Food supply and Plant productivity 3.1

Question 1

What is food security?

Answer 1

The ability of human populations to access food of sufficient quality in sufficient quantity.

Question 2

What can using pesticides, fertilisers and intensive farming methods often lead to?

Answer 2

Environmental Degradation

Question 3

What factors effect food production?

Answer 3

Breeding higher yielding cultivars
Pests
Soil nutrients
Soil profile
Diseases
Competition

Question 4

Ways to improve crop yields?

Answer 4

Reducing competition by adding nutrients to soil and remove factors limiting plant growth
Replacing existing strains of crops with higher yielding cultivar
Protecting crops from pests, diseases and competition by using pesticides etc
developing pest-resistant crops

Question 5

How is energy lost between trophic levels in food chains?

Answer 5

Undirected food and waste, movement and maintaining body temperature.

Question 6

Shorter food chains have much ____ loss of energy

Answer 6

Less

Question 7

Land unsuitable for crop growth can be used for?

Answer 7

Livestock

Question 8

What is light?

Answer 8

A form of electromagnetic radiation which travels in waves

Question 9

The wavelength is between _____

Answer 9

Two crests on a wave

Question 10

Wavelength is measured in

Answer 10

Nanometres (nm)

Question 11

When light comes into contact with a substance it can be?

Answer 11

Absorbed, Reflected or Transmitted

Question 12

The spectrum of visible light can be seen using a

Answer 12

Spectroscope

Question 13

What colours do chlorophyll a and b absorb?

Answer 13

Red and Blue

Question 14

What are the accessory pigments?

Answer 14

Carotenoids

Carotene and Xanthophyll

Question 15

What do accessory pigments do?

Answer 15

They extend the wavelengths of light absorbed by pigments and pass the energy on to chlorophyll for use in photosynthesis.

Question 16

What is the ABSORPTION spectrum?

Answer 16

A graph which shows the wavelengths of light absorbed by each pigments.

Question 17

What is the ACTION spectrum?

Answer 17

A graph which shows the rate of photosynthesis at different wavelengths of light.

Question 18

What does the absorbed light do first?

Answer 18

It excites electrons in the pigment molecule.

Question 19

What happens in the light dependant stage (Photolysis)

Answer 19

The electrons are captured by the primary electron acceptor and transferred along an electron transport chain.

Question 20

What does the transfer of high energy electrons do?

Answer 20

Releases energy to generate ATP by the enzyme ATP synthase. This is known as photophosphorylation

Question 21

What happens in photolysis?

Answer 21

Water is split. The evolved oxygen is released as a by-product. Hydrogen is transferred to the coenzyme NADP and then transferred to the next stage.

Question 22

The Carbon FIxation stage is?

Answer 22

A series of enzyme controlled reactions

Question 23

What does RuBisCO do?

Answer 23

Fixes to CO2 from the atmosphere by attaching it to RuBP to form 3PG

Question 24

What does RuBisCO stand for?

Answer 24

Ribulose Biophosphate Carboxylase Oxygenase

Question 25

What does RuBP stand for?

Answer 25

Ribulose Biphosphate

Question 26

What does 3PG stand for?

Answer 26

3-phosphoglycerate

Question 27

What happens to 3PG and what does it form?

Answer 27

It is phosphorylase’s by ATP and combined with NADPH to form G3P

Question 28

What does G3P stand for?

Answer 28

Glyceraldehyde-3-phosphate

Question 29

What does G3P do?

Answer 29

It is used to regenerate RuBP and for the synthesis of glucose

Question 30

What are the uses of glucose?

Answer 30

Respiratory substrate
Starch
Cellulose 
Fats
Nuclei acids
Protein