Diffusion

Question 1

What is diffusion?

Answer 1

The movement of substances from higher to lower concentration until equilibrium is reached

Question 2

What are the two forms of membrane transport?

Answer 2

Passive or active

Question 3

What is a solute?

Answer 3

What is dissolved

Question 4

What is a solvent?

Answer 4

The substance that dissolves the solute

Question 5

What is simple diffusion? (4 points)

Answer 5

• substances move freely between phospholipids
• move from high to low concentration until equilibrium is reached
• move by kinetic energy
• small, lipid-soluble, non-polar substances e.g oxygen, carbon dioxide, alcohol

Question 6

Facilitated diffusion? (4 points)

Answer 6

• mediated by a protein carrier or channel to pass through the membrane
• move from high to low concentration
• move by kinetic energy
• large, non-lipid soluble substances, charged ions e.g glucose, amino acids

Question 7

What are the two types of facilitated diffusion?

Answer 7

• carrier mediated facilitated diffusion (via a carrier protein)
• channel mediated facilitated diffusion (like opening a door)

Question 8

What is osmosis?

Answer 8

Movement of a solvent (water on the body)

Question 9

How does osmosis work? (3 points)

Answer 9

• mediated by a protein channel/directly between phospholipids (aquaporin)
• moves from an area with more water (more dilute) to less water (more concentrated with solutes)
• no ATP required

Question 10

What is low osmolarity?

Answer 10

Low solute concentration

Question 11

What is high osmolarity?

Answer 11

High solute concentration

Question 12

What is primary active transport? (2 points)

Answer 12

• solutes are moved uphill against a concentration gradient
• requires cellular ATP energy to change the shape of a carrier protein and pump the substances across the membrane. E.g sodium/potassium pump

Question 13

What are the two types of active transport?

Answer 13

• primary active transport

- vesicular transport