BIO 151 FINAL EXAM 2026 CELL STRUCTURE
AND FUNCTION PRACTICE SET ANSWERS
FULL SOLUTION
◉ Cell Theory.
Answer: All living things are made of cells.
◉ Membrane Structure.
Answer: Phospholipid bilayer: Hydrophobic interior, hydrophilic
exterior.
◉ Membrane Fluidity Influencers.
Answer: Temperature: Higher = more fluid.
◉ Cholesterol in membranes.
Answer: Stabilizes membrane; fluidity buffer.
◉ Fluid Mosaic Model.
Answer: Describes membranes as flexible structures with proteins
floating in a sea of lipids.
◉ Integral proteins.
,Answer: Embedded in membrane (hydrophobic interior).
◉ Transmembrane proteins.
Answer: Span across membrane.
◉ Lipid-anchored proteins.
Answer: Covalently attached to lipids.
◉ Peripheral proteins.
Answer: Loosely attached to membrane surface.
◉ Glycoproteins & Glycolipids.
Answer: On extracellular surface, used for cell recognition and
signaling.
◉ Selective Permeability.
Answer: Allows some molecules to cross while blocking others.
◉ Passive Transport.
Answer: Molecules move down concentration gradient.
◉ Simple Diffusion.
,Answer: Small, nonpolar molecules (e.g., O₂, CO₂).
◉ Facilitated Diffusion.
Answer: Uses proteins.
◉ Osmosis.
Answer: Diffusion of water.
◉ Aquaporins.
Answer: Channel proteins for water.
◉ Osmolarity & Tonicity.
Answer: Isotonic: Equal solute concentration.
◉ Hypertonic solution.
Answer: Higher solute outside; cell shrinks.
◉ Hypotonic solution.
Answer: Lower solute outside; cell swells.
◉ Active Transport.
Answer: Uses ATP; moves molecules against gradient (low → high).
, ◉ Sodium-potassium pump.
Answer: Example of active transport.
◉ Prokaryotes.
Answer: No nucleus.
◉ Eukaryotes.
Answer: Have nucleus and organelles.
◉ Endocytosis.
Answer: Phagocytosis: 'Cell eating' (e.g., engulfing bacteria).
◉ Exocytosis.
Answer: Exports materials (e.g., hormones, neurotransmitters) via
vesicle fusion with membrane.
◉ Triglyceride structure.
Answer: Glycerol backbone + 3 fatty acid tails.
◉ Plant oils vs. animal fats.
Answer: Oils: Unsaturated, liquid. Fats: Saturated, solid.
AND FUNCTION PRACTICE SET ANSWERS
FULL SOLUTION
◉ Cell Theory.
Answer: All living things are made of cells.
◉ Membrane Structure.
Answer: Phospholipid bilayer: Hydrophobic interior, hydrophilic
exterior.
◉ Membrane Fluidity Influencers.
Answer: Temperature: Higher = more fluid.
◉ Cholesterol in membranes.
Answer: Stabilizes membrane; fluidity buffer.
◉ Fluid Mosaic Model.
Answer: Describes membranes as flexible structures with proteins
floating in a sea of lipids.
◉ Integral proteins.
,Answer: Embedded in membrane (hydrophobic interior).
◉ Transmembrane proteins.
Answer: Span across membrane.
◉ Lipid-anchored proteins.
Answer: Covalently attached to lipids.
◉ Peripheral proteins.
Answer: Loosely attached to membrane surface.
◉ Glycoproteins & Glycolipids.
Answer: On extracellular surface, used for cell recognition and
signaling.
◉ Selective Permeability.
Answer: Allows some molecules to cross while blocking others.
◉ Passive Transport.
Answer: Molecules move down concentration gradient.
◉ Simple Diffusion.
,Answer: Small, nonpolar molecules (e.g., O₂, CO₂).
◉ Facilitated Diffusion.
Answer: Uses proteins.
◉ Osmosis.
Answer: Diffusion of water.
◉ Aquaporins.
Answer: Channel proteins for water.
◉ Osmolarity & Tonicity.
Answer: Isotonic: Equal solute concentration.
◉ Hypertonic solution.
Answer: Higher solute outside; cell shrinks.
◉ Hypotonic solution.
Answer: Lower solute outside; cell swells.
◉ Active Transport.
Answer: Uses ATP; moves molecules against gradient (low → high).
, ◉ Sodium-potassium pump.
Answer: Example of active transport.
◉ Prokaryotes.
Answer: No nucleus.
◉ Eukaryotes.
Answer: Have nucleus and organelles.
◉ Endocytosis.
Answer: Phagocytosis: 'Cell eating' (e.g., engulfing bacteria).
◉ Exocytosis.
Answer: Exports materials (e.g., hormones, neurotransmitters) via
vesicle fusion with membrane.
◉ Triglyceride structure.
Answer: Glycerol backbone + 3 fatty acid tails.
◉ Plant oils vs. animal fats.
Answer: Oils: Unsaturated, liquid. Fats: Saturated, solid.
