Use of Biological Resources - GCSE Flashcards
what is a plant’s rate of photosynthesis affected by?
- the amount of light
- the amount of carbon dioxide
- the temperature
why do plants do photosynthesis?
they do it in order to make food for themselves and grow
how can photosynthesis be helped?
by artificially creating the ideal conditions in glasshouses or polytunnels
why is keeping plants enclosed in a glasshouse better?
there are 5 looong points
- easier to keep them free from pests and diseases
- helps farmers control the water supplied to their crops
- traps the Sun’s heat to keep the plants warm. In winter farmers might even use heaters to keep temperature at an ideal level
- farmers often supply artificial light after the Sun goes down to give their plants more time to photosynthesise
- farmers can increase the level of carbon dioxide in glasshouse
why is it a good idea to put your plants inside a glasshouse?
because in a glass house you will be able to control the conditions your plants are living in.
for example: by increasing the temperature and CO2 concentration and amount of light available a farmer can increase the rate of photosynthesis. This means the plants will grow bigger and faster (and crop yields will be higher)
why do plants need certain minerals?
to make important compounds like proteins
what happens if plants don’t get enough minerals?
their growth and life process are affected
why are minerals sometimes missing from the soil?
because they’ve been used up by a previous crop
why do farmers use fertilisers?
to replace these missing minerals or provide more of them. This helps to increase the crop yield
what are pests?
they are microorganisms, insects or mamals that eat crops
what is the advantage of killing pests?
fewer plants are damaged or destroyed, increasing crop yield
what is crop yield?
Crop yield is a standard measurement of the amount of agricultural production
what is pesticides?
it is a form of chemical pest control. They are often poisonous to humans so they must be used carefully. It can also be harmful to other wildlife
what is biological control?
it is an alternative to using pesticides. It means using other organisms to reduce the numbers of pests either by encouraging wild organisms or adding new ones
what are good organisms to use for killing pests? (biological control)
- predators
- parasites
- disease-causing
why is biological control considered better than pesticides?
- has a longer lasting effect
- less harmful to wildlife
why can biological control be bad sometimes? Give an example
because introducing new organisms can cause problems
eg. cane toads were introduced to Australia to eat beetles, but they are now a major pest themselves because they poison the native species that eat them
what is fermentation?
it is when microorganisms break sugars down to release energy, usually by anaerobic respiration.
what is yoghurt?
fermented milk
how do you make yoghurt?
there are 6 steps
1) the equipment is sterilised to kill off any unwanted microorganisms
2) milk is pasteurised (heated up to 72 degrees for 15 seconds) to kill any harmful microorganisms. Then the milk’s cooled
3) lactobacillus bacteria are added and the mixture is incubated (heated to about 40 degrees) in a vessel called a fermenter
4) the bacteria ferment the lactose sugar in the milk to form lactic acid
5) lactic acid causes the milk to clot, and solidify into yoghurt
6) finally, flavours and colours are sometimes added and the yoghurt is packaged
what really useful stuff can microorganism (like bacteria) make?
penicillin or insulin
in industry, where are microorganisms grown?
in a large containers called fermenters. The fermenter is full of liquid ‘culture medium’ in which microorganisms can grow and reproduce