Question 1

During which phase of the cell cycle does DNA replication occur in eukaryotic cells?

Accepted Answer

S phase

Question 2

Which of the following correctly describes the structure of a nucleotide found in DNA?

Accepted Answer

A phosphate group, a deoxyribose sugar, and a nitrogenous base

Question 3

Which base is found in RNA but not in DNA?

Accepted Answer

Uracil

Question 4

If a segment of DNA has the sequence 5'-ATCG-3', what is the complementary sequence on the opposite strand?

Accepted Answer

3'-TAGC-5'

Question 5

Which enzyme is responsible for adding new DNA nucleotides during replication?

Accepted Answer

DNA polymerase

Question 6

What is the role of DNA helicase in DNA replication?

Accepted Answer

It unwinds and separates the DNA strands at the replication fork

Question 7

Which of the following best explains why DNA replication is described as 'semi-conservative'?

Accepted Answer

Each new DNA molecule contains one original strand and one new strand

Question 8

A mutation occurs when an incorrect base is paired during DNA replication. Which of the following is a possible consequence if this mutation is not repaired?

Accepted Answer

The mutation may result in cell death, cancer, or have no effect

Question 9

Which of the following is NOT a component of a DNA nucleotide?

Accepted Answer

Carboxyl group

Question 10

In humans, how many chromosomes are present in a typical somatic cell?

Accepted Answer

46

Question 11

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

Accepted Answer

Adenine pairs with Thymine

Question 12

What is the function of DNA ligase during DNA replication?

Accepted Answer

It joins Okazaki fragments to form a continuous DNA strand

Question 13

Which process involves the synthesis of a working copy of DNA in the form of mRNA?

Accepted Answer

Transcription

Question 14

A scientist discovers a mutation in a gene that codes for a DNA repair enzyme. What is the most likely consequence for the cell?

Accepted Answer

The cell may accumulate more mutations, increasing the risk of cancer

Question 15

Which of the following best describes the role of RNA primers in DNA replication?

Accepted Answer

They mark the starting point for DNA synthesis

Question 16

If a DNA molecule contains 30% adenine, what percentage of thymine does it contain?

Accepted Answer

$30\%$

Question 17

Which of the following statements about mutations is TRUE?

Accepted Answer

Mutations can be neutral, harmful, or beneficial

Question 18

During DNA replication, which direction does DNA polymerase add new nucleotides?

Accepted Answer

5' to 3' direction

Question 19

A patient is exposed to X-rays, which are known to cause mutations. What is the most likely effect on their DNA?

Accepted Answer

Physical forces like X-rays can cause alterations in the DNA code

Question 20

Which of the following best describes a gene?

Accepted Answer

A segment of DNA that codes for a specific protein

DNA Replication and Nucleic Acids: Structure, Function, and Cellular Role

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