Question 1

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

Accepted Answer

A double helix composed of two polynucleotide strands held together by hydrogen bonds

Question 2

During DNA replication, which enzyme is responsible for adding complementary nucleotides to the template strand?

Accepted Answer

DNA polymerase

Question 3

Which of the following statements about the universality of DNA is correct?

Accepted Answer

DNA's chemical structure is identical in all living organisms

Question 4

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

Accepted Answer

3'-TACGGCAT-5'

Question 5

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

Accepted Answer

DNA is usually double-stranded, while RNA is usually single-stranded

Question 6

A mutation changes a codon from UGG (tryptophan) to UGA. What is the most likely effect on the resulting protein?

Accepted Answer

The protein will be truncated due to a premature stop codon

Question 7

Which process describes the flow of genetic information according to the Central Dogma of molecular biology?

Accepted Answer

DNA → RNA → Protein

Question 8

What is the function of tRNA during translation?

Accepted Answer

It brings amino acids to the ribosome and matches them to the mRNA codon

Question 9

Which of the following best explains why mutations in tumor-suppressor genes can lead to cancer?

Accepted Answer

They result in the loss of inhibition of cell division, allowing uncontrolled growth

Question 10

A scientist wants to amplify a specific DNA segment from a crime scene sample. Which technique should they use?

Accepted Answer

Polymerase chain reaction (PCR)

Question 11

Which of the following is a real-world application of recombinant DNA technology?

Accepted Answer

Producing human insulin in bacteria

Question 12

What is the role of restriction enzymes in genetic engineering?

Accepted Answer

They cut DNA at specific nucleotide sequences

Question 13

Which of the following statements about gene regulation is correct?

Accepted Answer

Gene regulation allows cells to specialize by turning specific genes on or off

Question 14

A point mutation changes a codon from AAA to AAG, both of which code for lysine. What type of mutation is this?

Accepted Answer

Silent mutation

Question 15

Which of the following best describes the function of the CRISPR-Cas9 system in gene editing?

Accepted Answer

It cuts DNA at a targeted location specified by a guide RNA

Question 16

Why is the universality of the genetic code important for genetic engineering?

Accepted Answer

It allows genes from one organism to be expressed in another organism

Question 17

Which of the following is a potential risk associated with genetically modified organisms (GMOs)?

Accepted Answer

Potential unknown hazards to health or the environment

Question 18

What is the main purpose of gel electrophoresis in DNA analysis?

Accepted Answer

To separate DNA fragments by size

Question 19

Which of the following best explains why frameshift mutations often result in nonfunctional proteins?

Accepted Answer

They shift the reading frame, altering many downstream codons

Question 20

In eukaryotic cells, where does transcription occur and what is the immediate product?

Accepted Answer

In the nucleus; pre-mRNA

DNA, RNA, and Genetic Information: Structure, Replication, and Applications

Study Guide - Practice Questions