food production- topic 17

• the effect of increased carbon dioxide on crop yield, fossil fuels are burnt carbon dioxide is released as waste product which is used by plants as a reactant in photosynthesis, also increases concentration of water vapour in the air which means less water lost in the plant in transpiration
• in glasshouses and polythene tunnels, factors required for photosynthesis can be optimised and controlled in these environments
• toxins in the food chain, bioaccumulation, primary plants containing toxins, secondary then eat the primary and so on so toxins end up in the food chain
• organic farming involves use of manure and straw it has a low efficiency as mineral concentration can't be controlled however it has a positive impact of the environment
• inorganic farming involves using artificial chemicals which has a high efficiency as mineral concentration can be carefully controlled however it has a negative impact on the environment as it can lead to eutrophication
• yeast is a beneficial fungi which can turn flour into bread, fungi uses the glucose sugar in the flour for fermentation glucose-ethanol plus carbon dioxide, the ethanol evaporates during baking, carbon dioxide causes the dough to rise
• lactobacillus is a beneficial bacteria which turns milk into yoghurt, the bacteria uses the lactose sugar in the milk for fermentation lactose- lactic acid
• crop rotation is growing different types of crops in different soils over time to ensure that no one patch of soil becomes deficient of a certain mineral
• fermenters are large containers which contain microorganisms used to make useful products
• filter on air intlet stops microorganisms getting inside the fermenter, an aseptic precaution to prevent contamination by unwanted microorganisms
• steam inlet, hot steam sterilises the inside of the fermenter, an aseptic precaution to prevent contamination by unwanted microorganisms
• air inlet, provides a source of oxygen and microorganisms need oxygen for aerobic respiration
• water jacket with cooling water, keeps the temperature inside constant, micro-organisms grow best at an optimum temperature
• nutrient inlet, allows sterile nutrients to enter the fermenter, microorganisms need nutrients so that they can grow and reproduce
• biological control is when another living organism (such as a natural predator)is introduced to control the pest rather then a chemical e.g ladybirds kill aphids
• advantages of biological control is, less likely to develop resistance, better targeted to pests (less damage to other species), good in enclosed spaces
• disadvantages of biological control, slower to act then pesticides, introduced species may have unforeseen consequences, may not work well in open areas
• eating fish, protein is broken down by amino acids by protease which is found in the stomach
• advantages of pesticides, remove large proportion of pests quickly, easy to apply
• disadvantages of pesticides, may develop resistance, damage other species, predator killed meaning more pests
• stirring paddles, keeps the mixture inside the fermenter stirred to distribute the oxygen and keep the temperature even
• temperature recorder, monitors the temperature and turns on water supply, prevents enzymes from being denatured
• stages of bread making, add yeast to dough, knead the dough, allow the yeast to ferment during this time carbon dioxide will be produced which causes the dough to rise, bake in oven
• how to make yoghurt, pasteurisation of the milk, to kill unwanted bacteria, reduce the temperature, add lactobacillus bacteria
• interspecific predation is between different species, use of nets prevent predation
• infraspecific predation, within the same species, fish are separated by age and size to prevent larger fish eating them, fish are provided with sufficient food to prevent starvation and reduce predation
• control of disease, antibiotics are used to prevent disease and increase fish growth however this can cause antibiotic resistance in humans
• removal of waste products, water in the tanks is filtered to remove the waste, however the waste water which goes into the river or sea can also cause eutrophication
• maintenance of water quality, temperature and oxygen of the water can be controlled, in unfiltered water there is more bacteria, therefore less oxygen in the water for the fish, fish conduct less aerobic respiration, therefore less growth by the fish
• selective breeding, fish with have desired characteristics are selected for breeding, repeat over several generations so that the genes for desired characteristics are passed on, yield and profit maximised
• feeding, feed small quantities of protein rich food very regularly to maximise growth, fish food pellets are made from smaller fish (sardines) which causes further decrease in fish, pellets can also contain antibiotics
• nitrates- amino acids for protein help plant growth
• magnesium- chlorophyll for photosynthesis
• heaters can be used to increase and maintain temperature so that it is optimum for the enzymes controlling photosynthesis, optimum temp means particles have more kinetic energy, more photosynthesis so more carbohydrates and more respiration