Question 1

Which of the following best describes the structure of DNA as discovered by Watson and Crick?

Accepted Answer

DNA is a double-stranded helix with antiparallel strands.

Question 2

In the process of DNA replication, which enzyme is responsible for unwinding the double helix?

Accepted Answer

DNA Helicase

Question 3

Which of the following base pairs is stabilized by three hydrogen bonds, contributing more to the stability of the DNA double helix?

Accepted Answer

Cytosine-Guanine

Question 4

What is the direction of DNA synthesis during replication?

Accepted Answer

5' to 3'

Question 5

Which enzyme joins Okazaki fragments together on the lagging strand during DNA replication?

Accepted Answer

DNA Ligase

Question 6

The Central Dogma Theory states that genetic information flows from DNA to RNA to protein. Which process describes the synthesis of RNA from DNA?

Accepted Answer

Transcription

Question 7

Which of the following is NOT a function of bacteria in our daily lives?

Accepted Answer

Causing all diseases

Question 8

In Griffith's experiment, what was the outcome when mice were injected with a mixture of living R strain and heat-killed S strain bacteria?

Accepted Answer

Mouse dies

Question 9

Which of the following statements about the sugar-phosphate backbone of DNA is correct?

Accepted Answer

It is formed by phosphodiester bonds between nucleotides.

Question 10

Which enzyme removes the RNA primer from Okazaki fragments during DNA replication?

Accepted Answer

RNAase H

Question 11

A microorganism is defined as:

Accepted Answer

A microscopic organism, which may exist as a single cell or a colony.

Question 12

Which of the following is a purine base found in DNA?

Accepted Answer

Adenine

Question 13

DNA replication is described as semi-conservative. What does this mean?

Accepted Answer

Each new DNA molecule contains one old strand and one new strand.

Question 14

Which of the following is a real-life example of microorganisms present in our daily environment?

Accepted Answer

Microorganisms are present in the air, water, food, skin, and inside our bodies.

Question 15

Which of the following statements about the antiparallel nature of DNA strands is correct?

Accepted Answer

One strand runs 5' to 3', while the other runs 3' to 5'.

Question 16

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

Accepted Answer

DNA Primase

Question 17

What is the role of topoisomerase (gyrase) in DNA replication?

Accepted Answer

It introduces supercoils to help pack DNA into a small volume.

Question 18

Which of the following is a correct formula for the phosphodiester bond formation in DNA?

Accepted Answer

Phosphate group links the 5' carbon of one nucleotide to the 3' hydroxyl of another: $$	ext{5'}	ext{-}PO_4$	ext{-}3'	ext{-}OH$$

Question 19

During DNA replication, why is synthesis on the lagging strand discontinuous?

Accepted Answer

The lagging strand is synthesized in short fragments (Okazaki fragments) because it is antiparallel to the leading strand.

Question 20

Which of the following best explains the outcome of mixing living R strain and heat-killed S strain in Griffith's experiment?

Accepted Answer

The R strain becomes virulent due to transformation.

Foundations of Microbiology and Microbial Genetics

Study Guide - Practice Questions