BIOL 271 MODULE 2 EXAM QUESTIONS
AND ANSWERS
1. Which of the following molecules acts as a buffer against changes in membrane fluidity in
eukaryotic cells?
A. Phospholipids
B. Glycoproteins
C. Cholesterol
D. Peripheral proteins
Answer: C
Conceptual Explanation: Cholesterol hinders the close packing of phospholipids at low
temperatures and limits their movement at high temperatures, effectively acting as a
fluidity buffer.
2. In the context of the fluid mosaic model, what describes the ‘mosaic’ aspect?
A. The diverse protein molecules embedded in the bilayer
B. The aqueous environment
C. The movement of lipids
D. The presence of carbohydrate chains only
,Answer: A
Conceptual Explanation: The ‘mosaic’ refers to the various proteins embedded in or
attached to the lipid bilayer, similar to tiles in a mosaic artwork.
3. Which transport mechanism moves solutes against their concentration gradient using ATP?
A. Facilitated diffusion
B. Osmosis
C. Simple diffusion
D. Active transport
Answer: D
Conceptual Explanation: Active transport requires energy (ATP) to move substances
against their concentration gradient, whereas passive processes do not.
4. What is the primary function of the nucleolus?
A. DNA replication
B. Ribosomal RNA (rRNA) synthesis
C. Protein folding
D. Lipid synthesis
Answer: B
, Conceptual Explanation: The nucleolus is the site within the nucleus where rRNA is
synthesized and ribosomal subunits are assembled.
5. Which organelle is responsible for the detoxification of drugs and poisons, especially in
liver cells?
A. Rough Endoplasmic Reticulum
B. Golgi Apparatus
C. Lysosomes
D. Smooth Endoplasmic Reticulum
Answer: D
Conceptual Explanation: The smooth ER contains enzymes that catalyze the
detoxification of drugs and poisons.
6. A cell placed in a hypertonic solution will typically:
A. Swell and burst
B. Remain the same size
C. Divide rapidly
D. Shrivel (crenate)
Answer: D
Conceptual Explanation: In a hypertonic solution, water leaves the cell by osmosis to
follow the higher solute concentration outside, causing the cell to shrivel.
AND ANSWERS
1. Which of the following molecules acts as a buffer against changes in membrane fluidity in
eukaryotic cells?
A. Phospholipids
B. Glycoproteins
C. Cholesterol
D. Peripheral proteins
Answer: C
Conceptual Explanation: Cholesterol hinders the close packing of phospholipids at low
temperatures and limits their movement at high temperatures, effectively acting as a
fluidity buffer.
2. In the context of the fluid mosaic model, what describes the ‘mosaic’ aspect?
A. The diverse protein molecules embedded in the bilayer
B. The aqueous environment
C. The movement of lipids
D. The presence of carbohydrate chains only
,Answer: A
Conceptual Explanation: The ‘mosaic’ refers to the various proteins embedded in or
attached to the lipid bilayer, similar to tiles in a mosaic artwork.
3. Which transport mechanism moves solutes against their concentration gradient using ATP?
A. Facilitated diffusion
B. Osmosis
C. Simple diffusion
D. Active transport
Answer: D
Conceptual Explanation: Active transport requires energy (ATP) to move substances
against their concentration gradient, whereas passive processes do not.
4. What is the primary function of the nucleolus?
A. DNA replication
B. Ribosomal RNA (rRNA) synthesis
C. Protein folding
D. Lipid synthesis
Answer: B
, Conceptual Explanation: The nucleolus is the site within the nucleus where rRNA is
synthesized and ribosomal subunits are assembled.
5. Which organelle is responsible for the detoxification of drugs and poisons, especially in
liver cells?
A. Rough Endoplasmic Reticulum
B. Golgi Apparatus
C. Lysosomes
D. Smooth Endoplasmic Reticulum
Answer: D
Conceptual Explanation: The smooth ER contains enzymes that catalyze the
detoxification of drugs and poisons.
6. A cell placed in a hypertonic solution will typically:
A. Swell and burst
B. Remain the same size
C. Divide rapidly
D. Shrivel (crenate)
Answer: D
Conceptual Explanation: In a hypertonic solution, water leaves the cell by osmosis to
follow the higher solute concentration outside, causing the cell to shrivel.
