B2- cell transport

Question 1

What is diffusion

Answer 1

The movement of particles from areas of high concentration to areas of low concentration along a concentration gradient

Question 2

Name 3 factors that affect the rate of diffusion

Answer 2

Concentration gradient, temperature, surface area of the membrane

Question 3

How are Villi adapted for exchanging substances

Answer 3

Long and thin- increases surface area
one-cell-thick membrane - short diffusion pathway
good blood supply - maintains a steep concentration gradient

Question 4

How are the lungs adapted for efficient gas exchange

Answer 4

alveoli - large surface area
moist membranes - increases rate of diffusion
one-cell-thick membranes - short diffusion pathway
good blood supply - maintains a steep concentration gradient

Question 5

How are fish gills adapted for efficient gas exchange

Answer 5

large surface area for gases to diffuse across
thin layer of cells - short diffusion pathway
good blood supply - maintains a steep concentration gradient

Question 6

What is osmosis

Answer 6

diffusion of water from an area of high concentration to an area of low concentration through a partially permeable membrane

Question 7

Give one example of osmosis in a plant

Answer 7

Water moves from the soil into the root hair cell

Question 8

What is active transport

Answer 8

movement of particles against a concentration gradient from an area of high concentration to a low concentration. This requires energy and respiration

Question 9

Why is active transport needed in plant roots

Answer 9

concentration of mineral ions in the soil is lower than inside the root hair cells - the mineral ions must move against the concentration gradient to enter the root hair cells

Question 10

What is the purpose of active transport in the small intestine

Answer 10

Sugars can be absorbed when the concentration of sugar in the small intestine is lower than the concentration of sugar in the blood