BIOL 251 MODULE 4 EXAM 2026/2027 | COMPLETE
QUESTIONS AND ANSWERS (VERIFIED ANSWERS) |
EXAM PREP | COMPREHENSIVE EXAM GUIDE
2026&2027
1. Which statement best describes the primary function of the cell membrane?
A. It stores genetic information
B. It regulates movement of substances into and out of the cell
C. It synthesizes all cellular proteins
D. It produces ATP directly
Answer: B
The cell membrane is selectively permeable, allowing some substances to cross while
restricting others. This regulation helps maintain cellular homeostasis.
2. A red blood cell is placed in a solution with a lower solute concentration than the cell.
What is most likely to occur?
A. Water moves into the cell
B. Water moves out of the cell
C. Solutes leave until equilibrium is reached
D. The cell actively pumps water outward
Answer: A
The surrounding solution is hypotonic relative to the cell, so water enters the cell by osmosis.
3. Which process requires cellular energy to move a substance against its concentration
gradient?
A. Simple diffusion
B. Osmosis
C. Facilitated diffusion
D. Active transport
Answer: D
Active transport uses cellular energy, usually ATP, to move substances against their
concentration gradients.
,4. A researcher observes that glucose enters a cell through a membrane protein without
direct ATP consumption. Which transport mechanism is most likely involved?
A. Phagocytosis
B. Simple diffusion
C. Facilitated diffusion
D. Primary active transport
Answer: C
Facilitated diffusion moves substances down their concentration gradients through
membrane proteins without directly requiring ATP.
5. Which organelle is primarily responsible for producing ATP through aerobic cellular
respiration?
A. Golgi apparatus
B. Mitochondrion
C. Lysosome
D. Nucleolus
Answer: B
Mitochondria contain the enzymes and electron transport machinery required for most
aerobic ATP production.
6. A cell has a mutation that prevents ribosomes from functioning properly. Which process
would be most directly affected?
A. Protein synthesis
B. DNA replication
C. Lipid storage
D. Cellular respiration
Answer: A
Ribosomes translate messenger RNA into polypeptide chains, making them essential for
protein synthesis.
7. Which molecule carries genetic information from DNA to a ribosome during protein
synthesis?
A. tRNA
B. rRNA
C. mRNA
D. ATP
,Answer: C
Messenger RNA carries the genetic instructions transcribed from DNA to the ribosome for
translation.
8. During DNA replication, which enzyme adds complementary nucleotides to the growing
DNA strand?
A. DNA polymerase
B. RNA polymerase
C. Ligase
D. Helicase
Answer: A
DNA polymerase adds complementary nucleotides to the newly synthesized DNA strand and
helps maintain replication accuracy.
9. What is the primary role of helicase during DNA replication?
A. Joining Okazaki fragments
B. Adding RNA primers
C. Separating the DNA strands
D. Replacing damaged nucleotides
Answer: C
Helicase unwinds the DNA double helix by breaking the hydrogen bonds between
complementary bases.
10. Which nitrogenous base pairs with adenine in DNA?
A. Cytosine
B. Guanine
C. Uracil
D. Thymine
Answer: D
In DNA, adenine forms complementary hydrogen bonds with thymine.
11. Which feature distinguishes RNA from DNA?
A. RNA contains ribose sugar
B. RNA contains thymine instead of uracil
, C. RNA is always double stranded
D. RNA cannot contain nucleotide bases
Answer: A
RNA contains ribose sugar and normally uses uracil instead of thymine.
12. A mutation changes a DNA nucleotide but does not alter the resulting amino acid. What
type of mutation is this?
A. Frameshift mutation
B. Silent mutation
C. Nonsense mutation
D. Missense mutation
Answer: B
A silent mutation changes a nucleotide sequence without changing the amino acid encoded
by the affected codon.
13. Which mutation is most likely to alter every codon downstream of the mutation site?
A. Silent mutation
B. Point substitution
C. Frameshift mutation
D. Neutral mutation
Answer: C
Insertion or deletion of nucleotides in numbers not divisible by three shifts the reading frame
and can alter downstream codons.
14. During transcription, genetic information is transferred from:
A. DNA to RNA
B. RNA to DNA
C. Protein to RNA
D. RNA to protein
Answer: A
Transcription uses a DNA template to produce an RNA molecule, usually messenger RNA.
15. Translation occurs primarily at the:
QUESTIONS AND ANSWERS (VERIFIED ANSWERS) |
EXAM PREP | COMPREHENSIVE EXAM GUIDE
2026&2027
1. Which statement best describes the primary function of the cell membrane?
A. It stores genetic information
B. It regulates movement of substances into and out of the cell
C. It synthesizes all cellular proteins
D. It produces ATP directly
Answer: B
The cell membrane is selectively permeable, allowing some substances to cross while
restricting others. This regulation helps maintain cellular homeostasis.
2. A red blood cell is placed in a solution with a lower solute concentration than the cell.
What is most likely to occur?
A. Water moves into the cell
B. Water moves out of the cell
C. Solutes leave until equilibrium is reached
D. The cell actively pumps water outward
Answer: A
The surrounding solution is hypotonic relative to the cell, so water enters the cell by osmosis.
3. Which process requires cellular energy to move a substance against its concentration
gradient?
A. Simple diffusion
B. Osmosis
C. Facilitated diffusion
D. Active transport
Answer: D
Active transport uses cellular energy, usually ATP, to move substances against their
concentration gradients.
,4. A researcher observes that glucose enters a cell through a membrane protein without
direct ATP consumption. Which transport mechanism is most likely involved?
A. Phagocytosis
B. Simple diffusion
C. Facilitated diffusion
D. Primary active transport
Answer: C
Facilitated diffusion moves substances down their concentration gradients through
membrane proteins without directly requiring ATP.
5. Which organelle is primarily responsible for producing ATP through aerobic cellular
respiration?
A. Golgi apparatus
B. Mitochondrion
C. Lysosome
D. Nucleolus
Answer: B
Mitochondria contain the enzymes and electron transport machinery required for most
aerobic ATP production.
6. A cell has a mutation that prevents ribosomes from functioning properly. Which process
would be most directly affected?
A. Protein synthesis
B. DNA replication
C. Lipid storage
D. Cellular respiration
Answer: A
Ribosomes translate messenger RNA into polypeptide chains, making them essential for
protein synthesis.
7. Which molecule carries genetic information from DNA to a ribosome during protein
synthesis?
A. tRNA
B. rRNA
C. mRNA
D. ATP
,Answer: C
Messenger RNA carries the genetic instructions transcribed from DNA to the ribosome for
translation.
8. During DNA replication, which enzyme adds complementary nucleotides to the growing
DNA strand?
A. DNA polymerase
B. RNA polymerase
C. Ligase
D. Helicase
Answer: A
DNA polymerase adds complementary nucleotides to the newly synthesized DNA strand and
helps maintain replication accuracy.
9. What is the primary role of helicase during DNA replication?
A. Joining Okazaki fragments
B. Adding RNA primers
C. Separating the DNA strands
D. Replacing damaged nucleotides
Answer: C
Helicase unwinds the DNA double helix by breaking the hydrogen bonds between
complementary bases.
10. Which nitrogenous base pairs with adenine in DNA?
A. Cytosine
B. Guanine
C. Uracil
D. Thymine
Answer: D
In DNA, adenine forms complementary hydrogen bonds with thymine.
11. Which feature distinguishes RNA from DNA?
A. RNA contains ribose sugar
B. RNA contains thymine instead of uracil
, C. RNA is always double stranded
D. RNA cannot contain nucleotide bases
Answer: A
RNA contains ribose sugar and normally uses uracil instead of thymine.
12. A mutation changes a DNA nucleotide but does not alter the resulting amino acid. What
type of mutation is this?
A. Frameshift mutation
B. Silent mutation
C. Nonsense mutation
D. Missense mutation
Answer: B
A silent mutation changes a nucleotide sequence without changing the amino acid encoded
by the affected codon.
13. Which mutation is most likely to alter every codon downstream of the mutation site?
A. Silent mutation
B. Point substitution
C. Frameshift mutation
D. Neutral mutation
Answer: C
Insertion or deletion of nucleotides in numbers not divisible by three shifts the reading frame
and can alter downstream codons.
14. During transcription, genetic information is transferred from:
A. DNA to RNA
B. RNA to DNA
C. Protein to RNA
D. RNA to protein
Answer: A
Transcription uses a DNA template to produce an RNA molecule, usually messenger RNA.
15. Translation occurs primarily at the:
