food production Flashcards
how do greenhouses and polythene tunnels increase crop yields
as conditions are kept at the optimum for growth including the use of artificial lighting and trapping heat from the sun
how do increased temperatures increase the crop yield
- enzymes work more efficiently at higher temperatures and reaction rates are faster
- enzymes are involved in key growth processes and photosynthesis
how does a continuous supply of enough carbon dioxide increase the crop yield
- CO2 is needed for photosynthesis which is needed to provide energy for growth
- without a constant supply of CO2 it may become a limiting factor and so the rate of photosynthesis is slower
why are fertilizers good for crop yield
they provide nutrients for the plant which are needed for growth to make the crops large and give a plentiful yield
what are three disadvantages of pesticides
- they are not specific and so can kill other insects that are not pests
- they can contaminate water sources
- they have to be applied more than once
how does yeast cause bread to rise
by breaking down the sugars in the bread in respiration and produces carbon dioxide which causes the bread to rise
how is yoghurt made from milk
- lactobacillus is used to break the lactose in milk down into lactic acid
- lactic acid lowers the pH of the milk which causes proteins to denature and makes the milk turn into yoghurt
what is a fermenter used for
to produce large cultures of microorganisms
what are five things than need to be controlled in an industrial fermenter
- temperature
- pH
- nutrient levels
- oxygen levels
- contamination
how is water quality maintained in fishing areas
by removing waste and killing pathogens
what is interspecific predation
where other species eat the fish
what is infraspecific predation
where the dish eat one another
