Leaves

Question 1

Define photosynthesis

Answer 1

It is the process in which plants manufacture carbohydrates (sugar) from raw materials ( water, carbon dioxide) using energy from light

Question 2

Define chlorophyll

Answer 2

They are found in chloroplast and they are the green pigment found in leaves that trap in light to convert into chemical energy which is used to make food for the plant ( glucose)

Question 3

Define guard cells

Answer 3

They are epidermal cells that control gas diffusion by regulating the opening and closure of stomal pores.

Question 4

2.Describe the function of the leaf & which organelle help it carry out that function?

Answer 4

Carry out photosynthesis to give out oxygen ( by product) and make glucose (main product) and chloroplast ( which contain chlorophyll) helps it carry out.

Question 5

Note down as many ways as you can that leaves are adapted for photosynthesis

Answer 5

1- Large surface area to maximise light absorption.

2- Green- Contains chlorophyll which traps in light and uses the energy from it to carry out photosynthesis.

3- Stomata to help the diffusion of gases in and out.

4- Network of veins ( vascular bundle) to help transportation of water ( xylem) and sugar (phloem).

5- Thin to help gases diffuse in and out of the leaf easily

6- Waxy layer at the top of the leaf to reduce/ minimise water loss.

Question 6

Write down what you would find in a leaf ( 9 marks)

Answer 6

1- Wax cuticle
2- Upper epidermis
3- Lower epidermis
4- Mesophyll:
5- Palisade mesophyll ( contains chloroplast )
6- Spongy mesophyll ( vasuclar bundle: xylem and phloem)
7- air spaces
8-Guard cells with chloroplast
9- Stomata

Question 7

How is the Palisade layer different to the spongy layer?

Answer 7

Palisade contains chlorophyll however spongy conatins vascular bundel ( xylem and phloem

Question 8

2. What’s the function of the Stomata?

Answer 8

Gas exchange: Allows gases to diffuse in and out of the cell

Question 9

1. What stops the leaf losing water on the top surface?

Answer 9

Wax cuticle

Question 10

2. Where does photosynthesis occur?

Answer 10

Palisade mesophyll

Question 11

Which part of the leaf lets the Carbon Dioxide in and the Oxygen out?

Answer 11

Stomata

Question 12

What do the air spaces do?

Answer 12

Store gases

Question 13

Why does the stomata close at night?

Answer 13

No light, no photosynthesis, no exchange of gases.

Question 14

Why does a leaf need a large surface area?

Answer 14

Maximise absorption of light

Question 15

Why do the leaves on cacti found in the desert have waxy coatings?

Answer 15

To minimise water loss in an extremely hot climate

Question 16

How is palisade mesophyll adapted to maximise photosynthesis

Answer 16

1- Large vacuole which ensure that the chloroplast is at the edge of the cell

2- Lots of chlorophyll

3- At the top of the leaf which allows more light to be absorbed

4- cells are tightly packed together

Question 17

Function Guard cells

Answer 17

Open the stomal pores during the day and close it during the night .

Question 18

Function of stomata

Answer 18

Tiny pores at the bottom the leaf that allow gas diffusion

Question 19

Why do you think there’s a high concentration of chloroplasts within the palisade layer in Leave? Explain?

Answer 19

Because the palisade layer is at the top of the leaf so there is a high concentration to allow for more light absorption.

Question 20

Identify how each reactant gets into the palisade cell: ( 3 marks)
Carbon dioxide:

Water:

Sunlight:

Answer 20

Carbon dioxide: through stomata

Water: absorbed through the roots and travels up through the xylem

Sunlight: absorbed by chlorophyll in the chloroplast

Question 21

Explain the adaptation of root hair cell

Answer 21

Hair like projection to increase surface area to absorb more water

Question 22

Explain why a large surface area is important

Answer 22

Maximise light absorption

Question 23

Explain why having many stomata is important

Answer 23

To allow for gas exchange

Question 24

Explain why a leaf being thin is important

Answer 24

Allow gases to diffuse in and out of the leaf easily

Question 24

Explain why a leaf can change direction is important

Answer 24

Face the sunlight

Question 25

Explain why a chloroplast is important

Answer 25

Contains chlorophyll which traps light energy from the sun which is needed for photosynthesis

Question 26

Explain why a waxy layer is important

Answer 26

Reduce water loss

Question 27

Explain why veins is important

Answer 27

Transport of water (xylem) to the leaf and glucose ( phloem) away from the leaf to the rest of the plant