$$\text{Adenine-Thymine: 2; Guanine-Cytosine: 3}$$

$$5'\text{ – UCGCAU – }3'$$

Question 1

Which of the following best describes the antiparallel nature of the DNA double helix?

Accepted Answer

The two strands run in opposite directions: one strand runs 5’ to 3’, and the other runs 3’ to 5’.

Question 2

In the structure of DNA, where are the hydrophobic nitrogenous bases and the hydrophilic phosphate groups located?

Accepted Answer

The nitrogenous bases are in the interior of the helix, while the phosphate groups are on the exterior.

Question 3

How many hydrogen bonds form between adenine and thymine, and between guanine and cytosine, respectively?

Accepted Answer

$$	ext{Adenine-Thymine: 2; Guanine-Cytosine: 3}$$

Question 4

Which of the following is NOT a difference between DNA and RNA?

Accepted Answer

DNA can function as a ribozyme, while RNA cannot.

Question 5

Which type of RNA carries amino acids to the ribosome during translation?

Accepted Answer

Transfer RNA (tRNA)

Question 6

During DNA replication, which enzyme is responsible for unwinding the DNA double helix at the replication fork?

Accepted Answer

Helicase

Question 7

What does it mean that DNA replication is semiconservative?

Accepted Answer

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

Question 8

A DNA template strand has the sequence 3’ – AGCGTA – 5’. What is the corresponding mRNA sequence?

Accepted Answer

$$5'	ext{ – UCGCAU – }3'$$

Question 9

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

Accepted Answer

It synthesizes new DNA strands by adding nucleotides to a pre-existing primer.

Question 10

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

Accepted Answer

It is redundant, meaning that multiple codons can code for the same amino acid.

Question 11

What is the function of the start codon in translation, and which amino acid does it code for?

Accepted Answer

It signals the beginning of translation and codes for methionine.

Question 12

Which of the following best describes a missense mutation?

Accepted Answer

A point mutation that results in a codon coding for a different amino acid.

Question 13

A frameshift mutation can be caused by which of the following events?

Accepted Answer

Insertion or deletion of nucleotides not in multiples of three.

Question 14

Which process involves the uptake of naked DNA from the environment by a bacterial cell?

Accepted Answer

Transformation

Question 15

During bacterial conjugation, what is transferred from one cell to another?

Accepted Answer

A plasmid or a portion of chromosomal DNA

Question 16

Which of the following best explains why horizontal gene transfer is beneficial to bacteria?

Accepted Answer

It increases genetic diversity, allowing bacteria to adapt to new environments.

Question 17

Which enzyme relieves supercoiling ahead of the replication fork during DNA replication?

Accepted Answer

Topoisomerase

Question 18

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

Accepted Answer

Nonsense mutation; it introduces a premature stop codon.

Question 19

Which of the following best describes the role of the anticodon on tRNA during translation?

Accepted Answer

It base-pairs with the complementary codon on mRNA to ensure the correct amino acid is added.

Question 20

In the process of transduction, how is genetic material transferred between bacteria?

Accepted Answer

By a bacteriophage (virus) transferring DNA from one bacterium to another.

Microbiology Chapter 8 Study Guide: Nucleic Acids, DNA Replication, Gene Expression, Mutations, and Horizontal Gene Transfer

Study Guide - Practice Questions