3.1 Food Supply, Plant Growth and Productivity Flashcards

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1
Q

Define ‘Food Security’

A

The ability of a population to access food of sufficient quality and quantity

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2
Q

What are the three factors that influence food security?

A
  • Food Quantity
  • Food Quality
  • Food Access
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3
Q

Why is food security becoming harder to achieve?

A

Due to the increasing rate of population growth and lack of available land to grow food

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4
Q

What does food availability depend on?

A

Sustainable Agricultural Methods

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5
Q

What does ‘Sustainable’ mean in relation to plant growth

A

Sustainable - does not degrade the natural resources on which agriculture depends on

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6
Q

How can you increase crop production without expanding the area?

A
  • Grow High Yielding Cultivars
  • Applying fertilisers
  • Reducing pests/diseases
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7
Q

Livestock production produces … due to energy lost between trophic levels.

A

Livestock production produces less food per unit area than crop plants due to energy lost between trophic levels

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8
Q

What advantage is there to using livestock over crop plants?

A

Livestock production is often possible where crop plants cannot be grown, i.e. a very steep hill.

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9
Q

What is the word equation for photosynthesis?

A

Carbon Dioxide + Water —> Glucose + Oxygen

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10
Q

What are some factors that affect the rate of photosynthesis?

A

Carbon dioxide availability
Temperature
Light intensity

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11
Q

Why are plants produce more food per unit area than livestock?

A

Due to the energy loss at each tropic level

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12
Q

Why are livestock sometimes chosen over plant production in certain areas?

A

Chosen in areas unsuitable for plant growth due to ability to grow (eg. mountains)

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13
Q

What is plant productivity?

A

Rate at which light energy is converted to glucose in photosynthesis

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14
Q

What is the biological yield of a plant?

A

Total increase in biomass

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15
Q

What are the two stages in photosynthesis?

A

Light Dependant Stage

Calvin Cycle

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16
Q

Where does the light dependant stage take place?

A

Chloroplasts

17
Q

Where does the Calvin Cycle take place?

A

Chloroplasts

18
Q

What are the three fates of light hitting a leaf?

A
  • Absorbed
  • Reflected
  • Transmitted
19
Q

What is the main photosynthetic pigment?

A

Chlorophyll a

20
Q

What regions of the absorption spectrum does chlorophyll A absorb light from?

A

Red & Blue

21
Q

What are the two accessory pigments called?

A

Carotenoids

22
Q

State an advantage of having accessory pigments

A

Extend the absorption spectrum and pass energy to chlorophyll

23
Q

Which regions of the absorption spectrum do the carotenoids absorb?

A

Yellow and Green

24
Q

Define the ‘Absorption Spectrum’

A

Absorption spectrum shows which colours of light are absorbed by the photosynthetic pigments

25
Q

Define the ‘Action Spectrum’

A

Action Spectrum shows the rate of photosynthesis at each light wavelength (colour).

26
Q

How can pigments in a leaf be extracted?

A

Thin Layer Chromatography

27
Q

What is the role of light energy in the production of ATP?

A

Light energy excites the electrons and puts them in a high energy state

28
Q

Which co-enzyme is responsible for picking up hydrogen?

A

NADP

29
Q

What does NADP become after picking up hydrogen?

A

NADPH

30
Q

What two products of the light dependant stage enter the calvin cycle?

A

NADPH and ATP

31
Q

What is the energy used for in photolysis?

A

To split water into hydrogen and oxygen

32
Q

ATP synthase is an enzyme that …

A

ATP synthase is an enzyme that generates ATP by the flow of Hydrogen ions passing through it

33
Q

Describe what happens to oxygen after photosynthesis?

A

Oxygen exits the plant via the stomata.

34
Q

List the steps of the light dependent stage of photosynthesis?

A

1 - Consists of a series of carrier proteins attached to the inner mitochondrial membrane.
2 - electrons become excited
3 - electrons transferred along an electron transport chain releasing energy.
4 - Energy is used by the enzyme ATP synthase to generate ATP
5 - Energy is also used for photolysis (split water) into hydrogen and oxygen
6 - Hydrogen picked by coenzyme NADP to make NADPH for carbon fixation stage.
7 - Oxygen evolved as gas through stomata

35
Q

Describe the steps of carbon fixation (calvin cycle) of photosynthesis?

A

1 - the enzyme RuBisCO fixes carbon dioxide by attaching it to ribulose bisphosphate (RuBP) to produce 3-phosphoglycerate (3PG)
2 - The 3-phosphoglycerate (3PG) produced is phosphorylated by ATP and combined with hydrogen ions from NADPH to form glyceraldehyde-3-phosphate (G3P). Both the hydrogen and the ATP are generated during the light dependent stage.
3 - G3P is used for the synthesis of glucose and the regeneration of RuBP.

36
Q

What is the full chemical name of the 3PG, which is involved in photosynthesis?

A

3-phosphoglycerate (3PG)

37
Q

What is the full chemical name of the G3P, which is involved in photosynthesis?

A

glyceraldehyde-3-phosphate (G3P)

38
Q

What are the fates of the glucose produced as a result of photosynthesis?

A

1 - used as a respiratory substrate to generate energy (ATP)
2 - converted to cellulose (structural carbohydrate)
3 - converted into starch (storage carbohydrate)
4 - used in other biosynthetic pathways (to make DNA, protein etc.)