Question 1

Which of the following best describes the structure of DNA?

Accepted Answer

A double helix with sugar-phosphate backbones and nitrogen bases paired in the middle

Question 2

During DNA replication, which enzyme is primarily responsible for adding new nucleotides to the growing DNA strand?

Accepted Answer

DNA polymerase

Question 3

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

Accepted Answer

3'-TAGC-5'

Question 4

Which of the following statements about the difference between DNA and RNA is correct?

Accepted Answer

DNA contains deoxyribose sugar, while RNA contains ribose sugar

Question 5

What is the significance of semi-conservative replication in DNA?

Accepted Answer

Each new DNA molecule contains one old and one new strand

Question 6

A mutation occurs in the DNA of a germ cell that becomes a sperm cell. What is a possible consequence?

Accepted Answer

The mutation can be passed on to offspring

Question 7

Which of the following best explains why hydrogen bonds are important in the structure of DNA?

Accepted Answer

They allow the two DNA strands to separate easily during replication

Question 8

If a DNA molecule is composed of 30% adenine, what percentage of thymine would you expect to find?

Accepted Answer

$$30\%$$

Question 9

Which of the following is a correct pairing of nitrogenous bases in DNA?

Accepted Answer

Adenine and Thymine

Question 10

A scientist is studying a segment of DNA and finds a mutation in a single gene. Which of the following is a likely outcome?

Accepted Answer

Only the protein coded by that gene may be affected

Question 11

Which of the following best describes a gene?

Accepted Answer

A section of DNA that codes for a protein

Question 12

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

Accepted Answer

S phase

Question 13

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

Accepted Answer

Amino acid

Question 14

If a mistake occurs during DNA replication in a body cell, such as a skin cell, what is the most likely result?

Accepted Answer

The mutation will only affect the individual

Question 15

Which of the following best explains why DNA replication is necessary before cell division?

Accepted Answer

To ensure each new cell has an identical copy of the DNA

Question 16

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

Accepted Answer

It is formed by strong covalent bonds

Question 17

Which of the following scenarios would most likely result in a genetic disorder passed to offspring?

Accepted Answer

A mutation in the DNA of a sperm cell

Question 18

Which of the following is a difference between DNA and RNA?

Accepted Answer

DNA is double-stranded, RNA is single-stranded

Question 19

If a DNA strand has the sequence 5'-CGTACG-3', what would be the sequence of the complementary RNA strand?

Accepted Answer

3'-GCAUGC-5'

Question 20

Which of the following best describes the role of genes in cells?

Accepted Answer

Genes provide instructions for making proteins

DNA Structure and Replication: Study Notes

Study Guide - Practice Questions