Question 1

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

Accepted Answer

Information flows from DNA to RNA to protein.

Question 2

Which statement best explains what is meant by 'DNA carries the instructions to make an organism'?

Accepted Answer

DNA encodes the genetic information that determines the structure and function of proteins.

Question 3

When sketching a DNA double helix, which of the following is correct regarding the orientation of the strands?

Accepted Answer

One strand runs 5' to 3' and the other runs 3' to 5'.

Question 4

Which base pairing is correct according to the rules of DNA structure?

Accepted Answer

Adenine pairs with thymine, and guanine pairs with cytosine.

Question 5

DNA polymerase requires which of the following to begin DNA synthesis?

Accepted Answer

A template strand and a primer with a free 3' hydroxyl group.

Question 6

During DNA replication, what is the immediate effect if DNA polymerase incorporates an incorrect base pair?

Accepted Answer

DNA polymerase can recognize and remove the incorrect base via its 3' to 5' exonuclease activity.

Question 7

Which enzyme is responsible for unwinding the DNA double helix during replication?

Accepted Answer

Helicase

Question 8

What is the primary function of DNA ligase during DNA replication?

Accepted Answer

Joining Okazaki fragments on the lagging strand.

Question 9

Which of the following best distinguishes DNA polymerase from RNA polymerase?

Accepted Answer

DNA polymerase requires a primer, while RNA polymerase does not.

Question 10

During DNA replication, which strand is synthesized continuously, and which is synthesized in fragments?

Accepted Answer

The leading strand is synthesized continuously; the lagging strand is synthesized in fragments.

Question 11

A mutation in the gene encoding DNA gyrase would most likely result in which of the following problems during DNA replication?

Accepted Answer

Accumulation of supercoils ahead of the replication fork.

Question 12

Which of the following best describes the role of sigma factors in bacterial transcription?

Accepted Answer

They help RNA polymerase recognize promoter regions.

Question 13

Which of the following is a key difference between prokaryotic and eukaryotic DNA replication?

Accepted Answer

Eukaryotes have multiple origins of replication, while prokaryotes typically have a single origin.

Question 14

A scientist uses a mutagen to introduce random mutations in a bacterial genome. Which of the following best describes how this could affect transcription?

Accepted Answer

Mutations in promoter regions could prevent RNA polymerase from initiating transcription.

Question 15

Which of the following equations correctly represents the directionality of DNA synthesis?

Accepted Answer

$$5' \rightarrow 3'$$

Question 16

In a scenario where a bacterium uses alternative sigma factors, what is the most likely outcome?

Accepted Answer

The bacterium can regulate different sets of genes in response to environmental changes.

Question 17

Which of the following best explains why some promoters are recognized by RNA polymerase better than others?

Accepted Answer

The sequence of the promoter affects the binding affinity of RNA polymerase.

Question 18

During transcription, which of the following is true regarding the template and coding strands?

Accepted Answer

The template strand is used by RNA polymerase to synthesize a complementary RNA molecule.

Question 19

Which of the following best describes the process by which a bacterial cell converts a gene into a functional protein?

Accepted Answer

Transcription followed by translation.

Question 20

A mutation in the gene encoding primase would most directly affect which step of DNA replication?

Accepted Answer

Synthesis of RNA primers required for DNA polymerase to initiate synthesis.

DNA Structure, Replication, and Transcription: Key Concepts and Enzymes

Study Guide - Practice Questions

Study Guide - Flashcards