U3 KA1

Question 1

What is food security?

Answer 1

• the ability of human populations to have access to food of sufficient quality and quantity.

Question 2

What is 1 global concern for food security?

Answer 2

• rapidly increasing global population, and increasing demand for food production.

Question 3

How is food production increased? (3)

Answer 3

• through the breeding of higher breed cultivators.
• use of fertilisers.
• protection of crops from pests and diseases.

Question 4

What are the limiting factors of agricultural production? (5)

Answer 4

• soil moisture, temperature, light availability, nutrient availability, pests.

Question 5

How can agriculture production be improved? (3)

Answer 5

• using pesticides and fertilisers.
• breeding higher yield cultivars.
• crop protection.

Question 6

What is a trophic level?

Answer 6

• an organisms place on the food web.
• eg. producer, primary consumer, etc.

Question 7

Why are crops grown instead livestock?

Answer 7

• growing crops is more efficient, as over 90% of energy is lost between trophic levels.

Question 8

Why is livestock produced instead of crops?

Answer 8

• livestock production is possible in areas that plants cannot grow.

Question 9

What is photosynthesis?

Answer 9

• the process by which green plants take energy from sunlight, converting it to sugar.

Question 10

What is chlorophyll A?

Answer 10

• the main pigment found in chloroplasts of plants that absorb light energy.

Question 11

What is the role of chlorophyll B and carotenoids?

Answer 11

• to absorb light from other wavelengths, passing the energy to chlorophyll A.
• this allows the chloroplast to extend the range of absorbed wavelengths.

Question 12

What happens to the light that is not absorbed by the plant? (2)

Answer 12

• reflected off the leaf.
• transmitted through the leaf.

Question 13

What happens in stage 1 of Photosynthesis? (2)

Answer 13

• light is absorbed by pigments, exciting electrons.
• electrons are transferred through ETC, releasing energy used for Photolysis.

Question 14

What happens in Photolysis?

Answer 14

• energy from ETC is used to split water into hydrogen and oxygen.
• hydrogen ions react with NADP to form NADPH.

Question 15

What happens in carbon fixation?

Answer 15

• Co2 is combined with RuBP by the enzyme RuBisCO, to form 3PG.
• ATP phosphorylates 3PG, which combines with the hydrogen ions from NADPH, to form G3P.

Question 16

What are the uses of G3P? (2)

Answer 16

• regeneration of RuBP.
• synthesis of glucose.

Question 17

What are the uses of glucose? (3)

Answer 17

• used as a respiratory substance.
• converted to starch.
• passed to biosynthetic pathways to form DNA, protein and fat.

Question 18

Why does the concentration of RuBP increase, when Co2 concentration decreases? (2)

Answer 18

• there is less Co2 to combine with RuBP.
• 3PG is still regenerated to RuBP so it increases.

Question 19

Why is algae immobilised into gel beads?

Answer 19

• is allows the algae and incubator to be separated easily.