Question 1

Which of the following best describes the structure of DNA?

Accepted Answer

A double-stranded nucleic acid composed of deoxyribonucleotides

Question 2

Which three components make up a DNA nucleotide?

Accepted Answer

Phosphate group, pentose sugar (deoxyribose), nitrogenous base

Question 3

Which nitrogenous bases are classified as purines in DNA?

Accepted Answer

Adenine and Guanine

Question 4

According to Chargaff’s Rule, which base pairs with cytosine in DNA?

Accepted Answer

Guanine

Question 5

What type of bond connects the sugar and phosphate groups in the DNA backbone?

Accepted Answer

Phosphodiester bond

Question 6

Why are G-C base pairs stronger than A-T base pairs in DNA?

Accepted Answer

G-C pairs have three hydrogen bonds, while A-T pairs have two

Question 7

What does it mean that DNA strands are antiparallel?

Accepted Answer

One strand runs 5' to 3', the other runs 3' to 5'

Question 8

Which scientist’s work was crucial in discovering the double helix structure of DNA, but was not fully credited during her lifetime?

Accepted Answer

Rosalind Franklin

Question 9

What is the function of the promoter region in a gene?

Accepted Answer

It signals where transcription should start

Question 10

During transcription, which direction does RNA polymerase read the DNA template strand?

Accepted Answer

$$3' \rightarrow 5'$$

Question 11

Which base is found in RNA but not in DNA?

Accepted Answer

Uracil

Question 12

What is the role of transcription factors during transcription initiation?

Accepted Answer

They bind RNA polymerase to the promoter

Question 13

Which of the following best explains why DNA must be condensed in the cell nucleus?

Accepted Answer

To fit the long DNA molecule into the small nucleus and regulate gene expression

Question 14

What is the difference between euchromatin and heterochromatin?

Accepted Answer

Euchromatin is unwound and accessible; heterochromatin is tightly wound and inaccessible

Question 15

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

Accepted Answer

3'-TTG ACG TTG GGC-5'

Question 16

Which process is described as 'copying down the recipe' in the central dogma analogy?

Accepted Answer

Transcription

Question 17

What is the direction in which RNA polymerase synthesizes mRNA?

Accepted Answer

$$5' \rightarrow 3'$$

Question 18

Which of the following is a real-world consequence of mutations in promoter regions?

Accepted Answer

Transcription may not start, leading to loss of gene expression

Question 19

Which statement best describes the central dogma of molecular biology?

Accepted Answer

DNA is transcribed into RNA, which is then translated into protein

Question 20

What is the function of the terminator sequence in a gene?

Accepted Answer

It signals where transcription should end

DNA Structure and Gene Transcription: Foundations of Molecular Biology

Study Guide - Practice Questions