Gas And Solute Exchange

Question 1

Name 3 ways substances move?

Answer 1

Substances move by diffusion, osmosis and active transport.

Question 2

What needs to get into plant cells in order for photosynthesis to happen?

Answer 2

Carbon dioxide and water need to

Question 3

What has to enter cells in order for respiration to happen?

Answer 3

Glucose and oxygen both have to get inside the cells for respiration to happen.

Question 4

Why do waste materials have to move out of plants?

Answer 4

So the organism can get rid of them.

Question 5

Define diffusion?

Answer 5

Diffusion is the movement of particles from an area of high concentration to a low concentration.

Question 6

True or false gases can diffuse in and out of cells through cell membranes?

Answer 6

True.

Question 7

What do the exchange surfaces have to allow enough of to pass through them?

Answer 7

They have to allow enough necessary substances to pass through them.

Question 8

Why are exchange surfaces adapted?

Answer 8

In order to maximise effectiveness.

Question 9

Name 4 ways exchange surfaces are adapted and why this maximises effectiveness?

Answer 9

1. They are thin - this is so substance only have a short distance to diffuse.
2. They have a large surface area - this is so lots of substances can diffuse at once.
3. In animals the exchange surface had lots of blood vessels - to get stuff into and out of the blood quickly.
4. In animals there is gas exchange surfaces - this allows air to move in and out.

Question 10

True or false exchanging substances gets more difficult the bigger and more complex the organism is?

Answer 10

True

Question 11

Why does exchanging substances get more harder for bigger and more complex organisms?

Answer 11

Because the place where the substances are needed is further away from the exchange surface.

Question 12

What does the structure of the leaf allow gases to do?

Answer 12

It allows them to diffuse in and out of cells.

Question 13

Where does carbon dioxide diffuse?

Answer 13

Carbon dioxide diffuses into the air spaces within the leaf, then it diffuses into the cells where photosynthesis happens.

Question 14

Where is the exchange surface found on a leaf?

Answer 14

Underneath of the leaf.

Question 15

What is the underside of the leaf covered with?

Answer 15

Tiny holes called stomata which the carbon dioxide diffuses in through.

Question 16

What diffuses out of the stomata?

Answer 16

Oxygen and water vapour diffuse out of the stomata?

Question 17

What is the size of the stomata controlled by?

Answer 17

Guard cells.

Question 18

What happens when the plant is losing water faster then it’s being replaced by the roots?

Answer 18

The guard cells close the stomata if too much water is being lost.

Question 19

Why is closing the stomata helpful to the plant?

Answer 19

By closing the stomata it prevents water vapour diffusing out of the stomata. So this preserves water for the plant and stops the plant wilting.

Question 20

Why does having a flattened shape make the exchange surface on a leaf more effective?

Answer 20

Because having a flattened shape increases the area of the exchange surface so more gases can diffuse into and out of the leaf.

Question 21

Name two exchange surfaces in a plant?

Answer 21

The underneath of a leaf and the walls of cells inside the leaf.

Question 22

What does the air spaces inside the leaf maximise?

Answer 22

The air spaces increase the area of the exchange surface so there’s more chance for carbon dioxide to get into cells.

Question 23

True or false water vapour evaporates from the cells inside the leaf?

Answer 23

True.

Question 24

How does the water vapour move from the inside the leaf into the air?

Answer 24

Once the water vapour has evaporated from the cells in the leaf then it escapes by diffusion because there’s a lot of it inside the leaf and less of it in the air outside.

Question 25

Name 3 conditions where evaporation happens the quickest?

Answer 25

In hot, dry and windy conditions.