3.1 Food Supply, Plant Growth and Productivity

Question 1

Food security

Answer 1

Ability of human populations to access food of sufficient quality and quantity

Question 2

Production

Answer 2

Must be sustainable and not degrade natural resources that agriculture needs

Agricultural system shouldn’t deplete nutrients in soil, reduce biodiversity or pollute environment

Question 3

Factors controlling plant growth

Answer 3

Breeding higher yielding cultivators

Decreasing competition

Appropriate soil nutrients

Question 4

Selective breeding

Answer 4

Male and females selected to breed if they have desirable qualities breeders want

Question 5

Desirable characteristics for crops

Answer 5

Higher nutritional values

Quick growth

High crop yield

Question 6

Desirable characteristics for livestock

Answer 6

Higher nutritional values

Quick growth

Resistant to disease

Question 7

Agricultural produce

Answer 7

All food production (even livestock) is dependant on photosynthesis

Plant crop examples- cereals, potatoes, legumes, roots

Question 8

Crops vs livestock

Answer 8

Livestock produce less food peer unit area than crop plants (energy lost through trophic levels)

Livestock production may be possible in habitats unsuitable for crop growth

Question 9

Photosynthetic pigments

Answer 9

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

Light energy that isn’t absorbed is transmitted or reflected

Green leaves contain: chlorophyll a, chlorophyll b, carotenoids

Each pigment absorbs different range of wavelengths of light, allows photosynthesis to take place over wider range of wavelength

Chlorophyll a absorbs mostly blue light, chlorophyll b absorbs mostly red light

Green light reflected or transmitted by leaf giving it green colour

Question 10

Absorption spectrum

Answer 10

Shows absorption of each photosynthetic pigment at different wavelength of light

Question 11

Action spectrum

Answer 11

Shows rate of photosynthesis at each wavelength of light by the plant

Question 12

Chloroplast

Answer 12

Lamellae- links all grana together

Stoma- site of carbon fixation, no chlorophyll

Granum- site of light dependent stage, chlorophyll

Question 13

Stage 1- The light reactions

Answer 13

Light energy from sun absorbed by photosynthetic pigments

Absorbed light energy excite electrons in pigment molecule

Transfer of electrons through ETC releases energy to generate ATP by ATP synthase

Energy used to generate ATP and split water into hydrogen and oxygen