Question 1

Which of the following best describes the difference between a nucleotide and a nucleoside?

Accepted Answer

A nucleoside contains a nitrogenous base and a pentose sugar, while a nucleotide contains a nitrogenous base, a pentose sugar, and a phosphate group.

Question 2

Which type of bond holds complementary base pairs together in the DNA double helix?

Accepted Answer

Hydrogen bonds

Question 3

A DNA strand has the sequence 5'-ATGCCGTA-3'. What is the complementary sequence, including correct directionality?

Accepted Answer

3'-TACGGCAT-5'

Question 4

Which of the following statements about DNA replication in bacteria is correct?

Accepted Answer

Bacterial chromosomes have a single origin of replication.

Question 5

During DNA replication, which enzyme synthesizes short RNA primers on the lagging strand?

Accepted Answer

Primase

Question 6

What is the main difference between leading strand and lagging strand synthesis during DNA replication?

Accepted Answer

The leading strand is synthesized continuously, while the lagging strand is synthesized discontinuously.

Question 7

Which of the following best explains the function of DNA ligase during replication?

Accepted Answer

It joins Okazaki fragments by forming phosphodiester bonds between them.

Question 8

In eukaryotic transcription, what is the role of the TATA box?

Accepted Answer

It serves as a core promoter element, helping to position RNA polymerase II for transcription initiation.

Question 9

Which process is responsible for removing introns from pre-mRNA in eukaryotes?

Accepted Answer

Splicing

Question 10

What is the function of the Shine-Dalgarno sequence in prokaryotic translation?

Accepted Answer

It serves as a ribosome binding site to initiate translation.

Question 11

Which of the following best describes the semiconservative model of DNA replication?

Accepted Answer

Each daughter DNA molecule consists of one parental strand and one newly synthesized strand.

Question 12

Which enzyme is responsible for unwinding the DNA double helix during replication?

Accepted Answer

Helicase

Question 13

A mutation in the gene encoding telomerase would most likely affect which cellular process?

Accepted Answer

Maintenance of chromosome ends during replication

Question 14

Which of the following is a function of the poly-A tail added to eukaryotic mRNA?

Accepted Answer

It protects mRNA from degradation and assists in export from the nucleus.

Question 15

Which of the following statements about alternative splicing is correct?

Accepted Answer

It allows a single gene to produce multiple protein isoforms.

Question 16

If a ribosome reads an mRNA sequence 5'-AUGGCUUAA-3', what is the corresponding amino acid sequence? (Use the standard genetic code: AUG = Met, GCU = Ala, UAA = Stop)

Accepted Answer

Met-Ala-Stop

Question 17

Which of the following best describes the directionality of DNA polymerase during replication?

Accepted Answer

It synthesizes DNA in the 5' to 3' direction.

Question 18

Which of the following is a real-world consequence of defects in DNA polymerase proofreading activity?

Accepted Answer

Increased rates of genetic mutations leading to cancer

Question 19

Which of the following statements about ribozymes is correct?

Accepted Answer

Ribozymes are RNA molecules that act as biological catalysts.

Question 20

Given a double-stranded DNA molecule, how many template strands are used for transcription of a single gene?

Accepted Answer

Only one strand serves as the template for a given gene.

Study Guide: Molecular Structure, Replication, Transcription, and Translation of DNA and RNA

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