sustainability and interdependence Flashcards
What is food security?
Food security is the ability of human populations to access food of sufficient quality and quantity.
What does increase in human population and concern for food lead to?
Increase in human population and concern for food security leads to demand for increased food production.
What must food production be?
Food production must be sustainable and not degrade the natural resources on which agriculture depends.
What does agricultural production depend on?
Agricultural production depends on factors that control photosynthesis and plant growth.
What factors does increased food production depend on? What are these 5 things?
Increased food production will depend on factors that control plant growth - breeding for higher yielding cultivars, use of fertiliser, protecting crops from pests, diseases and competition.
What is all food production dependent upon?
All food production is dependent ultimately upon photosynthesis.
Name 4 examples of plant crops?
Plant crop examples include cereals, potato, roots and legumes.
What 4 things do breeders seek to develop crops with?
Breeders seek to develop crops with higher nutritional values, resistance to pests and diseases, physical characteristics suited to rearing and harvesting as well as those that can thrive in particular environmental conditions.
What do livestock produce less of than crop and plants? What is this due to?
Livestock produce less food per unit area than crop plants due to loss of energy between trophic levels.
What is livestock production often possible in?
Livestock production is often possible in habitats unsuitable for growing crops.
What is light energy absorbed by? What does this generate?
Light energy is absorbed by photosynthetic pigments to generate ATP and for photolysis.
What happens to the light energy not absorbed?
Light energy not absorbed is transmitted or reflected.
Absorption spectra of what?
Absorption spectra of chlorophyll a and b and carotenoids compared to action spectra for photosynthesis.
What do Carotenoids do?
Carotenoids extend the range of wavelengths absorbed and pass the energy to chlorophyll for photosynthesis.
What does each pigment do?
Each pigment absorbs a different range of wavelengths of light.
What does absorbed light energy do?
Absorbed light energy excites electrons in the pigment molecule.
What does transfer of these electrons through the electron transport chain do?
Transfer of these electrons through the electron transport chain releases energy to generate ATP by ATP synthase.
What happens during photolysis?
Energy is also used for photolysis, in which water is split into oxygen, which is evolved, and hydrogen, which is transferred to the coenzyme NADP.
What happens in the carbon fixation stage?
In the carbon fixation stage (Calvin cycle), the enzyme RuBisCO fixes carbon dioxide by attaching it to ribulose bisphosphate (RuBP).
What happens to the 3-phosphoglycerate (3PG) produced?
The 3-phosphoglycerate (3PG) produced is phosphorylated by ATP and combined with hydrogen from NADPH to form glyceraldehyde- 3-phosphate (G3P).
What is G3P used for?
G3P is used to regenerate RuBP and for the synthesis of glucose.
Summarise Photosynthesis
Absorbed light energy excites electrons in the pigment molecule.
Transfer of these electrons through the electron transport chain releases energy to generate ATP by ATP synthase.
Energy is also used for photolysis, in which water is split into oxygen, which is evolved, and hydrogen, which is transferred to the coenzyme NADP.
In the carbon fixation stage (Calvin cycle), the enzyme RuBisCO fixes carbon dioxide by attaching it to ribulose bisphosphate (RuBP).
The 3-phosphoglycerate (3PG) produced is phosphorylated by ATP and combined with hydrogen from NADPH to form glyceraldehyde- 3-phosphate (G3P).
G3P is used to regenerate RuBP and for the synthesis of glucose.
Glucose may be used as a respiratory substrate, synthesised into starch or cellulose or passed to other biosynthetic pathways.
These biosynthetic pathways can lead to the formation of a variety of metabolites such as DNA, protein and fat.
What may glucose be used as?
Glucose may be used as a respiratory substrate, synthesised into starch or cellulose or passed to other biosynthetic pathways.
What can these biosynthetic pathways lead to?
These biosynthetic pathways can lead to the formation of a variety of metabolites such as DNA, protein and fat.