Question 1

Which of the following best describes the process by which genetic information is transferred from DNA to protein within a cell?

Accepted Answer

Transcription followed by translation

Question 2

What is the correct chemical structure of a nucleotide in DNA?

Accepted Answer

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

Question 3

Which of the following statements about the double helix structure of DNA is CORRECT?

Accepted Answer

The two strands are antiparallel and held together by hydrogen bonds between bases

Question 4

If a DNA molecule contains 20% adenine, what percentage of guanine does it contain?

Accepted Answer

$$30\%$$

Question 5

Which experiment provided the first strong evidence that DNA is the genetic material?

Accepted Answer

Hershey and Chase experiment

Question 6

What is the role of histone proteins in eukaryotic chromatin?

Accepted Answer

They package DNA into nucleosomes, aiding in compaction and regulation

Question 7

Which of the following modifications to histones can make DNA more accessible for transcription?

Accepted Answer

Acetylation of histones

Question 8

A researcher finds that a DNA sample has a higher melting temperature ($$T_m) $$than expected. Which of the following is the most likely explanation?

Accepted Answer

The DNA has a higher proportion of G-C base pairs

Question 9

Which of the following best describes the difference between heterochromatin and euchromatin?

Accepted Answer

Heterochromatin is tightly packed and transcriptionally inactive; euchromatin is loosely packed and active

Question 10

Which of the following is TRUE about supercoiled DNA in bacterial chromosomes?

Accepted Answer

It is circular and negatively supercoiled

Question 11

What is the function of topoisomerase enzymes in eukaryotic cells?

Accepted Answer

They relieve supercoiling by cutting and rejoining DNA strands

Question 12

Which of the following statements about B-DNA and Z-DNA is correct?

Accepted Answer

B-DNA is right-handed and Z-DNA is left-handed

Question 13

A scientist is studying the hybridization of DNA strands. What is the main reason why hybridization is useful in molecular biology?

Accepted Answer

It enables the detection of specific DNA sequences by complementary base pairing

Question 14

Which of the following best explains why the sugar-phosphate backbone is important in the DNA double helix?

Accepted Answer

It stabilizes the structure and protects the bases from degradation

Question 15

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

Accepted Answer

Helicase

Question 16

Which of the following is a correct abbreviation for the size of a genome?

Accepted Answer

$$Gb ($$gigabase)

Question 17

A mutation causes the loss of function in a histone acetyltransferase enzyme. What is the most likely effect on chromatin structure?

Accepted Answer

Chromatin will become more condensed and transcriptionally inactive

Question 18

Which of the following is TRUE about the packaging of DNA in eukaryotic cells during cell division?

Accepted Answer

Chromatin becomes highly compacted into chromosomes

Question 19

Which of the following is a real-world application of FISH (fluorescence in situ hybridization) in medicine?

Accepted Answer

Detecting specific DNA sequences in chromosomes to diagnose genetic disorders

Question 20

A patient’s cells are found to have a defect in chromatin remodeling enzymes. Which of the following is the most likely consequence?

Accepted Answer

Gene expression is altered due to improper chromatin structure

DNA, Chromosomes, and the Nucleus: Structure, Function, and Organization

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