BIO 250 Final Exam — Exam Questions with
Correct Answers (VerifiedAnswers) Plus
Rationales 2026 Q&A Instant Download PDF
Question 1
Which statement best describes the primary function of the
plasma membrane?
A. It produces ATP for cellular activities.
B. It stores the cell's genetic information.
C. It regulates the movement of substances into and out of the
cell.
D. It synthesizes proteins for secretion.
Rationale: The plasma membrane is a selectively permeable
phospholipid bilayer that controls what enters and leaves the
cell. Membrane proteins contribute to transport, signaling,
recognition, and cell adhesion. ATP production primarily occurs
in mitochondria, genetic information is stored primarily in the
nucleus of eukaryotic cells, and protein synthesis occurs at
ribosomes.
Question 2
,Which organelle is primarily responsible for producing ATP
through aerobic cellular respiration?
A. Golgi apparatus
B. Lysosome
C. Endoplasmic reticulum
D. Mitochondrion
Rationale: Mitochondria are the principal sites of aerobic ATP
production in eukaryotic cells. The citric acid cycle occurs in the
mitochondrial matrix, while the electron transport chain and
oxidative phosphorylation occur across the inner mitochondrial
membrane. The Golgi modifies and sorts proteins, lysosomes
digest cellular materials, and the endoplasmic reticulum
participates in protein and lipid processing.
Question 3
What is the primary function of ribosomes?
A. DNA replication
B. Lipid digestion
C. Protein synthesis
D. ATP storage
Rationale: Ribosomes translate messenger RNA into polypeptide
chains by joining amino acids in the sequence specified by the
genetic code. Ribosomes may be free in the cytoplasm or
,attached to rough endoplasmic reticulum. DNA replication
occurs through specialized enzymes such as DNA polymerases,
while ATP is produced and utilized rather than stored as a
primary ribosomal function.
Question 4
Which type of transport requires cellular energy in the form of
ATP?
A. Simple diffusion
B. Osmosis
C. Facilitated diffusion
D. Active transport
Rationale: Active transport moves substances against their
concentration or electrochemical gradients and therefore
requires energy. A classic example is the sodium-potassium
pump, which uses ATP to move sodium ions out of a cell and
potassium ions into it. Simple diffusion, osmosis, and facilitated
diffusion are forms of passive transport and do not directly
require ATP.
Question 5
A cell placed in a hypotonic solution will generally:
, A. Lose water and shrink.
B. Remain unchanged because water cannot cross membranes.
C. Gain water and may swell.
D. Immediately undergo DNA replication.
Rationale: A hypotonic solution has a lower solute concentration
than the cell's interior. Water therefore moves into the cell by
osmosis. In animal cells, excessive water entry can cause
swelling and potentially lysis. Plant cells generally become
turgid because their cell walls provide structural support.
Question 6
Which molecule carries genetic information from DNA to
ribosomes for protein synthesis?
A. ATP
B. tRNA
C. rRNA
D. mRNA
Rationale: Messenger RNA, or mRNA, is transcribed from DNA
and carries the encoded instructions to ribosomes. Transfer RNA
brings specific amino acids to the ribosome, while ribosomal
RNA is a structural and catalytic component of ribosomes. ATP
primarily functions as an energy-transfer molecule.
Correct Answers (VerifiedAnswers) Plus
Rationales 2026 Q&A Instant Download PDF
Question 1
Which statement best describes the primary function of the
plasma membrane?
A. It produces ATP for cellular activities.
B. It stores the cell's genetic information.
C. It regulates the movement of substances into and out of the
cell.
D. It synthesizes proteins for secretion.
Rationale: The plasma membrane is a selectively permeable
phospholipid bilayer that controls what enters and leaves the
cell. Membrane proteins contribute to transport, signaling,
recognition, and cell adhesion. ATP production primarily occurs
in mitochondria, genetic information is stored primarily in the
nucleus of eukaryotic cells, and protein synthesis occurs at
ribosomes.
Question 2
,Which organelle is primarily responsible for producing ATP
through aerobic cellular respiration?
A. Golgi apparatus
B. Lysosome
C. Endoplasmic reticulum
D. Mitochondrion
Rationale: Mitochondria are the principal sites of aerobic ATP
production in eukaryotic cells. The citric acid cycle occurs in the
mitochondrial matrix, while the electron transport chain and
oxidative phosphorylation occur across the inner mitochondrial
membrane. The Golgi modifies and sorts proteins, lysosomes
digest cellular materials, and the endoplasmic reticulum
participates in protein and lipid processing.
Question 3
What is the primary function of ribosomes?
A. DNA replication
B. Lipid digestion
C. Protein synthesis
D. ATP storage
Rationale: Ribosomes translate messenger RNA into polypeptide
chains by joining amino acids in the sequence specified by the
genetic code. Ribosomes may be free in the cytoplasm or
,attached to rough endoplasmic reticulum. DNA replication
occurs through specialized enzymes such as DNA polymerases,
while ATP is produced and utilized rather than stored as a
primary ribosomal function.
Question 4
Which type of transport requires cellular energy in the form of
ATP?
A. Simple diffusion
B. Osmosis
C. Facilitated diffusion
D. Active transport
Rationale: Active transport moves substances against their
concentration or electrochemical gradients and therefore
requires energy. A classic example is the sodium-potassium
pump, which uses ATP to move sodium ions out of a cell and
potassium ions into it. Simple diffusion, osmosis, and facilitated
diffusion are forms of passive transport and do not directly
require ATP.
Question 5
A cell placed in a hypotonic solution will generally:
, A. Lose water and shrink.
B. Remain unchanged because water cannot cross membranes.
C. Gain water and may swell.
D. Immediately undergo DNA replication.
Rationale: A hypotonic solution has a lower solute concentration
than the cell's interior. Water therefore moves into the cell by
osmosis. In animal cells, excessive water entry can cause
swelling and potentially lysis. Plant cells generally become
turgid because their cell walls provide structural support.
Question 6
Which molecule carries genetic information from DNA to
ribosomes for protein synthesis?
A. ATP
B. tRNA
C. rRNA
D. mRNA
Rationale: Messenger RNA, or mRNA, is transcribed from DNA
and carries the encoded instructions to ribosomes. Transfer RNA
brings specific amino acids to the ribosome, while ribosomal
RNA is a structural and catalytic component of ribosomes. ATP
primarily functions as an energy-transfer molecule.
