Question 1

Which of the following best describes the structure of a DNA nucleotide?

Accepted Answer

A phosphate group, a deoxyribose sugar, and a nitrogen-containing base

Question 2

Chargaff’s rule states that in DNA, the amount of adenine is equal to the amount of thymine, and the amount of guanine is equal to the amount of cytosine. If a DNA sample contains 30% adenine, what percentage of guanine would you expect?

Accepted Answer

20%

Question 3

Which scientists used X-ray diffraction to help determine the structure of DNA?

Accepted Answer

Maurice Wilkins and Rosalind Franklin

Question 4

What is the significance of complementary base pairing in DNA replication?

Accepted Answer

It ensures that each new DNA strand is identical to the original

Question 5

During DNA replication, which enzyme is responsible for unwinding the double helix?

Accepted Answer

DNA helicase

Question 6

DNA replication is described as semiconservative. What does this mean?

Accepted Answer

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

Question 7

A mutation that changes a single nucleotide pair in DNA is called:

Accepted Answer

Point mutation

Question 8

Which of the following best explains why DNA can encode a vast amount of genetic information despite having only four types of nucleotides?

Accepted Answer

The sequence of nucleotides can be arranged in many different ways

Question 9

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

Accepted Answer

3'-TAGC-5'

Question 10

Which of the following is NOT a possible result of a mutation?

Accepted Answer

Formation of a double helix

Question 11

DNA repair enzymes play a critical role in maintaining genetic constancy. What is their primary function?

Accepted Answer

They proofread and fix mistakes in newly synthesized DNA

Question 12

Which of the following best describes the antiparallel nature of DNA strands?

Accepted Answer

The strands run in opposite directions, with one having a free sugar and the other a free phosphate at each end

Question 13

A scientist exposes cells to a chemical that causes frequent insertion mutations. Which of the following is most likely to occur?

Accepted Answer

The DNA sequence will gain extra nucleotide pairs

Question 14

Which of the following equations correctly represents the relationship between the four bases in DNA according to Chargaff’s rule?

Accepted Answer

$$A = T$$ and $$G = C$$

Question 15

Which of the following scenarios best illustrates a real-world consequence of a point mutation?

Accepted Answer

A person develops sickle cell anemia due to a single nucleotide change in the hemoglobin gene

Question 16

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

Accepted Answer

DNA polymerase

Question 17

A deletion mutation occurs in a gene. What is the most likely effect on the protein encoded by that gene?

Accepted Answer

The protein may be shorter or nonfunctional

Question 18

Which of the following best describes the role of hydrogen bonds in the DNA double helix?

Accepted Answer

They hold the complementary nitrogen-containing bases together

Question 19

Translocation mutations involve:

Accepted Answer

The movement of large pieces of chromosomes to new locations

Question 20

Which of the following is a direct consequence of the sequence of nucleotides in DNA?

Accepted Answer

The sequence determines the genetic information encoded in DNA

DNA: The Molecule of Heredity – Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards