Questions on Diffusion, with answers
20 multiple choice questions on Diffusion, with answers at the end.
Multiple Choice Questions: Diffusion
1. What is diffusion?
A) Movement of molecules from low to high concentration
B) Movement of molecules from high to low concentration
C) Movement of molecules using energy
D) Movement of water across a membrane
2. Diffusion occurs because molecules:
A) Use energy to move
B) Move randomly and spread out
C) Are actively transported
D) Are pushed by the cell
3. Which of the following best describes the direction of diffusion?
A) Against the concentration gradient
B) Along the concentration gradient
C) Random direction only
D) Only through protein channels
4. Diffusion continues until:
A) All molecules are on one side
B) Equilibrium is reached
C) Energy is supplied
D) Molecules stop moving
5. Which of these molecules can easily diffuse through a cell membrane?
A) Large proteins
B) Ions
C) Small nonpolar molecules like oxygen
D) Glucose
6. Diffusion through a membrane without assistance is called:
A) Active transport
B) Facilitated diffusion
C) Simple diffusion
D) Osmosis
7. Facilitated diffusion differs from simple diffusion because it:
A) Requires energy
B) Uses protein channels or carriers
C) Moves molecules from low to high concentration
D) Only transports water
8. Which factor does NOT affect the rate of diffusion?
A) Temperature
B) Concentration gradient
C) Pressure
D) Color of molecules
9. What happens to the rate of diffusion when temperature increases?
A) Rate decreases
B) Rate increases
C) Rate stays the same
D) Diffusion stops
10. In diffusion, molecules move:
A) Only in liquids
B) From an area of higher concentration to lower concentration
C) Only through membranes
D) Against the concentration gradient
11. Which of these is an example of diffusion?
A) Oxygen entering lungs
B) Water moving into a plant cell
C) Protein synthesis
D) Active transport of ions
12. Diffusion is a type of:
A) Passive transport
B) Active transport
C) Endocytosis
D) Exocytosis
13. Which organelle in cells uses diffusion to exchange gases?
A) Mitochondria
B) Ribosome
C) Cell membrane
D) Nucleus
14. Diffusion does NOT require:
A) Concentration gradient
B) Energy input
C) Molecule movement
D) A medium (solid, liquid, or gas)
15. Which of these substances would diffuse most rapidly across a membrane?
A) Large polar molecules
B) Small nonpolar molecules
C) Charged ions
D) Proteins
16. Diffusion is fastest when the concentration gradient is:
A) Steep
B) Shallow
C) Non-existent
D) Reversed
17. Which of the following is NOT true about diffusion?
A) It is a spontaneous process
B) It requires ATP
C) It results in even distribution of molecules
D) It depends on random molecular motion
18. Which statement is true about facilitated diffusion?
A) It requires energy
B) It moves substances against the gradient
C) It uses membrane proteins to help molecules cross
D) It is faster than simple diffusion for all molecules
19. What is a concentration gradient?
A) Difference in molecule concentration between two regions
B) The energy used to move molecules
C) The membrane proteins that assist diffusion
D) The thickness of a membrane
20. Diffusion can occur in:
A) Only gases
B) Only liquids
C) Gases, liquids, and solids
D) Only across membranes
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Answer Key
1. B) Movement of molecules from high to low concentration
2. B) Move randomly and spread out
3. B) Along the concentration gradient
4. B) Equilibrium is reached
5. C) Small nonpolar molecules like oxygen
6. C) Simple diffusion
7. B) Uses protein channels or carriers
8. D) Color of molecules
9. B) Rate increases
10. B) From an area of higher concentration to lower concentration
11. A) Oxygen entering lungs
12. A) Passive transport
13. C) Cell membrane
14. B) Energy input
15. B) Small nonpolar molecules
16. A) Steep
17. B) It requires ATP
18. C) It uses membrane proteins to help molecules cross
19. A) Difference in molecule concentration between two regions
20. C) Gases, liquids, and solids
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