Biology - Food supply, plant growth and productivity

what is food security?

the ability of human population to access food of sufficient quality and quantity

food production must be ?

sustainable

what is all food production dependent on?

photosynthesis

factors that control plant growth

breeding of higher cultivars, use of fertiliser, protecting crops from pests, diseases and competition

Why do livestock produce less food per unit area than plant crops?

loss of energy between trophic levels

fate of light in leaves

absorbed, reflected, transmitted

what can be used to measure absorption of light?

spectroscope, spectrophotometer, colourimeter

what colour does chlorophyll a and b absorb?

red and blue wavelenghts

What do carotenoids do?

extend the range of wavelengths absorbed and pass the energy to chlorophyll for photosynthesis

products of carbon fixation (calvin cycle)

glucose

what can glucose be used for?

cellulose, respiration, stored as starch