Gene Expression: A Comprehensive Guide for Biology Students

Question 1

In the initiation of transcription, what is the main function of sigma factors?

Accepted Answer

Binding to the promoter region and recruiting RNA polymerase for transcription initiation

Answer

Catalyzing the elongation of the RNA molecule during transcription

Answer

Binding to the ribosome and assisting in the translation of mRNA into proteins

Answer

Serving as the template for the synthesis of new RNA molecules during transcription

Question 2

Which event signals the end of translation and the release of the newly formed polypeptide chain?

Accepted Answer

Recognition of a stop codon by a release factor

Answer

Spontaneous breakdown of the ribosome

Answer

Return of tRNA to the available pool

Answer

Degradation of mRNA

Question 3

In eukaryotes, which enzyme initiates transcription?

Accepted Answer

RNA polymerase II

Answer

Helicase

Answer

DNA polymerase

Answer

Primase

Question 4

What is the primary function of tRNA in protein synthesis?

Accepted Answer

Transporting amino acids to the ribosomes

Answer

Forming peptide bonds between amino acids

Answer

Unwinding the DNA double helix

Answer

Proofreading the mRNA sequence

Question 5

Which of the following is not a type of RNA polymerase found in eukaryotes?

Accepted Answer

DNA polymerase

Answer

RNA polymerase I

Answer

RNA polymerase II

Answer

RNA polymerase III

Question 6

What is the process by which mRNA is synthesized using a DNA template called?

Accepted Answer

Transcription

Answer

Replication

Answer

Translation

Answer

Condensation

Question 7

Which of the following is not a post-transcriptional modification that occurs in eukaryotes?

Accepted Answer

Phosphorylation

Answer

Splicing

Answer

Capping

Answer

Polyadenylation

Question 8

Which of the following does not affect the rate of transcription?

Accepted Answer

Number of ribosomes

Answer

Promoter strength

Answer

Transcription factor binding

Answer

Helicase activity

Question 9

What is the sequence of nucleotides in the anticodon of a tRNA that will bind to the codon AUG on an mRNA?

Accepted Answer

UAC

Answer

TAC

Answer

CAU

Answer

AUG

Question 10

Which statement about gene expression is accurate?

Accepted Answer

Gene expression can be regulated at different stages.

Answer

Gene expression is always a unidirectional process.

Answer

All genes are expressed equally in all cells.

Answer

Gene expression is unaffected by environmental factors.

Question 11

What is the enzyme responsible for catalyzing the polymerization of amino acids into a polypeptide chain?

Accepted Answer

Peptidyl transferase

Answer

Aminoacyl synthetase

Answer

Protease

Answer

Polymerase

Question 12

How do post-transcriptional modifications contribute to regulating gene expression?

Accepted Answer

They influence the stability and location of mRNA molecules.

Answer

They solely remove introns from pre-mRNA.

Answer

They are not necessary for mRNA translation.

Answer

They have no role in regulating gene expression at the protein level.

Question 13

Which components are essential to the regulatory region of a eukaryotic gene?

Accepted Answer

Promoter, enhancer, silencer

Answer

Exon, intron, codon

Answer

Operator, repressor, inducer

Answer

Telomere, centromere, origin of replication

Question 14

How does CRISPR-Cas9 gene editing technology enable precise regulation of gene expression?

Accepted Answer

CRISPR-Cas9 allows targeted DNA modification, facilitating precise control over gene expression.

Answer

CRISPR-Cas9 is primarily used for gene knockout, with limited applications in gene expression regulation.

Answer

CRISPR-Cas9 technology is not yet suitable for human gene therapy due to safety concerns.

Question 15

Which of the following accurately describes the key steps and regulatory mechanisms involved in RNA processing?

Accepted Answer

RNA processing includes 5' capping, intron removal through splicing, and 3' polyadenylation.

Accepted Answer

Regulatory mechanisms like alternative splicing and RNA editing generate diverse protein isoforms.

Answer

Capping, polyadenylation, and splicing occur during transcription and are not subject to regulation.

Answer

RNA processing is essential for eukaryotic genes but not for prokaryotic gene expression.

Question 16

How do transcription factors control gene expression?

Accepted Answer

By binding to specific DNA sequences and affecting promoter accessibility

Answer

By altering the DNA structure directly

Answer

By binding to RNA polymerase and preventing it from reaching promoters

Answer

By initiating the translation process

Question 17

Which enzyme is responsible for separating the DNA strands during transcription?

Accepted Answer

Helicase

Answer

RNA polymerase

Answer

Primase

Question 18

What is the definition of gene expression?

Accepted Answer

The process of converting DNA to RNA and then RNA to proteins.

Answer

The process of copying DNA to create new DNA molecules.

Answer

The process of converting RNA to DNA.

Question 19

Which RNA polymerase is responsible for synthesizing messenger RNA (mRNA) in eukaryotic cells?

Accepted Answer

RNA polymerase II

Answer

RNA polymerase I

Answer

RNA polymerase IV

Answer

RNA polymerase III

Question 20

What is the primary function of the ribosome during gene expression?

Accepted Answer

Facilitate protein synthesis by assembling amino acids

Answer

Process and modify RNA molecules

Answer

Transcribe DNA into RNA

Answer

Replicate DNA

Question 21

Which component is NOT part of the translation initiation complex in eukaryotes?

Accepted Answer

RNA polymerase

Answer

mRNA

Answer

Initiator tRNA

Answer

Small ribosomal subunit

Question 22

How many different amino acids are encoded by the genetic code?

Accepted Answer

20

Answer

16

Answer

24

Answer

28

Question 23

What is the primary consequence of a nonsense mutation in a gene?

Accepted Answer

Premature termination of protein synthesis

Answer

No impact on protein synthesis

Answer

Increased gene expression

Answer

Production of an altered protein

Question 24

What is the function of sigma factor in bacterial transcription?

Accepted Answer

Assists RNA polymerase in recognizing and binding to the promoter region

Answer

Modifies RNA transcripts after synthesis

Answer

Catalyzes the synthesis of RNA

Question 25

What is the primary function of the Shine-Dalgarno sequence found in prokaryotes?

Accepted Answer

Facilitates the binding of the ribosome to the mRNA

Answer

Processes tRNA molecules

Answer

Promotes transcription initiation

Answer

Terminates translation

Question 26

What is the term for the process by which a gene is permanently inactivated or 'turned off'?

Accepted Answer

Gene silencing

Answer

Gene therapy

Answer

Gene editing

Answer

Gene regulation

Question 27

Which of the following enzymes synthesizes RNA from a DNA template?

Accepted Answer

RNA polymerase

Answer

Primase

Answer

Reverse transcriptase

Answer

Helicase

Question 28

What is the primary function of ribosomes?

Accepted Answer

Site of protein synthesis

Answer

Storage of genetic material

Answer

Regulation of gene expression

Question 29

Which type of RNA molecule carries amino acids to the ribosome during protein synthesis?

Accepted Answer

tRNA

Answer

mRNA

Answer

snRNA

Answer

rRNA

Question 30

What is the process by which DNA is copied into RNA?

Accepted Answer

Transcription

Answer

Translation

Answer

Replication

Answer

Mutation

Question 31

What is the primary role of RNA polymerase in transcription?

Accepted Answer

Synthesizes mRNA from a DNA template

Answer

Unwinds the DNA double helix

Answer

Adds a poly(A) tail to mRNA

Answer

Removes introns from pre-mRNA

Question 32

Which of the following is a key step in translation?

Accepted Answer

Formation of peptide bonds

Answer

Processing of pre-mRNA

Answer

Synthesis of mRNA

Answer

DNA replication

Question 33

What is the function of an operon?

Accepted Answer

Coordinate the expression of multiple genes

Answer

Initiate translation

Answer

Terminate transcription

Answer

Process pre-mRNA

Question 34

Which type of RNA modification occurs after transcription?

Accepted Answer

Splicing

Answer

Replication

Answer

Translation

Answer

Transcription

Question 35

What is the characteristic of introns in eukaryotic genes?

Accepted Answer

Non-coding regions removed during splicing

Answer

Promoter regions that regulate gene expression

Answer

Coding regions translated into protein

Question 36

Which enzyme is responsible for catalyzing the synthesis of RNA from a DNA template?

Accepted Answer

RNA polymerase

Answer

Primase

Answer

DNA polymerase

Answer

Exonuclease

Question 37

What is the nitrogenous base that replaces thymine in RNA?

Accepted Answer

Uracil

Answer

Guanine

Answer

Adenine

Answer

Cytosine

Question 38

Which type of RNA carries genetic information from the nucleus to the ribosome?

Accepted Answer

Messenger RNA (mRNA)

Answer

Transfer RNA (tRNA)

Answer

Ribosomal RNA (rRNA)

Answer

Small interfering RNA (siRNA)

Question 39

Where does translation, the process of protein synthesis, take place in the cell?

Accepted Answer

Ribosomes

Answer

Golgi apparatus

Answer

Mitochondria

Answer

Nucleus

Question 40

Which amino acid is specified by the codon UUU?

Accepted Answer

Phenylalanine

Answer

Leucine

Answer

Glycine

Answer

Serine

Question 41

What is the role of tRNA in translation?

Accepted Answer

To bring specific amino acids to the ribosome

Answer

To carry genetic information from the nucleus

Answer

To form the ribosome structure

Answer

To catalyze the formation of peptide bonds

Question 42

What is the process by which a cell turns off the expression of a particular gene?

Accepted Answer

Gene silencing

Answer

Gene duplication

Answer

Gene amplification

Answer

Gene mutation

Question 43

What is the potential impact of gene expression studies on human health?

Accepted Answer

Identifying genetic markers for diseases and developing personalized treatments

Answer

Creating genetically modified organisms for food production

Answer

Developing new biofuels

Question 44

During transcription, which enzyme is responsible for synthesizing mRNA from DNA?

Accepted Answer

RNA polymerase

Answer

DNA ligase

Answer

Reverse transcriptase

Answer

Helicase

Question 45

In eukaryotic cells, where does transcription predominantly occur?

Accepted Answer

Nucleus

Answer

Mitochondria

Answer

Cytoplasm

Answer

Golgi apparatus

Question 46

Which of the following is NOT a step involved in transcription?

Accepted Answer

Splicing

Answer

Elongation

Answer

Initiation

Answer

Termination

Question 47

During translation, which type of RNA carries amino acids to the ribosome?

Accepted Answer

Transfer RNA (tRNA)

Answer

Messenger RNA (mRNA)

Answer

Ribosomal RNA (rRNA)

Answer

Small nuclear RNA (snRNA)

Question 48

In eukaryotic cells, where does protein synthesis primarily occur?

Accepted Answer

Ribosome

Answer

Lysosome

Answer

Mitochondria

Answer

Endoplasmic reticulum

Question 49

Which codon in the mRNA sequence codes for the initiation of protein synthesis?

Accepted Answer

AUG

Answer

UAA

Answer

UCA

Question 50

What is the term for the process that converts mRNA into a protein?

Accepted Answer

Translation

Answer

Replication

Answer

Transcription

Answer

Mutation

Question 51

Which of the following is an example of a post-translational modification?

Accepted Answer

Phosphorylation

Answer

Translation

Answer

Transcription

Answer

Replication

Question 52

What is the primary function of a promoter in gene expression?

Accepted Answer

To regulate the initiation of transcription

Answer

To translate mRNA

Answer

To terminate transcription

Answer

To synthesize mRNA