U3 KA1 Flashcards
(19 cards)
What is food security?
- the ability of human populations to have access to food of sufficient quality and quantity.
What is 1 global concern for food security?
- rapidly increasing global population, and increasing demand for food production.
How is food production increased? (3)
- through the breeding of higher breed cultivators.
- use of fertilisers.
- protection of crops from pests and diseases.
What are the limiting factors of agricultural production? (5)
- soil moisture, temperature, light availability, nutrient availability, pests.
How can agriculture production be improved? (3)
- using pesticides and fertilisers.
- breeding higher yield cultivars.
- crop protection.
What is a trophic level?
- an organisms place on the food web.
- eg. producer, primary consumer, etc.
Why are crops grown instead livestock?
- growing crops is more efficient, as over 90% of energy is lost between trophic levels.
Why is livestock produced instead of crops?
- livestock production is possible in areas that plants cannot grow.
What is photosynthesis?
- the process by which green plants take energy from sunlight, converting it to sugar.
What is chlorophyll A?
- the main pigment found in chloroplasts of plants that absorb light energy.
What is the role of chlorophyll B and carotenoids?
- to absorb light from other wavelengths, passing the energy to chlorophyll A.
- this allows the chloroplast to extend the range of absorbed wavelengths.
What happens to the light that is not absorbed by the plant? (2)
- reflected off the leaf.
- transmitted through the leaf.
What happens in stage 1 of Photosynthesis? (2)
- light is absorbed by pigments, exciting electrons.
- electrons are transferred through ETC, releasing energy used for Photolysis.
What happens in Photolysis?
- energy from ETC is used to split water into hydrogen and oxygen.
- hydrogen ions react with NADP to form NADPH.
What happens in carbon fixation?
- 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.
What are the uses of G3P? (2)
- regeneration of RuBP.
- synthesis of glucose.
What are the uses of glucose? (3)
- used as a respiratory substance.
- converted to starch.
- passed to biosynthetic pathways to form DNA, protein and fat.
Why does the concentration of RuBP increase, when Co2 concentration decreases? (2)
- there is less Co2 to combine with RuBP.
- 3PG is still regenerated to RuBP so it increases.
Why is algae immobilised into gel beads?
- is allows the algae and incubator to be separated easily.
