Biotechnology
Explain why the contents of the fermenter are stirred constantly.
ensures even or uniform distribution of contents
Describe what is meant by decomposers
organism) that gets its energy, from dead / waste organic, material ;
State one effect of deforestation on the environment.
• Contribution to global warming
Define the term genetic engineering?
idea that gene(s) are transferred ; A genetic information / DNA R chromosome from one, species / organism, to another, species / organism ;
Describe the roles of the soil organisms in the carbon cycle
ref to, respiration/ decomposition ; release carbon dioxide ; carbon dioxide is taken in by, plants /photosynthesis ;
Yields from crops grown on soils are likely to decrease over time.
State reasons for the likely decrease in yields.
soils, are thin / have little humus content ; no / less, recycling organic material ; competition for minerals from crop ;
constant cultivation, removes / overuses, minerals;
plant pest population increases ;
Bacteria are useful in biotechnology and _____ engineering due to their ______ reproduction rate and their ability to make ______ molecules.
genetic, rapid, complex
Explain the term ecosystem
Describe an ecosystem as a unit containing the community of organisms and their environment, interacting together
Overfishing is one reason why populations of fish decline. Explain the risks to a species if its population size decreases.
any three from: reduction in genetic variation / reduced gene pool ; inbreeding ; idea of an increase in the frequency of recessive alleles ; (described) consequence of having too many recessive alleles ; risk of extinction ; idea of unable to find mates / AW ; AVP ;
1. Discuss the advantages and disadvantages of genetic modification of crop plants.
total of four from:
max three advantages from: increased, yield / quantity ; increased nutritional, quality / content ; reduced use of fertiliser ; decrease damage from pests ; resistance to (insect) pests / (crops) produce insecticide / reduced use of insecticides ; resistance to, herbicides ; resistance to disease ; resistance to, salinity / cold / drought / AW ; max three disadvantages from: (genetically modified) seeds / plants, cost more (to farmer / consumer) ; (genetically modified) seeds, are sterile / need to be bought for each new crop ; (modified) genes may transfer into other (nearby) plants by cross pollination / AW ; ethical / religious, concerns about altering natural genomes / of consumers ; disruption of food chain by pest losing food source ; reduced genetic variability (of the crop) / (crop) less able to adapt to a change in the environment ;
Animals such as salmon can be farmed for meat. Explain why it is more energy efficient for humans to eat crop plants than to eat livestock that have been fed on crop plants.
ny four from: as fewer trophic levels / plants are at a lower trophic level (than salmon / livestock) ; ora idea that energy transfer along food chain is inefficient ; (energy lost in) respiration / heat / (named) metabolic process / movement / muscle contraction ; ref to (more) material that is lost as, faeces / egested / inedible / not digestible (in longer food chains) ; (energy lost in) excretion / urine ;
Two species of slender loris are found in Sri Lanka, the grey slender loris, L. lydekkerianus, and L. tardigradus.
The International Union for Conservation of Nature describes the red slender loris as endangered. Horton Plains National Park in Sri Lanka is one of the few places where
L. tardigrad is found.
(d) Discuss why areas of land, such as the Horton Plains National Park, must be conserved.
ive some protection for endangered species / prevent extinction;
encourages biodiversity; maintains (natural) habitats; encourages genetic diversity; maintain food, webs / chains ;
services that wild places provide ; increasing awareness / education / research ;
Coffee beans are often processed using a wet fermentation method, where microorganisms such as yeast break down sugars in the pulp surrounding the beans.
A student wants to investigate the role of yeast in this fermentation process.
3 and 4 - method
1 - independant
2 - dependant
5,6,7 constant
8 safety precaution - Wear eye protection, Take care with hot water bath,
A student found the following information about the feeding relationships between some organisms in a soil habitat.
Dead organic matter, such as leaves, provides food for bacteria and soil fungi. Earthworms eat dead leaves. Many millipedes feed on dead plant matter and also on soil fungi. Nematodes feed on bacteria and are eaten by springtails. Centipedes are predators that feed on earthworms, millipedes and springtails.
Draw a food web to show the feeding relationships described above.
ll arrows point from food to feeder ; millipedes eat dead leaves and fungi ; food chain : bacteria ? nematodes ? springtails ? centipedes ; centipedes eat millipedes, springtails and earthworms ;
Describe why conservation projects such as seed banks are important
five from: maintaining / increasing biodiversity ; reduce (plant) extinction ; preventing loss of animal species that depend on plant species ; (moral) responsibility to save other species ; protect / maintain, (vulnerable / AW) ecosystems ; by supporting recycling of nutrients ; by supporting flow of energy in, food chains / food webs ; possible fuels ; possible genes ; possible drug sources ; possible crop plants / selective breeding ; allows for future research ; AVP ;;