DNA Structure and Function: Interactive Learning Quizzes for Medical Students

Question 1

Which of the following base pairs is not found in the standard B-form DNA?

Accepted Answer

U-G

Answer

A-T

Answer

C-G

Answer

G-C

Question 2

What is the primary function of the hydrogen bonds in DNA?

Accepted Answer

To maintain the double helix structure

Answer

To allow for DNA replication and transcription

Answer

To prevent DNA unwinding

Answer

To regulate gene expression

Question 3

Which components make up the sugar-phosphate backbone of DNA?

Accepted Answer

Deoxyribose and phosphate

Answer

Ribose and phosphate

Answer

Adenine and thymine

Answer

Guanine and cytosine

Question 4

What is a consequence of DNA denaturation?

Accepted Answer

Loss of base pairing

Answer

Increased viscosity

Answer

Increased absorbance at 260 nm

Answer

Enhanced stability

Question 5

Which of the following describes the primary role of topoisomerases in relation to DNA structure and function?

Accepted Answer

Regulate DNA supercoiling

Answer

Repair damaged DNA strands

Answer

Initiate DNA replication

Answer

Terminate DNA transcription

Question 6

Which of the following is an example of a modified nucleotide found in DNA?

Accepted Answer

5-methylcytosine

Answer

Inosine

Answer

Pseudouridine

Answer

Dihydrouridine

Question 7

What is the main significance of DNA methylation?

Accepted Answer

Gene regulation

Answer

DNA repair

Answer

Protein synthesis

Answer

Cell cycle control

Question 8

Which technique is primarily used to determine the sequence of nucleotides in DNA?

Accepted Answer

DNA sequencing

Answer

Gel electrophoresis

Answer

Polymerase chain reaction

Answer

Microarray analysis

Question 9

What is the process during which DNA is duplicated prior to cell division?

Accepted Answer

Replication

Answer

Transcription

Answer

Translation

Answer

Mutation

Question 10

What is the term used to describe a specific sequence of nucleotides that carries genetic information and codes for a specific protein?

Accepted Answer

Gene

Answer

Genome

Answer

Promoter

Answer

Enhancer

Question 11

Which of the following is NOT a nitrogenous base found in DNA?

Accepted Answer

Uracil

Answer

Adenine

Answer

Thymine

Answer

Guanine

Question 12

Describe the structure of the DNA double helix accurately.

Accepted Answer

Double-stranded with hydrogen bonds between base pairs

Answer

Single-stranded with complementary nucleotides

Answer

Triple-stranded with base pairs stacked on top of each other

Answer

Coiled with base pairs arranged linearly

Question 13

What is the primary function of DNA in living organisms?

Accepted Answer

Storing genetic information

Answer

Regulating gene expression

Answer

Providing energy for cellular processes

Answer

Synthesizing proteins

Question 14

Identify the groove in DNA formed by the hydrophilic deoxyribose-phosphate backbone.

Accepted Answer

Minor groove

Answer

Major groove

Answer

Helix groove

Answer

Base groove

Question 15

Which specific hydrogen bonding pattern occurs between adenine and thymine in DNA?

Accepted Answer

Double hydrogen bond

Answer

Single hydrogen bond

Answer

Triple hydrogen bond

Answer

No hydrogen bonding

Question 16

Which type of chemical bond connects the deoxyribose sugars in the DNA backbone?

Accepted Answer

Phosphodiester bonds

Answer

Glycosidic bonds

Answer

Peptide bonds

Answer

Hydrogen bonds

Question 17

Which of the following best describes the structure of DNA?

Accepted Answer

A double helix with antiparallel strands held together by base pairing.

Answer

A double helix with parallel strands held together by covalent bonding.

Answer

A single helix with parallel strands held together by hydrogen bonding.

Answer

A single helix with antiparallel strands held together by ionic bonding.

Question 18

What is the complementary base pair for guanine (G) in DNA?

Accepted Answer

Cytosine (C)

Answer

Adenine (A)

Answer

Uracil (U)

Answer

Thymine (T)

Question 19

Which of the following statements is TRUE about the minor groove of DNA?

Accepted Answer

It is narrower than the major groove.

Answer

It contains more hydrogen bonds than the major groove.

Answer

It binds proteins involved in gene regulation more frequently than the major groove.

Answer

It is recognized by a wider range of DNA-binding proteins compared to the major groove.

Question 20

What is the primary function of the sugar-phosphate backbone in DNA?

Accepted Answer

Provides structural support and allows for chemical modifications.

Answer

Binds proteins involved in DNA replication.

Answer

Encodes genetic information.

Question 21

Which of the following is a key role of DNA methylation?

Accepted Answer

Regulating gene expression.

Answer

Enhancing DNA repair.

Answer

Promoting DNA replication.

Answer

Stabilizing DNA structure.

Question 22

Which enzyme is responsible for unwinding and separating the two strands of DNA during replication?

Accepted Answer

Helicase

Answer

Topoisomerase

Answer

DNA polymerase

Answer

DNA ligase

Question 23

What is the primary function of telomeres in DNA?

Accepted Answer

To protect chromosome ends from degradation and prevent loss of genetic information.

Answer

To bind proteins involved in DNA repair.

Answer

To regulate gene expression.

Answer

To enhance DNA replication efficiency.

Question 24

Which of the following is a genetic disorder caused by mutations in DNA repair genes, resulting in increased sensitivity to UV radiation?

Accepted Answer

Xeroderma pigmentosum

Answer

Cystic fibrosis

Answer

Down syndrome

Answer

Sickle cell anemia

Question 25

What is the main significance of supercoiling in DNA?

Accepted Answer

It facilitates DNA packaging within the nucleus and can regulate gene expression.

Answer

It promotes DNA replication by increasing accessibility to the replication machinery.

Answer

It stabilizes DNA structure by reducing torsional stress.

Answer

It enhances DNA repair by facilitating the recruitment of repair enzymes.