Q: What is the function of a primer during DNA replication?

It provides a free $3'\text{-}OH$ group for DNA polymerase to begin synthesis.

Question 1

Which of the following correctly lists the steps of the central dogma of molecular biology in order?

Accepted Answer

Replication → Transcription → Translation

Question 2

During DNA replication, in which direction does DNA polymerase synthesize the new DNA strand?

Accepted Answer

From $5' \rightarrow 3'$

Question 3

Which of the following statements about DNA base pairing is correct?

Accepted Answer

Adenine pairs with Thymine, and Guanine pairs with Cytosine

Question 4

Which base pair is stronger due to the number of hydrogen bonds formed?

Accepted Answer

Guanine–Cytosine (G–C) pairs

Question 5

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

Accepted Answer

Adenine

Question 6

What is the function of a primer during DNA replication?

Accepted Answer

It provides a free $3'	ext{-}OH$ group for DNA polymerase to begin synthesis.

Question 7

Which end of a DNA strand has a free phosphate group?

Accepted Answer

$5'$ end

Question 8

A mutation causes a DNA polymerase to lose its proofreading ability. What is the most likely consequence?

Accepted Answer

Increased rate of mutations due to uncorrected errors

Question 9

During DNA replication, which strand is synthesized discontinuously, and what are the resulting fragments called?

Accepted Answer

Lagging strand; Okazaki fragments

Question 10

In bacteria, what is the role of the promoter sequence in gene expression?

Accepted Answer

It signals the beginning of a gene and initiates transcription.

Question 11

Which consensus sequences are commonly found in bacterial promoters and recognized by RNA polymerase?

Accepted Answer

$-10$ and $-35$

Question 12

A scientist is designing an experiment to increase the transcription of a bacterial gene. Which modification would most likely enhance promoter recognition by RNA polymerase?

Accepted Answer

Making the promoter sequence more similar to the $-10$ and $-35$ consensus sequences

Question 13

Which of the following best describes the difference between the leading and lagging strands during DNA replication?

Accepted Answer

The leading strand is synthesized continuously, while the lagging strand is synthesized discontinuously.

Question 14

Which of the following statements about the $3'$ and $5'$ ends of DNA is correct?

Accepted Answer

The $3'$ end has a free $-OH$ group, and the $5'$ end has a phosphate group.

Question 15

If a DNA sequence has a high proportion of G–C base pairs, what property will it most likely exhibit compared to a sequence with more A–T base pairs?

Accepted Answer

Higher melting temperature due to stronger hydrogen bonding

Question 16

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

Accepted Answer

Thymine

Question 17

A researcher is studying a bacterial gene with a mutated promoter that is very different from the consensus $-10$ and $-35$ sequences. What is the most likely effect on gene expression?

Accepted Answer

Transcription of the gene will be reduced or absent.

Question 18

Which of the following best explains why DNA polymerase cannot initiate synthesis of a new DNA strand on its own?

Accepted Answer

It requires a primer with a free $3'	ext{-}OH$ group to add nucleotides.

Question 19

During DNA replication, what would happen if the primer was not removed and replaced with DNA?

Accepted Answer

The resulting DNA would contain RNA segments, potentially leading to instability or errors.

Question 20

Which of the following is true regarding the directionality of DNA and RNA synthesis?

Accepted Answer

Both DNA and RNA are synthesized in the $5' \rightarrow 3'$ direction.

Fundamentals of DNA Structure and Function: Replication, Transcription, and Translation

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