B1 Active Transport (page 19)

Question 1

What is Active Transport?

Answer 1

Sometimes substances need to be absorbed against a concentration gradient ie. from a lower to a higher concentration. This is Acive Transport.

Question 2

What do Root hairs take in?

Answer 2

Minerals and Water.

Question 3

Explain what happens on plant roots when they grow?

Answer 3

the cells on plant roots grown into hairs, which stick out into the soil.

Question 4

Each branch of the hairs will be covered in millions of what?

Answer 4

microscopic hairs.

Question 5

the millions of microscopic hairs gives the plant a large surface area for absorbing what?

Answer 5

water and mineral ions from the soil.

Question 6

What do Plants need mineral ions for?

Answer 6

for healthy growth.

Question 7

Is the concentration of minerals higher in the root hair cells or in the soil around them?

Answer 7

the concentration of minerals is usually higher in the root hair cells.

Question 8

Can the root hair cells use diffusion to take up minerals from the soil?

Answer 8

No, as the concentration of minerals is the root hair is higher than in the soil.

Question 9

Root Hairs take in minerals using what?

Answer 9

Active Transport.

Question 10

Minerals should move out of the root hairs,how do they do this by?

Answer 10

Then the cells must use another method to draw them in. (active transport)

Question 11

Active transport allow the plant to what?

Answer 11

it allows the plant to absorb minerals from a very dilute solution, against a concentration gradient. This is essential for it’s growth. But active transport needs ENERGY from RESPIRATION to make it work.

Question 12

Active transport also happens in humans, give an example?

Answer 12

taking glucose from the gut and from the kidney tubules.

Question 13

Why do Humans need Active Transport?

Answer 13

to stop us starving.

Question 14

When and where is Active Transport used in humans?

Answer 14

Active transport is used in the gut when there is a lower concentration of nutrients in the gut, but a higher concentration of nutrients in the blood.

Question 15

When there’s a higher concentration of glucose and amino acids in the gut, what happens?

Answer 15

they diffuse naturally into the blood.

Question 16

What happens if there is a lower concentration of nutrients in the gut than there is in the blood?

Answer 16

This means the concentration gradient is the wrong way around, so Active Transport is then used, (the same process used in plant roots is used in humans) (see diagram on page 19).

Question 17

What do Active transport allow in humans?

Answer 17

it allows nutrients to be taken into the blood, despite the fact that the concentration gradient is the wrong way.

This means that glucose can be taken into the bloodstream when it’s concentration in the blood is already higher than in the gut. It can then be transported to cells where it’s used for respiration (see page 54).

Question 18

What is the important difference between active transport and diffusion?

Answer 18

Active transport uses energy. (imagine a pen of sheep in a field. If you open the pen, the sheep will happily diffuse from the area of higher sheep concentration into the field, which has a lower sheep concentration - you won’t have to do a thing. - To get them back in the pen though, you’ll have to put in quite a bit of energy).

Question 19

What is the purpose of active transport in the gut? (1 mark).

Answer 19

Active transport allows nutrients such as glucose to move from a lower concentration in the gut to a higher concentration in the blood (against te cocentration gradient) 1 mark