Transport in Cells

Question 1

Diffusion-

(definition)

Answer 1

the spreading out of particles from an area of higher concentration to an area of lower concentration

Question 2

Only very _____ molecules (e.g ______ and _______) can _______ through cell membranes

Answer 2

Only very small molecules (e.g oxygen and glucose) can diffuse through cell membranes

Question 3

What three factors increase the rate of diffusion across a cell membrane?

Answer 3

• a high concentration gradient (e.g loads of he particles on one side and hardly any on the other)
• a high temperature
• a large surface area

Question 4

Osmosis-

(definition)

Answer 4

the movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration

Question 5

Active transport-

(definition)

Answer 5

the movement of a substance against the concentration gradient. Unlike diffusion and osmosis, it requires energy from respiration.

Question 6

What does Active Transport allow?

Answer 6

• mineral ions (for plant growth) to be absorbed from the soil into root hair cells
• glucose (for cell respiration) to be absorbed into the bloodstream from the gut