B5: Plant nutrition

Question 1

Function of chlorophyll

Answer 1

1. Green pigment => makes the leaf look green
2. It’s kept inside the chloroplast
3. Chlorophyll absorbs the energy sunlight provided - releases the energy to make CO2 combine with water
   (light energy is transferred to chemical energy)

Question 2

The function of epidermis cells

Answer 2

1. Do not contain any chloroplasts + transparent => The mesophyll layer could absorb sunlight
2. Protect the inner layers’ cell

Question 3

The function of waxy cuticle

Answer 3

1. Prevent water loss from the leaf

2. Transparent

Question 4

The function of stomata and guard cell

Answer 4

Stomata - a small hole that enables gas exchange for the leaf

Guard cell - A pair of sausage-shaped, which can open or close the hole

Question 5

What does the middle of the leaf’s layer call

Answer 5

The mesophyll layer

Question 6

The function of the palisade mesophyll

Answer 6

• Chloroplasts are more compact to each other and arranged like a fence

Question 7

The function of the spongy mesophyll

Answer 7

• Cells are rounder and arranged quite loosely, with large air space between

Question 8

the function of vascular bundles

Answer 8

• Xylem: thick-walled and carrying water to cells from the leaf
• Phloem: thin-walled and carrying away sucrose and other substances that the leaf has made.

Question 9

Leaf’s adaptation to absorb the most carbon dioxide

Answer 9

• The leaf is held out into the air by the stem and leaf stalk
• Large surface area

Question 10

The great journey of carbon dioxide

Answer 10

• Carbon dioxide can get into the leaf through the stomata, which can be done by diffusion
  + Behind each stoma is a chain of air space which is between the spongy mesophyll cells.
  => Carbon dioxide can diffuse to all cells in the leaf

Question 11

The great journey of water

Answer 11

• Water is obtained from the soil

- It is then absorbed by the root hairs -> carried up to the mesophyll inside the xylem vessels by osmosis

Question 12

Leaf’s adaptation to absorb sunlight efficiently

Answer 12

• Broad surface area
• Its position so it can’t interrupt other leaves to also obtain sunlight
• Thinness of the leaf
• Chloroplasts are arranged in a particular order so it could absorb sunlight as much as possible

Question 13

How does glucose use for energy

Answer 13

Glucose provides the energy needed for respiration in cells

Question 14

Why glucose is not good for storage

Answer 14

1. highly reactive - disrupt other reactions in the cell

2. Soluble - affect the concentration of the cell -> affect osmosis

Question 15

Why starch is good for storage

Answer 15

1. Insoluble

2. Not very reactive

Question 16

How does glucose use for making other substances

Answer 16

1. Glucose can be combined together to make other carbohydrates (e.g sucrose + starch)
2. Glucose can combine with mineral ions in the soil
   - Glucose + nitrate ions -> amino acids, which can be used for making proteins
   - Glucose + magnesium -> make chlorophyll

Question 17

where does photosynthesis take place?

Answer 17

chloroplast