BIOD 102 MODULE 1 EXAM 2026/2027 | Essential Biology II
with Lab | Verified Q&A | Grade A | Portage Learning | Pass
Guaranteed - A+ Graded
SECTION 1: GENE EXPRESSION & REGULATION (15 Questions)
Q1: Which epigenetic modification to histone proteins is associated with an INCREASE
in transcriptional activity?
A. Methylation of histone tails [CORRECT]
B. Acetylation of histone tails
C. Phosphorylation of DNA polymerase
D. Ubiquitination of ribosomal subunits
Correct Answer: A
Rationale: Histone acetylation neutralizes positive charges on histones, loosening
chromatin structure and promoting transcription. Methylation can either activate or
repress depending on location, but acetylation is the primary activator; phosphorylation
and ubiquitination are not the primary histone modifications for transcriptional
activation. VERIFIED ✓ Portage Learning BIOD 102 Module 1: Gene Expression &
Regulation.
Q2: A repressor protein binds to the operator region of an operon. What is the most
likely effect on transcription?
A. Transcription increases because RNA polymerase is stabilized
B. Transcription decreases because RNA polymerase cannot bind effectively [CORRECT]
C. Translation is inhibited because ribosomes cannot attach to mRNA
D. Splicing is prevented because introns cannot be removed
Correct Answer: B
Rationale: Repressor proteins bind to operator sequences and physically block RNA
polymerase from transcribing the structural genes, thereby decreasing transcription.
They do not affect translation or splicing directly. VERIFIED ✓ Portage Learning BIOD
102 Module 1: Prokaryotic Gene Regulation.
,Q3: Alternative splicing allows a single gene to produce multiple protein isoforms. At
what level of gene expression does this regulatory mechanism occur?
A. Pre-transcriptional regulation
B. Post-transcriptional regulation [CORRECT]
C. Post-translational regulation
D. Translational regulation
Correct Answer: B
Rationale: Alternative splicing occurs after transcription (post-transcriptional) when
introns are removed and exons are joined in different combinations from the pre-mRNA
transcript. It does not occur at the DNA or protein level. VERIFIED ✓ Portage Learning
BIOD 102 Module 1: Eukaryotic Gene Regulation.
Q4: Which of the following is a post-translational mechanism that regulates protein
levels within a cell?
A. Addition of a 5' cap to pre-mRNA
B. Addition of a poly-A tail to mRNA
C. Selective degradation of proteins by proteasomes [CORRECT]
D. Alternative splicing of exons
Correct Answer: C
Rationale: Selective protein degradation via ubiquitin-proteasome pathways is a
post-translational regulatory mechanism. The 5' cap, poly-A tail, and alternative splicing
are all post-transcriptional modifications, not post-translational. VERIFIED ✓ Portage
Learning BIOD 102 Module 1: Levels of Gene Regulation.
Q5: During transcription initiation in eukaryotes, which DNA sequence does the
TATA-binding protein (TBP) recognize?
A. The promoter region containing the TATA box [CORRECT]
B. The terminator sequence downstream of the gene
C. The enhancer region located thousands of base pairs away
D. The origin of replication for DNA polymerase
Correct Answer: A
Rationale: The TATA-binding protein (TBP) is a transcription factor that binds
specifically to the TATA box within the promoter region to recruit RNA polymerase II and
initiate transcription. It does not bind terminators, enhancers, or origins of replication.
VERIFIED ✓ Portage Learning BIOD 102 Module 1: Transcription.
, Q6: Which of the following best describes the function of activator proteins in
eukaryotic gene regulation?
A. They bind to operators and block RNA polymerase
B. They increase the rate of transcription by binding to enhancer regions [CORRECT]
C. They remove introns from pre-mRNA transcripts
D. They add methyl groups to DNA to silence genes
Correct Answer: B
Rationale: Activator proteins bind to enhancer DNA sequences and interact with
transcription machinery to increase transcription rates. Repressors decrease
transcription; splicing removes introns; DNA methylation typically silences genes.
VERIFIED ✓ Portage Learning BIOD 102 Module 1: Eukaryotic Transcription Factors.
Q7: A scientist treats cells with a drug that inhibits histone deacetylase (HDAC)
enzymes. What effect would this most likely have on gene expression?
A. Increased gene expression because acetyl groups remain on histones [CORRECT]
B. Decreased gene expression because histones become tightly packed
C. No effect because HDAC inhibitors do not affect chromatin structure
D. Decreased gene expression because DNA becomes methylated
Correct Answer: A
Rationale: HDAC enzymes remove acetyl groups from histones. Inhibiting HDACs
maintains histone acetylation, which keeps chromatin in an open, transcriptionally
active state (euchromatin), thereby increasing gene expression. VERIFIED ✓ Portage
Learning BIOD 102 Module 1: Epigenetic Regulation.
Q8: In the lac operon of E. coli, when lactose is absent, what is the state of the repressor
protein and the operon?
A. The repressor is inactive and the operon is transcribed
B. The repressor is active and binds to the operator, blocking transcription [CORRECT]
C. The repressor is degraded and the operon is constitutively active
D. The repressor binds to the promoter and enhances transcription
Correct Answer: B
Rationale: In the absence of lactose, the lac repressor protein is in its active
conformation and binds to the operator sequence, preventing RNA polymerase from
transcribing the lac genes. Lactose (allolactose) inactivates the repressor. VERIFIED ✓
Portage Learning BIOD 102 Module 1: Prokaryotic Operons.
with Lab | Verified Q&A | Grade A | Portage Learning | Pass
Guaranteed - A+ Graded
SECTION 1: GENE EXPRESSION & REGULATION (15 Questions)
Q1: Which epigenetic modification to histone proteins is associated with an INCREASE
in transcriptional activity?
A. Methylation of histone tails [CORRECT]
B. Acetylation of histone tails
C. Phosphorylation of DNA polymerase
D. Ubiquitination of ribosomal subunits
Correct Answer: A
Rationale: Histone acetylation neutralizes positive charges on histones, loosening
chromatin structure and promoting transcription. Methylation can either activate or
repress depending on location, but acetylation is the primary activator; phosphorylation
and ubiquitination are not the primary histone modifications for transcriptional
activation. VERIFIED ✓ Portage Learning BIOD 102 Module 1: Gene Expression &
Regulation.
Q2: A repressor protein binds to the operator region of an operon. What is the most
likely effect on transcription?
A. Transcription increases because RNA polymerase is stabilized
B. Transcription decreases because RNA polymerase cannot bind effectively [CORRECT]
C. Translation is inhibited because ribosomes cannot attach to mRNA
D. Splicing is prevented because introns cannot be removed
Correct Answer: B
Rationale: Repressor proteins bind to operator sequences and physically block RNA
polymerase from transcribing the structural genes, thereby decreasing transcription.
They do not affect translation or splicing directly. VERIFIED ✓ Portage Learning BIOD
102 Module 1: Prokaryotic Gene Regulation.
,Q3: Alternative splicing allows a single gene to produce multiple protein isoforms. At
what level of gene expression does this regulatory mechanism occur?
A. Pre-transcriptional regulation
B. Post-transcriptional regulation [CORRECT]
C. Post-translational regulation
D. Translational regulation
Correct Answer: B
Rationale: Alternative splicing occurs after transcription (post-transcriptional) when
introns are removed and exons are joined in different combinations from the pre-mRNA
transcript. It does not occur at the DNA or protein level. VERIFIED ✓ Portage Learning
BIOD 102 Module 1: Eukaryotic Gene Regulation.
Q4: Which of the following is a post-translational mechanism that regulates protein
levels within a cell?
A. Addition of a 5' cap to pre-mRNA
B. Addition of a poly-A tail to mRNA
C. Selective degradation of proteins by proteasomes [CORRECT]
D. Alternative splicing of exons
Correct Answer: C
Rationale: Selective protein degradation via ubiquitin-proteasome pathways is a
post-translational regulatory mechanism. The 5' cap, poly-A tail, and alternative splicing
are all post-transcriptional modifications, not post-translational. VERIFIED ✓ Portage
Learning BIOD 102 Module 1: Levels of Gene Regulation.
Q5: During transcription initiation in eukaryotes, which DNA sequence does the
TATA-binding protein (TBP) recognize?
A. The promoter region containing the TATA box [CORRECT]
B. The terminator sequence downstream of the gene
C. The enhancer region located thousands of base pairs away
D. The origin of replication for DNA polymerase
Correct Answer: A
Rationale: The TATA-binding protein (TBP) is a transcription factor that binds
specifically to the TATA box within the promoter region to recruit RNA polymerase II and
initiate transcription. It does not bind terminators, enhancers, or origins of replication.
VERIFIED ✓ Portage Learning BIOD 102 Module 1: Transcription.
, Q6: Which of the following best describes the function of activator proteins in
eukaryotic gene regulation?
A. They bind to operators and block RNA polymerase
B. They increase the rate of transcription by binding to enhancer regions [CORRECT]
C. They remove introns from pre-mRNA transcripts
D. They add methyl groups to DNA to silence genes
Correct Answer: B
Rationale: Activator proteins bind to enhancer DNA sequences and interact with
transcription machinery to increase transcription rates. Repressors decrease
transcription; splicing removes introns; DNA methylation typically silences genes.
VERIFIED ✓ Portage Learning BIOD 102 Module 1: Eukaryotic Transcription Factors.
Q7: A scientist treats cells with a drug that inhibits histone deacetylase (HDAC)
enzymes. What effect would this most likely have on gene expression?
A. Increased gene expression because acetyl groups remain on histones [CORRECT]
B. Decreased gene expression because histones become tightly packed
C. No effect because HDAC inhibitors do not affect chromatin structure
D. Decreased gene expression because DNA becomes methylated
Correct Answer: A
Rationale: HDAC enzymes remove acetyl groups from histones. Inhibiting HDACs
maintains histone acetylation, which keeps chromatin in an open, transcriptionally
active state (euchromatin), thereby increasing gene expression. VERIFIED ✓ Portage
Learning BIOD 102 Module 1: Epigenetic Regulation.
Q8: In the lac operon of E. coli, when lactose is absent, what is the state of the repressor
protein and the operon?
A. The repressor is inactive and the operon is transcribed
B. The repressor is active and binds to the operator, blocking transcription [CORRECT]
C. The repressor is degraded and the operon is constitutively active
D. The repressor binds to the promoter and enhances transcription
Correct Answer: B
Rationale: In the absence of lactose, the lac repressor protein is in its active
conformation and binds to the operator sequence, preventing RNA polymerase from
transcribing the lac genes. Lactose (allolactose) inactivates the repressor. VERIFIED ✓
Portage Learning BIOD 102 Module 1: Prokaryotic Operons.
