Question 1

Which of the following best describes the 'central dogma' of molecular biology?

Accepted Answer

Information flows from DNA to RNA to protein.

Question 2

In eukaryotic cells, what is the correct sequence of events for gene expression?

Accepted Answer

Transcription → RNA processing → Translation

Question 3

During transcription, which DNA strand is used as the template for mRNA synthesis?

Accepted Answer

The template strand (antisense strand)

Question 4

If the DNA template strand has the sequence $$5'	ext{TGCATG}\ 3'$$, what will be the sequence of the mRNA transcript?

Accepted Answer

$$3'	ext{ACGUAC}\ 5'$$

Question 5

Which of the following statements about the genetic code is TRUE?

Accepted Answer

The genetic code is redundant, but not ambiguous.

Question 6

What is the function of the 5' cap and poly-A tail added to eukaryotic mRNA?

Accepted Answer

They protect mRNA from degradation and help export it from the nucleus.

Question 7

A mutation changes a codon from $$	ext{UAC} ($$tyrosine) to $$	ext{UAA} ($$stop). What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 8

Which of the following best explains why insertions and deletions often have more severe effects than substitutions?

Accepted Answer

They can cause frameshift mutations, altering the reading frame.

Question 9

In prokaryotic cells, where does translation occur?

Accepted Answer

In the cytoplasm

Question 10

Which enzyme is responsible for joining an amino acid to its specific tRNA?

Accepted Answer

Aminoacyl-tRNA synthetase

Question 11

A polypeptide is synthesized from the mRNA sequence $$5'	ext{AUG UUU GGC UAA}\ 3'. $$What is the sequence of amino acids produced?

Accepted Answer

Met-Phe-Gly-Stop

Question 12

Which of the following is a function of non-coding RNAs (ncRNAs)?

Accepted Answer

They catalyze peptide bond formation in ribosomes.

Question 13

What is the effect of a frameshift mutation caused by a single nucleotide insertion?

Accepted Answer

It shifts the reading frame, potentially altering all downstream amino acids.

Question 14

Which site on the ribosome holds the tRNA carrying the growing polypeptide chain?

Accepted Answer

P site

Question 15

Alternative RNA splicing allows a single gene to:

Accepted Answer

Produce multiple types of proteins.

Question 16

Which of the following is TRUE about the directionality of transcription?

Accepted Answer

RNA polymerase synthesizes RNA in the 5' to 3' direction.

Question 17

What is the role of transcription factors in eukaryotic transcription?

Accepted Answer

They bind to DNA near genes to promote or inhibit transcription.

Question 18

Which of the following best describes the process of exon shuffling?

Accepted Answer

Chromosomal duplications and translocations move exons to new places, creating new proteins.

Question 19

A mutation in the DNA coding strand changes the sequence $$5'	ext{TTC}\ 3' to$$ $$5'	ext{TTA}\ 3'. $$What is the effect on the mRNA and protein?

Accepted Answer

The mRNA codon changes from $$	ext{AAG} to$$ $$	ext{UUA}$$, resulting in a missense mutation.

Question 20

Which of the following is a real-world application of CRISPR-Cas9 gene editing?

Accepted Answer

It is used to precisely edit and repair DNA sequences in organisms.

Gene Expression: From Gene to Protein (Transcription and Translation)

Study Guide - Practice Questions