3.1 Criteria

Question 1

State what is meant by food security:

Answer 1

Enabling human populations to access food of sufficient quality and quantity

Question 2

As the human population increases, what happens to the demand for food production?

Answer 2

Increases

Question 3

What is food production dependent on?

Answer 3

Photosynthesis

Question 4

Name 4 examples of plant crops?

Answer 4

Cereals, potato, roots and legumes

Question 5

What is the limiting factor on crop production?

Answer 5

Area available

Question 6

What 4 factors does food production depend on?

Answer 6

1. breeding of higher yielding cultivars
2. use of fertiliser
3. protecting crops from pests and diseases
4. competition

Question 7

Breeders develop crops that have what (4)?

Answer 7

1 Higher nutritional values
2. Resistance to pests and diseases
3. physical characteristics suited to rearing and harvesting
4. phenotypes able to thrive in particular environmental conditions

Question 8

Why do livestock produce less food per unit area that crop plants?

Answer 8

Due to the loss of energy between trophic levels

Question 9

Give the summary equation for photosynthesis:

Answer 9

Carbon Dioxide+water->light +chlorophyll -> oxygen+glucose

Question 10

What happens in the light dependent stage of photosynthesis?

Answer 10

Light energy is absorbed by photosynthetic pigments to generate ATP and for photolysis.

Question 11

When light energy is not absorbed what is its two other fates?

Answer 11

Transmitted or reflected

Question 12

Name the principal photosynthetic pigment

Answer 12

Chlorophyll a

Question 13

Name the two accessory photosynthetic pigments

Answer 13

Chlorophyll b and carotenoids

Question 14

Each pigment can absorb a different range of what?

Answer 14

Wavelengths of light

Question 15

What do accessory pigments do?

Answer 15

Extend the range of wavelength absorption and pass energy to chlorophyll a

Question 16

What does the absorption spectrum show?

Answer 16

The wavelength of light absorbed by individual pigments

Question 17

What does an action spectrum show?

Answer 17

The rate of photosynthesis when specific wavelengths of light are supplied to photosynthetic pigments

Question 18

What does absorbed light do to an electron molecule?

Answer 18

Excites the electron

Question 19

Excited electrons are passed through what?

Answer 19

The electron transport chain- releasing energy to generate ATP by ATP synthase

Question 20

Absorbed light is also used for what else?

Answer 20

For photolysis in which water is split into oxygen and hydrogen

Question 21

Oxygen from photolysis is what?

Answer 21

Evolved

Question 22

Hydrogen from photolysis is transferred to what?

Answer 22

The coenzyme NADP

Question 23

The carbon fixation stage of photosynthesis is called?

Answer 23

The Calvin Cycle

Question 24

What is the function of the enzyme RuBisCo?

Answer 24

Fixes carbon dioxide by attaching it to ribulose bisphosphate (RbBP) to form 3-phowphoglycerate (3PG)

Question 25

3PG is phosphorylated by ATP and combined with hydrogen from NADPH to from what?

Answer 25

Glyceraldehyde - 3 -
phosphate (G3P)

Question 26

G3P is used to regenerate what?

Answer 26

RuBP for the synthesis of glucose

Question 27

What are the 4 fates of glucose?

Answer 27

1. Used as a respiratory substrate
2. Synthesised into starch (storage carbohydrate)
3. Synthesised into cellulose (structural carbohydrate)
4. Passed to biosynthetic pathways to form DNA, protein and fat