA sequence. What effect will this have on the protein product?

Accepted Answer

It will have no effect because both codons code for tyrosine (a silent mutation).

Question 8

Which of the following is NOT a property of the genetic code?

Accepted Answer

It is overlapping, meaning one nucleotide can be part of multiple codons.

Question 9

Which of the following statements about histones is correct?

Accepted Answer

Histones are octameric proteins that help package DNA into nucleosomes.

Question 10

What is the function of the 5' cap added to eukaryotic mRNA?

Accepted Answer

It facilitates ribosome binding and protects mRNA from degradation.

Question 11

Which of the following best describes the role of the anticodon in tRNA?

Accepted Answer

It pairs with the complementary codon on mRNA to ensure correct amino acid incorporation.

Question 12

Which of the following is a characteristic of euchromatin compared to heterochromatin?

Accepted Answer

Euchromatin is less densely packed and more transcriptionally active.

Question 13

Which of the following best describes the phosphodiester bond in DNA?

Accepted Answer

It links the 3' carbon of one nucleotide to the 5' phosphate of the next nucleotide.

Question 14

If a eukaryotic cell has 8 chromosomes at G1 phase, how many DNA molecules will it have at the start of M phase?

Accepted Answer

16

Question 15

Which of the following is true regarding negative supercoiling of DNA?

Accepted Answer

It is found in most prokaryotic chromosomes and facilitates strand separation during replication.

Question 16

Which of the following best describes the central dogma of molecular biology?

Accepted Answer

DNA is replicated, transcribed into RNA, and RNA is translated into protein.

Question 17

Which of the following is NOT a step in the polymerase chain reaction (PCR)?

Accepted Answer

Transcription

Question 18

How many hydrogen bonds are formed between guanine and cytosine in a DNA double helix?

Accepted Answer

Three

Question 19

Which of the following best explains the C-value paradox?

Accepted Answer

Genome size does not correlate with organismal complexity.

Question 20

Which of the following is a function of telomerase?

Accepted Answer

It adds repetitive DNA sequences to the ends of chromosomes to prevent shortening during replication.

Comprehensive Study Guide: Core Concepts in Genetics

Study Guide - Practice Questions