SB6 - Plants

Question 1

What are companion cells and what do they do?

Answer 1

Actively pump sucrose into and out of the sieve cells that form the sieve tubes and contain many mitochondria to do this

Question 2

What is transpiration?

Answer 2

The flow of water into the roots, up the xylem and out of the leaves in a one way movement

Question 3

What is translocation?

Answer 3

The movement of sucrose through the phloem of a plant in a two way movement

Question 4

What factors affect the rate of transpiration?

Answer 4

1. Light intensity - increases transpiration through stomata widening
2. Humidity - decreases transpiration as more water around the leaf affects the concentration gradient
3. Temperature - increases transpiration as there is more evaporation
4. Wind - increases transpiration as water is moved away from the stomata quicker

Question 5

How are root hair cells adapted for their jobs?

Answer 5

They have a large surface area and thin cell walls

Question 6

What are sieve cells?

Answer 6

In the phloem, they transport sucrose in translocation and no mu lease means there is little cytoplasm to make room for the sucrose

Question 7

What is endothermic?

Answer 7

A reaction that takes in energy

Question 8

Why is photosynthesis endothermic?

Answer 8

Takes in light energy so products of the reaction have more energy than the reactants

Question 9

What is glucose for in a plant?

Answer 9

Respiration

Question 10

What is starch used for in a plant?

Answer 10

Stored in them and can be broken down into sucrose

Question 11

What is sucrose for?

Answer 11

A soluble sugar that is transported through the phloem

Question 12

What would happen to light intensity if you doubled the distance from the light?

Answer 12

The light intensity would halve

Question 13

How could you measure light intensity instead of calculating it? [1]

Answer 13

By using a light meter

Question 14

Why would you place a plastic bag over a plant pot in experiment that measures water loss? [2]

Answer 14

To prevent evaporation from water in the soil and to ensure the method is a fair test

Question 15

Why would glucose production be affected if a plant lost a lot of water? [2]

Answer 15

it would decrease as photosynthesis would decrease due to the less water

Question 16

What process moves water from the soil to a plant? [2]

Answer 16

Osmosis as it goes through a partially permeable membrane

Question 17

How would salt solution affect the movement of water into and out of a plant? [2]

Answer 17

Movement of water in would slow as there is less water outside the plant than inside

Question 18

Through what process does carbon dioxide move into the leaves through the stomata?

Answer 18

Diffusion

Question 19

What changes affect the guard cells on a warm day to help the plant survive?

Answer 19

The guard cells will close the stomata to reduce water loss

Question 20

How does carbon dioxide enter a leaf?

Answer 20

Through diffusion as it goes from an area of high concentration to low concentration

Question 21

Describe the process that takes place in a leaf to produce oxygen [3]

Answer 21

Photosynthesis which requires carbon dioxide and water to produce oxygen and glucose
(Qs asks to describe so no explanation is needed)

Question 22

How do auxins cause the shoot of a plant to grow towards the light? [2]

Answer 22

The auxins move to the shaded side of the shoot causing the cells in that side to elongate