Bio 2: Cell Transport

Question 1

What is diffusion?

Answer 1

Net movement of particles from an area of high concentration to an area of low concentration along a concentration gradient- this is a passive process
(Does not require energy from respiration)

Question 2

Name three factors that affects the rate of diffusion

Answer 2

Concentration gradient, temperature, membrane surface area

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 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 a dilute solution to a concentrated solution 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 a dilute solution to a more concentrated solution- using energy from 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