5a: Food Production Flashcards
(10 cards)
How is the soil controlled for higher yield
- Minerals- fertilisers/ manure or crop grown in hydroponic culture: extra ions taken up for protein (growth)
- Structure- ploughing fields- break compacted soil, manure to improve drainage and aeration- better uptake ions and water
- pH- lime (calcium salts) to acidic soils- neutralise
Pests
Organisms that reduce yield of crop plants or stock animals causing economic damage to farmer
Chemical pesticides
Herbicides (weed)
Insecticides
Fungicides
Molluscides
Disadvantages of chemical pesticides
- resistance by chance mutation and natural selection
- environmental damage- persist in soil, accumulated along food chains
•bio accumulation: pesticides stored in fatty tissue amount builds up over time
-bio magnification: pesticides concentration increases in animal tissue
•expensive
Biological pest control
- predators (ladybird eat aphids)
- parasites (flies lay eggs on slugs, eventually kills them)
- disease causing, pathogenic (bacteria affect caterpillars)
- sterile males- no offspring from matings
- pheromones to attract/ trap pests (animal sex hormones to attract pests then destroyed)
Advantages/ disadvantages of biological pest control
Long lasting time, better for wildlife
Introducing new organisms cause problems (cane toads in Australia to eat beetles- but became pest as poisoned native species that eat them)
Role of yeast in production of beer
- REMOVE SUGAR IN GRAIN
• barley grains germinate, starch in grains broken down to sugar by enzymes (amylase)
•grains dried in kiln - MALTING
- malt ground to grist
- grist mixed with water (sugary solution/ wort) heated (enzymes)
• HOPS added for flavour
- Wort is ❄ SO YEAST NOT killed
• YEAST added, incubated (warmed)
•ferments the sugar into alcohol
•over when no more bubbles as killed (due to rising conc alcohol diff species tolerate diff levels of ) - Beer drawn off through too- clarifying agents added to remove particles- clearer
- PASTEURISED
• heated to kill yeast
How can glasshouses and poly tunnels increase yield of certain crops
- Keeping plants enclosed keeps them free from pests and diseases
- Artificial light, glasshouse transparent material. Short wave radiation entering becomes longer and cannot leave easily
- Heat and CO2- burning fossil fuels, traps Suns heat
- Watering- burning fuels (vapour), reduce water loss by transpiration
(More photosynthesis, plants grow faster and bigger- crop yield higher)
Investigating CO2 production by yeast
- Mix sugar, yeast and distilled water to test tube
- Bung with tube to second test tube
- Place yeast mixture in water bath at temp
- Count bubbles produced in given amount of time- calculate rate of C02 (respiration rate)
- Repeat at different temps
Control test tube of boiled - killed yeast
As temp increases, respiration increases as controlled by enzymes
Role of bacteria in production of yoghurt
LACTOBACILLUS
