food production Flashcards
how are glasshouses useful to increase crop yields
provides an enclosed environments so farmers can control the the climate inside
factors that can be manipulated in glasshouses
heating
lighting
CO2 cocntent
regular watering
polythene tunnels
large plastic tunnels that cover crops
what do polythene tunnels do
protect crops grown outside from the effect of weather
- increase temp
- prevent entry of pest
fetillizers
increase amount of key nutrients in soil
pesticides
chemicals kill off unwanted insects and weed species
types of fertillizers
organic fertillizers
chemical fertillizers
Organic fertiliser
compost or farmyard manure
chemical fertilisers
applied to soil as dry granules or sprayed on in liquid form
lack of nitrogen in plants
weak growth and yellowing of leaves
lack of phosphorus in plants
poor root growth and discolored leaves
use of potassium in plants
allows enzyme reactions to take place to produce ATP
lack of potassium in plants
poor growth of flowers
brown spots on leaves
why are weeds bad for crops
compete for space, water and nutrients
why are fungi bad for crops
infect crop plants, and spread disease
advantages of pesticides
- cheap
- accesible
- have immediate effect
- kills entire population of pests
disadvantages of pesticides
- build resistance
- kill other organisms
- persistent chemicals
- repeatedly applied
biological control
species introduced specifically to prey on pest
advantages of biological control
no pollution
no resistance
target specific spiecies
long lasting
disadvantages of biological control
- they eat other organisms
- long time to be effective
- cant kill entire population
- may not adapt to new environment
what is yeast
a single celled fungus that can carry out both types of respiration
products when yeast carries out anaerobic respiration
ethanol and co2
making bread process
- enzymes break down starch in flour releasing sugar
- CO2 produced by yeast during anaerobic respiration is trapped in small air pockets
- dough rises and baked
what happens to the ethanol in the bread when its baked
it gets evaporated
what is anaerobic respiration in yeast cells called
fermentation
why are bacteria useful
capable of producing complex molecules
- reproduce rapidly
what heat is milk pasteurised at
85-95 degrees celcius
why is it important to sterilise all equipment when making yoghurt
to kill unwanted bacteria and prevent chemical contamination
why would contamination of other bacteria be bad for yoghurt
slows down the production of yoghurt by competing with lactobacillus
why is yoghurt incubated
for lactobacillus to digest milk proteins and ferment the sugar
why is lactobacillus bacteria important for yoghurt production
converts lactose into lactic acid and increases the acidity and thickens milk
what a fermenters
containers used to culture microorganisms like bacteria and fungi in large amounts
what are fermenters used for
production of beer and yoghurt
advantages of fermenters
conditions can be carefully controlled to produce large quantities of right type of microorganism
what has led to declines in fish population
overfishing
fish farms
ways of raising large numbers of fish in small space to provide protein
advantages of fish farm
- selectively breed to ensure high quality
- protect against predators
- control water quality
- control feeding
