Key Area 3.1 Flashcards
How can yield be improved
- Adding fertilisers
- higher yielding cultivars
- herbicides and fungicides for competition or diseases
- pest resistant crops
Why do plant have more energy than livestock
90% of energy is lost between tropic levels so plants have shorter food chains therefore lose less energy
How can livestock be more efficient than growing crops
And give an example
More efficient on land that crops can’t be grown on
E.g. Goats on rocky hills
3 fates of light?
Absorbed
Reflected
Transmitted
Name the 3 main pigments that absorb light
AND
what colours do each of these pigments absorb
•chlorophyll a:
Violet, Blue, Red
•chlorophyll b:
Violet, Blue, Orange
•Carotene:
Yellow red
•xanthophyll
What is food security
The ability of human population to access food of sufficient quality and quantity
What is an absorption spectrum and an action spectrum
Absorption - shows the absorption of light at each wavelength by each pigment
Action - shows the rate of photosynthesis at each wavelength
What is the case if the absorption spectra is low but the action spectra remains high
Other pigments are involved other than chlorophyll a, b, and carotene.
Name two accessory pigments and why they are advantageous in plants
Carotene, Xanthophyll
Allows plants to carry out photosynthesis at a wider range of wavelengths
How do accessory pigments allows photosynthesis to be carried out at a wider range of wavelengths
By passing energy they capture to chlorophyll a and b
Name and describe two main structures in the chloroplasts
Grana - photosynthetic pigments contained in here
Photolysis occurs here.
Storma - carbon fixation occurs here
2 stages of photosynthesis?
Photolysis
Carbon cycle/ carbon fixation
What is the word equation for photosynthesis
CO2 + water –(light energy)–> glucose + oxygen
Describe the process of photolysis
1) Absorbed light energy excites the electrons of the pigments and raises them to a high energy state
2) HEE captured by the primary energy acceptor
((The HEE then either …))
3) HEE flow along the Electron Transport Chain releasing energy by making a molecules of ATP, from ADP + Pi, while using the enzyme ATP synthase
4) HEE are used to break water molecules into water and hydrogen. The hydrogen is picked up my NADP to form NADPH (it’s a hydrogen acceptor)
5) Both NADPH and ATP are required for next stage
Describe the Calvin cycle
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1) CO2 enters the cycle and attaches to RuBP. There action is controlled by the enzyme RuBisCO
2) the CO2 and RuBP combine to make 3-phosphoglycerate
4) 3-phosphoglycerate is phosphorolated by adding Pi from ATP and combines with a hydrogen from NADPH to make G3P
5) some G3P used to regenerate RuBP and keep the cycle going and some is used to synthesise sugars
What are the fates of sugars
Respiration
Starch
Cellulose
Biosynthesis pathways e.g. Fats and oils and proteins
What is productivity and how is it measured
Productivity:
the rage at which plants in an ecosystem generate new biomass
Measured:
Unit of new biomass/ unit of area/ unit of time
Name factors that can affect plant productivity
Anything that affects photosynthesis so limiting factors
- Temperature
- Light intensity
- CO2 concentration
Why is plant productivity affected by factors affecting photosynthesis
If it affects photosynthesis it affects the ability or rate biomass is generated
What is assimilation and what does this process cause
Assimilation:
Conversion of glucose into complex components of the plant cell
Effects:
Increases the plants biomass
How can bet assimilation be calculated
(Gain in dry mass due to photosynthesis) - (loss in dry mass due to respiration)
What is biological yield and why is it useful
Biological yield:
Total biomass of plant produced
Useful?
Shows the producing potential of the land
What is economic yield?
Mass of desired product
How to calculate the harvest index
Economic yield / biological yield
