ESTUDYR
PHYSL 210A - CELL PHYSIOLOGY ACTUAL EXAM
QUESTIONS AND ANSWERS
What is the functional unit of life?
A. Organelle
B. Cell
C. Tissue
D. Atom
Rationale: The cell is the smallest unit capable of all life functions.
Where is the plasma membrane located?
A. Surrounding the cell
B. Inside the nucleus
C. Around mitochondria only
D. Within the cytosol
Rationale: The plasma membrane forms the outer barrier of every cell.
Which best describes cytosol?
A. A membrane-bound organelle
B. Extracellular fluid
C. Gel-like fluid suspending organelles
D. The nuclear interior
Rationale: Cytosol is the semi-fluid matrix of the cytoplasm.
Which organelle is the largest in most cells?
A. Mitochondrion
B. Endoplasmic reticulum
C. Nucleus
D. Lysosome
Rationale: The nucleus houses DNA and is typically the cell’s largest structure.
Which statement about organelles is true?
A. All are membrane-bound
B. Some are non-membrane-bound (e.g., ribosomes)
C. None perform specific functions
D. Only the nucleus is membrane-bound
Rationale: Ribosomes and cytoskeleton are non-membrane-bound.
The plasma membrane’s role in communication is via:
A. Gap junctions only
B. Surface receptors binding signaling molecules
C. Phagocytosis
, ESTUDYR
D. DNA transcription
Rationale: Membrane receptors detect extracellular ligands.
Which term means “only certain molecules can cross”?
A. Permeable
B. Impermeable
C. Selectively permeable
D. Freely permeable
Rationale: The membrane restricts passage by size, charge, and solubility.
Phospholipids in water spontaneously form:
A. Micelles
B. Bilayers
C. Tubules
D. Monolayers
Rationale: Amphipathic phospholipids arrange tails inward, heads outward.
Cholesterol in the plasma membrane functions to:
A. Anchor cells together
B. Facilitate active transport
C. Maintain membrane fluidity
D. Form gap junctions
Rationale: Cholesterol buffers fluidity across temperatures.
Glycolipids are found:
A. On the inner mitochondrial membrane
B. Only on the outer plasma membrane leaflet
C. In nuclear pores
D. In the cytosol
Rationale: Carbohydrate-tagged lipids face the extracellular side.
Integral (intrinsic) proteins are typically:
A. Peripheral and water-soluble
B. Amphipathic and embedded in the bilayer
C. Only on the cell surface
D. Enzymes floating in cytosol
Rationale: They span or partially embed in the hydrophobic core.
Tight junctions (occluding junctions) primarily:
A. Anchor cells
B. Prevent paracellular leakage
C. Form channels for ions
D. Transmit electrical signals
Rationale: They seal adjacent membranes to block fluid flow.
PHYSL 210A - CELL PHYSIOLOGY ACTUAL EXAM
QUESTIONS AND ANSWERS
What is the functional unit of life?
A. Organelle
B. Cell
C. Tissue
D. Atom
Rationale: The cell is the smallest unit capable of all life functions.
Where is the plasma membrane located?
A. Surrounding the cell
B. Inside the nucleus
C. Around mitochondria only
D. Within the cytosol
Rationale: The plasma membrane forms the outer barrier of every cell.
Which best describes cytosol?
A. A membrane-bound organelle
B. Extracellular fluid
C. Gel-like fluid suspending organelles
D. The nuclear interior
Rationale: Cytosol is the semi-fluid matrix of the cytoplasm.
Which organelle is the largest in most cells?
A. Mitochondrion
B. Endoplasmic reticulum
C. Nucleus
D. Lysosome
Rationale: The nucleus houses DNA and is typically the cell’s largest structure.
Which statement about organelles is true?
A. All are membrane-bound
B. Some are non-membrane-bound (e.g., ribosomes)
C. None perform specific functions
D. Only the nucleus is membrane-bound
Rationale: Ribosomes and cytoskeleton are non-membrane-bound.
The plasma membrane’s role in communication is via:
A. Gap junctions only
B. Surface receptors binding signaling molecules
C. Phagocytosis
, ESTUDYR
D. DNA transcription
Rationale: Membrane receptors detect extracellular ligands.
Which term means “only certain molecules can cross”?
A. Permeable
B. Impermeable
C. Selectively permeable
D. Freely permeable
Rationale: The membrane restricts passage by size, charge, and solubility.
Phospholipids in water spontaneously form:
A. Micelles
B. Bilayers
C. Tubules
D. Monolayers
Rationale: Amphipathic phospholipids arrange tails inward, heads outward.
Cholesterol in the plasma membrane functions to:
A. Anchor cells together
B. Facilitate active transport
C. Maintain membrane fluidity
D. Form gap junctions
Rationale: Cholesterol buffers fluidity across temperatures.
Glycolipids are found:
A. On the inner mitochondrial membrane
B. Only on the outer plasma membrane leaflet
C. In nuclear pores
D. In the cytosol
Rationale: Carbohydrate-tagged lipids face the extracellular side.
Integral (intrinsic) proteins are typically:
A. Peripheral and water-soluble
B. Amphipathic and embedded in the bilayer
C. Only on the cell surface
D. Enzymes floating in cytosol
Rationale: They span or partially embed in the hydrophobic core.
Tight junctions (occluding junctions) primarily:
A. Anchor cells
B. Prevent paracellular leakage
C. Form channels for ions
D. Transmit electrical signals
Rationale: They seal adjacent membranes to block fluid flow.
