5702361
| Pregunta | Respuesta |
| Explain how human population growth has occurred. | because the birth rate is greater than the death rate -people not using contraception -vaccines preventing death |
| Explain why raw materials are rapidly being used up and more waste is being produced. | people want and demand a better standard of living |
| Describe the effects of population growth on land and resources. | -producing more industrial waste -reduce land available for animals/plants -waterways with sewage, fertiliser & toxic chemicals -pollute air with gases such as sulfur dioxide |
| Describe how pesticides and herbicides can pollute the land. | herbicides & pesticides are sprayed onto crops then get into the soil & food chain; eventually get washed into water |
| Describe what happens when water is polluted by fertilisers. | fish/marine life killed by chemicals, affecting the food chain drinking water becomes poisonous to drink without filtration |
| Describe how acid rain is formed. | -burning fuels can produce sulfur dioxide -dissolves in water in air, forming acidic solutions -fall as acid rain, sometimes far from source of gas |
| Describe some of the effects of acid rain on living organisms. | -kills organisms -changes soil pH, damaging roots & possibly releasing toxic minerals (e.g. aluminium ions damaging organisms) -affects enzymes, which are sensitive to pH |
| Define ‘deforestation’ | the removal of forests/trees by felling, burning, etc. |
| Describe ways in which deforestation affects the carbon dioxide levels in the atmosphere. | -increased release of CO2 due to burning of trees or decay of wood by microorganisms -reduced rate of photosynthesis so CO2 removed from atmosphere slower |
| Describe ways in which deforestation affects the methane levels in the atmosphere. | increases in cattle and rice fields for food, therefore more methane produced by cattle and growing rice |
| Describe the impact of deforestation on biodiversity. | loss of food and habitats therefore species cannot survive - reduced biodiversity |
| Explain why the use of peat-free compost should be encouraged. | prevents destruction of peat bogs which releases CO2 into atmosphere: peat removed from bogs & used in compost - this is decayed by microorganisms |
| Describe what is meant by the ‘greenhouse effect’. | trapping of infrared radiation from sun as a result of greenhouse gases (e.g. CO2/methane) in Earth's atmosphere maintains surface of Earth at temp. suitable for life |
| Describe how increasing levels of carbon dioxide and methane contribute to global warming. | they trap too much energy in atmosphere, preventing it from reflecting into space, leading to a rise in global temperature |
| Describe some of the consequences of global warming. | -rise in sea levels due to melting of icecaps/glaciers -changes to migration patterns -reduced biodiversity -climate change |
| Describe how yeast can produce ethanol for fuel. | FERMENTATION: -microorganisms respire anaerobically, using sugars from crops as energy source -glucose (produced by maize starch and carbohydrase) and sugar cane juices are fermented by yeast -extracted by distillation |
| Describe the advantages and disadvantages of using ethanol-based fuels. | + carbon neutral + reduces greenhouse effect - batch process - slow |
| Explain how biogas is produced in a generator. | -(mainly methane) produced during anaerobic fermentation by bacteria -dung, farm waste & animal rubbish put in -maintained at suitable temperature in O2- free conditions -more methane=better quality biogas |
| Evaluate the advantages and disadvantages of given designs of biogas generator. | -buried in ground or have insulating jackets -large scale: use waste from factories or sewage works) -small scale: used by a home or farm |
| Explain why reducing the number of stages in a food chain makes food production more efficient. | the shorter the chain, the less energy will be wasted, as energy is lost at each trophic level |
| Describe ways in which energy losses by animals can be reduced. | -preventing animal from moving so energy not wasted on movement -keeping animal in warm shed so not using as much energy to maintain body temp. -fed food high in energy |
| Explain the need for increased food production. | human population is increasing and food resources are at risk of running out |
| Describe ways in which fish stocks can be maintained. | -quota: only remove a strict allocation of fish per year -must use certain size nets to avoid catching small, young fish |
| Describe the production of mycoprotein. | fungus fusarium grown anaerobically on cheap sugar syrup made from waste starch |
| Features of a fermenter ensure max growth of fusarium: | -air supply providing O2 for respiration -stirrers/gas bubbles to keep temp. even & spread out microorganisms -water-cooled jacket around outside to maintain temp. as respiring MOs release energy which heats contents -sensors to monitor pH & temp. |
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