2(e) Human Nutrition

Question 1

2.18

Understand the process of photosynthesis and its importance in the conversion of
light energy to chemical energy

Answer 1

Fill this in

Question 2

2.19

Know the word equation and the balanced chemical symbol equation for
photosynthesis

Answer 2

Carbon dioxide + water -> Glucose + Oxygen
6CO2 + 6H2O -> C6H12O6 + 6O2

Question 3

2.20

Understand how varying carbon dioxide concentration, light intensity and temperature
affect the rate of photosynthesis

Answer 3

More CO2 concentration, light intensity both each increase the rate of photosynthesis. If the temperature is at the optimum temp it will also increase the rate of photosynthesis. If the temperature is too high or low the rate will decrease.

Question 4

2.21

Describe the structure of the leaf and explain how it is adapted for photosynthesis

Answer 4

Cuticle - Prevents water loss by evaporation
Upper Epidermis - Transparent to allow the maximum amount of light to enter the chlorplast in the palisade cells
Lower Epidermis - Contain guard cells and stomata
Stomata - Allow carbon dioxide to diffuse into the leaf
Guard cells - Change shape to open and close stoma
Palisade mesosphyll cells - Main site of photosynthesis
Air space in between mesosphyl cells - Main gas exchange surface of leaf. Absorbs Carbon Dioxide and releasing Oxygen and Water vapour. Airspace let gas in spongy mesophyll to diffuse in
Xylem - Water and mineral ions are supplied to the leaf by Xylem
Phloem - Supplies all other parts of the plant, so that tissues and organs that cant make their own food receive products of photosynthesis

Question 5

2.22

Understand that plants require ……. ions for ……, and that ……… ions are
needed for ……….. and …….. ions are needed for …… acids

Answer 5

1. mineral
2. growth
3. magnesium
4. chlorophyll
5. nitrate
6. amino

Question 6

2.23

Investigate photosynthesis, showing the evolution of oxygen from a water
plant, the production of starch and the requirements of light, carbon dioxide and
chlorophyll

Practical

Question 7

Understand that a balanced diet should include appropriate portions of

Answer 7

Carbohydrate, protein, lipid, vitamins, minerals, water and dietary fibre.

Question 8

Identify the sources and describe the functions of carbohydrates, protein, lipid, vitamins A, C and D, the mineral ions calcium and iron, water and dietary fibre as components of the diet.

Answer 8

Carbohydrates: Source of energy
Protein: Growth and maintenance
Lipids: Provide energy for muscles and body processes.