Question

a cell uses many methods to transport solutes across the plasma membrane. classify the descriptions as either simple diffusion, facilitated diffusion, or active transport.

simple diffusion\tfacilitated diffusion\tactive transport

answer bank
movement of solutes into the cell directly through the plasma membrane
movement of solutes into the cell down their concentration gradient using membrane proteins

Explanation:

To solve this, we analyze each transport mechanism:

Simple Diffusion:

• Definition: Movement of solutes directly through the plasma membrane (no protein help), down concentration gradient (high → low), no energy.
• Match: "movement of solutes into the cell directly through the plasma membrane"

Facilitated Diffusion:

• Definition: Movement of solutes down concentration gradient (high → low) using membrane proteins (channels or carriers), no energy.
• Match: "movement of solutes into the cell down their concentration gradient using membrane proteins"

Active Transport:

• Definition: Movement of solutes against concentration gradient (low → high) using membrane proteins, requires energy (ATP). Since the answer bank isn’t fully visible, but typical examples include “movement of solutes against concentration gradient” or “requires energy/ATP.”

Final Classification:

• Simple diffusion: movement of solutes into the cell directly through the plasma membrane
• Facilitated diffusion: movement of solutes into the cell down their concentration gradient using membrane proteins
• Active transport: (depends on remaining answer bank options, e.g., “requires energy,” “against gradient,” etc.)

(Note: If the answer bank had a third option like “requires ATP” or “moves against concentration gradient,” it would go to Active Transport.)

Answer:

To solve this, we analyze each transport mechanism:

Simple Diffusion:

• Definition: Movement of solutes directly through the plasma membrane (no protein help), down concentration gradient (high → low), no energy.
• Match: "movement of solutes into the cell directly through the plasma membrane"

Facilitated Diffusion:

• Definition: Movement of solutes down concentration gradient (high → low) using membrane proteins (channels or carriers), no energy.
• Match: "movement of solutes into the cell down their concentration gradient using membrane proteins"

Active Transport:

• Definition: Movement of solutes against concentration gradient (low → high) using membrane proteins, requires energy (ATP). Since the answer bank isn’t fully visible, but typical examples include “movement of solutes against concentration gradient” or “requires energy/ATP.”

Final Classification:

• Simple diffusion: movement of solutes into the cell directly through the plasma membrane
• Facilitated diffusion: movement of solutes into the cell down their concentration gradient using membrane proteins
• Active transport: (depends on remaining answer bank options, e.g., “requires energy,” “against gradient,” etc.)

(Note: If the answer bank had a third option like “requires ATP” or “moves against concentration gradient,” it would go to Active Transport.)