Gene Expression: A Comprehensive Guide for Biology Students

Question 1

Which of the following is not directly involved in transcription?

Accepted Answer

Spliceosome

Answer

Promoter

Answer

RNA polymerase

Answer

Nucleotides

Question 2

What is the term for the triplet of nucleotides in DNA or RNA that codes for a specific amino acid?

Accepted Answer

Codon

Answer

Anticodon

Answer

Exon

Answer

Intron

Question 3

Which organelle is responsible for protein synthesis in eukaryotic cells?

Accepted Answer

Ribosome

Answer

Mitochondria

Answer

Golgi apparatus

Answer

Nucleus

Question 4

The amino acid sequence of a protein corresponds to its:

Accepted Answer

Primary structure

Answer

Secondary structure

Answer

Tertiary structure

Answer

Quaternary structure

Question 5

The process of synthesizing a complementary RNA molecule from a DNA template is known as:

Accepted Answer

Transcription

Answer

Translation

Answer

Replication

Answer

Reverse transcription

Question 6

Which of the following is a key difference between prokaryotic and eukaryotic transcription?

Accepted Answer

Presence of introns

Answer

Number of RNA polymerases

Answer

Location within the cell

Answer

Use of a promoter

Question 7

The codon that signals the termination of protein synthesis is recognized by:

Accepted Answer

Release factors

Answer

Initiation factors

Answer

Elongation factors

Answer

tRNA molecules

Question 8

The process of converting the genetic information encoded in DNA into a sequence of amino acids is known as:

Accepted Answer

Translation

Answer

Transcription

Answer

Replication

Answer

Gene expression

Question 9

Which enzyme catalyzes the transcription of DNA into RNA?

Accepted Answer

RNA polymerase

Answer

DNA polymerase

Answer

Helicase

Answer

Topoisomerase

Question 10

Which of the following components is responsible for initiating translation?

Accepted Answer

Small ribosomal subunit

Answer

Large ribosomal subunit

Answer

Elongation factor

Answer

Termination factor

Question 11

What role does a promoter play in gene expression?

Accepted Answer

Binding site for RNA polymerase to initiate transcription

Answer

Termination point for transcription

Answer

mRNA splicing site

Answer

Protein translation site

Question 12

What is the primary function of transcription factors in gene expression?

Accepted Answer

Binding to specific DNA sequences to regulate transcription

Answer

Translating mRNA molecules into proteins

Answer

Splicing mRNA molecules

Answer

Polyadenylating mRNA molecules

Question 13

What is the significance of post-translational modifications in gene expression?

Accepted Answer

Modifying protein activity, stability, and localization

Answer

Essential for the proper function of all proteins

Answer

Occurring exclusively in eukaryotic cells

Answer

Being irreversible modifications

Question 14

Which enzyme is responsible for catalyzing RNA synthesis from a DNA template during transcription?

Accepted Answer

RNA polymerase

Answer

DNA polymerase

Answer

Primase

Answer

Ligase

Question 15

What is the primary function of the Shine-Dalgarno sequence in prokaryotic gene expression?

Accepted Answer

Initiates translation

Answer

Enhances transcription efficiency

Answer

Terminates translation

Answer

Promotes DNA replication

Question 16

Which type of mutation results in an amino acid change in the protein it encodes?

Accepted Answer

Missense mutation

Answer

Silent mutation

Answer

Nonsense mutation

Answer

Frameshift mutation

Question 17

Which technique is commonly used to separate and analyze DNA fragments based on size?

Accepted Answer

Gel electrophoresis

Answer

Polymerase chain reaction (PCR)

Answer

DNA sequencing

Answer

Southern blotting

Question 18

What is the main role of transcription factors in gene expression?

Accepted Answer

Regulating the initiation of transcription

Answer

Translating mRNA into proteins

Answer

Processing RNA transcripts

Answer

Replicating DNA

Question 19

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

Accepted Answer

Phosphorylation

Answer

Alternative splicing

Answer

5' capping

Answer

Intron removal

Question 20

State the central dogma of molecular biology.

Accepted Answer

DNA → RNA → Protein

Answer

Protein → RNA → DNA

Answer

RNA → Protein → DNA

Answer

DNA → Protein → RNA

Question 21

What is the primary purpose of gene cloning?

Accepted Answer

Producing multiple copies of a specific gene

Answer

Modifying the function of a gene

Answer

Repairing damaged genes

Answer

Identifying genetic disorders

Question 22

Which of the following is NOT a component of the eukaryotic promoter region?

Accepted Answer

Transcription termination signal

Answer

TATA box

Answer

Initiator element

Answer

Upstream activator sequence

Question 23

What is the primary function of RNA polymerase in transcription?

Accepted Answer

To synthesize the RNA molecule complementary to the DNA template

Answer

To separate the DNA strands

Answer

To modify the RNA molecule after transcription

Answer

To transport the RNA molecule to the cytoplasm

Question 24

What is the central dogma of molecular biology?

Accepted Answer

DNA is transcribed to RNA, which is then translated to proteins

Answer

Proteins are synthesized from RNA, which is then used to produce DNA

Answer

DNA is translated to proteins, which are then used to produce RNA

Answer

RNA is the genetic material of all organisms

Question 25

Which of the following types of RNA molecules is not directly involved in protein synthesis?

Accepted Answer

Small nuclear RNA (snRNA)

Answer

Messenger RNA (mRNA)

Answer

Transfer RNA (tRNA)

Answer

Ribosomal RNA (rRNA)

Question 26

What is the primary role of transcription factors in gene expression?

Accepted Answer

To bind to specific DNA sequences and regulate transcription

Answer

To modify the RNA molecule after transcription

Answer

To synthesize the proteins encoded by genes

Answer

To transport the mRNA molecule to the cytoplasm

Question 27

Examine the structural differences between eukaryotic and prokaryotic mRNAs. Explain how these variations influence gene expression in each cell type.

Accepted Answer

Eukaryotic mRNAs have a 5' cap and a poly-A tail, while prokaryotic mRNAs lack these features.

Accepted Answer

Prokaryotic mRNAs are monocistronic, encoding a single protein, while eukaryotic mRNAs can be polycistronic.

Accepted Answer

Eukaryotic mRNAs undergo RNA processing, including splicing, unlike prokaryotic mRNAs.

Answer

Prokaryotic mRNAs are capped at the 5' end with a methylguanosine residue, unlike eukaryotic mRNAs.

Question 28

Which type of RNA molecule carries the genetic code from DNA to the ribosomes for protein synthesis?

Accepted Answer

Messenger RNA (mRNA)

Answer

Transfer RNA (tRNA)

Answer

Ribosomal RNA (rRNA)

Answer

Small interfering RNA (siRNA)

Question 29

Which characteristic of the genetic code allows for different codons to code for the same amino acid?

Accepted Answer

Redundancy

Answer

Universality

Answer

Unambiguity

Answer

Non-overlapping nature

Question 30

What is the primary function of the ribosome?

Accepted Answer

Protein translation

Answer

DNA replication

Answer

RNA transcription

Answer

mRNA splicing

Question 31

Which type of mutation leads to a frameshift in the reading frame of a protein sequence?

Accepted Answer

Frameshift mutation

Answer

Silent mutation

Answer

Missense mutation

Answer

Nonsense mutation

Question 32

What is the role of the sigma factor in bacterial transcription?

Accepted Answer

Promoter recognition and binding

Answer

mRNA elongation

Answer

RNA polymerase assembly

Answer

Transcription termination

Question 33

How does RNA splicing contribute to the variety of proteins produced?

Accepted Answer

By rearranging exons in different combinations, generating multiple transcripts with distinct protein-coding sequences.

Answer

By removing non-coding regions from the RNA transcript, allowing for translation of a more compact protein.

Answer

By adding chemical modifications to the RNA transcript, influencing its stability and translation efficiency.

Answer

By protecting the RNA transcript from degradation, ensuring its accessibility for translation.

Question 34

Gene expression is regulated at various levels. Name these levels and explain how they can influence gene expression.

Accepted Answer

Transcriptional, post-transcriptional, and translational

Answer

Only transcriptional

Answer

Only translational

Question 35

In the context of gene expression, what is the primary function of transcription?

Accepted Answer

Transferring genetic information from DNA to mRNA

Answer

Synthesizing a protein molecule using an RNA template

Answer

Replicating genetic material from RNA to DNA

Answer

Adding nucleotides to the 3' end of a growing RNA chain

Question 36

Which of the following steps does NOT occur during the elongation phase of translation?

Accepted Answer

Release of the newly synthesized polypeptide chain

Answer

Formation of peptide bonds between adjacent amino acids

Answer

Translocation of the ribosome along the mRNA

Answer

tRNA binding to the appropriate codon on mRNA

Question 37

Which of the following processes involves the synthesis of a messenger RNA (mRNA) molecule from a DNA template?

Accepted Answer

Transcription

Answer

Replication

Answer

Reverse transcription

Answer

Translation

Question 38

In the process of transcription, what is the primary function of RNA polymerase?

Accepted Answer

Catalyzes the synthesis of mRNA complementary to the DNA template strand.

Answer

Separates the DNA strands to expose the template.

Answer

Joins nucleotides during mRNA synthesis.

Answer

Proofreads the mRNA molecule for errors.

Question 39

According to the genetic code, what codon corresponds to the amino acid methionine?

Accepted Answer

AUG

Answer

UUG

Answer

GUG

Answer

UAA

Question 40

Where does protein synthesis primarily occur within eukaryotic cells?

Accepted Answer

Ribosomes

Answer

Mitochondria

Answer

Golgi apparatus

Answer

Endoplasmic reticulum

Question 41

What is the name of the DNA sequence that regulates transcription initiation of a gene?

Accepted Answer

Promoter

Answer

Terminator

Answer

Enhancer

Answer

Operator

Question 42

What is the primary function of microRNAs (miRNAs) in regulating gene expression?

Accepted Answer

Post-transcriptionally regulate gene expression by binding to target mRNAs and inhibiting translation or promoting their degradation.

Answer

Repress translation by binding to the ribosome.

Answer

Activate transcription factors to promote gene expression.

Question 43

Which technique is commonly employed to quantitatively measure gene expression levels?

Accepted Answer

Quantitative real-time PCR

Answer

Gel electrophoresis

Answer

Immunohistochemistry

Answer

Mass spectrometry

Question 44

Which enzyme is responsible for catalyzing the transcription of DNA into RNA?

Accepted Answer

RNA polymerase

Answer

DNA ligase

Answer

Primase

Answer

Helicase

Question 45

What is the name of the process by which mRNA is translated into a protein?

Accepted Answer

Translation

Answer

Transcription

Answer

Replication

Answer

Mutation

Question 46

What is the function of introns?

Accepted Answer

They are non-coding regions that are removed from the mRNA before translation.

Answer

They act as regulatory elements that control gene expression.

Answer

They code for proteins that are essential for cell function.

Question 47

What is the name of the process by which the expression of a gene is turned off?

Accepted Answer

Gene silencing

Answer

Gene activation

Answer

Gene mutation

Question 48

What is the role of ribosomes in gene expression?

Accepted Answer

They assemble proteins during translation.

Answer

They transcribe DNA into mRNA.

Answer

They replicate DNA during cell division.

Answer

They package DNA into chromosomes.

Question 49

What is the term for the sequence of nucleotides in DNA that codes for a specific protein?

Accepted Answer

Gene

Answer

Chromosome

Answer

Genome

Question 50

What is the initial step in the process of gene expression?

Accepted Answer

Transcription

Answer

Replication

Answer

Mutation

Answer

Translation

Question 51

Which enzyme is responsible for synthesizing RNA from a DNA template?

Accepted Answer

RNA polymerase

Answer

Helicase

Answer

DNA polymerase

Answer

Ligase

Question 52

What type of RNA carries the genetic code from DNA to ribosomes for protein synthesis?

Accepted Answer

mRNA

Answer

rRNA

Answer

tRNA

Answer

snRNA

Question 53

Which process involves the formation of a polypeptide chain using an mRNA template?

Accepted Answer

Translation

Answer

Transcription

Answer

Splicing

Answer

Replication

Question 54

Where does the process of translation take place within a cell?

Accepted Answer

Ribosomes

Answer

Golgi apparatus

Answer

Mitochondria

Answer

Nucleus

Question 55

What type of mutation introduces a premature stop codon, resulting in a truncated protein?

Accepted Answer

Nonsense mutation

Answer

Silent mutation

Answer

Frameshift mutation

Answer

Missense mutation

Question 56

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

Accepted Answer

Initiates transcription

Answer

Enhances transcription

Answer

Terminates transcription

Answer

Suppresses transcription

Question 57

Which type of RNA undergoes significant processing, including capping, splicing, and polyadenylation, before becoming functional?

Accepted Answer

pre-mRNA

Answer

rRNA

Answer

mRNA

Answer

tRNA

Question 58

What is the primary role of introns within eukaryotic genes?

Accepted Answer

Non-coding sequences that are removed during splicing

Answer

Coding sequences that are translated into proteins

Answer

Regulatory sequences that control gene expression

Answer

Enhancer sequences that promote transcription