Biological Resources Flashcards
Describe how glasshouses and polytunnels can be used to increase the yield of certain crops
Glass provides greenhouse effect (traps heat); paraffin heaters provide heat and CO2 for increased photosynthesis; artificial lights mean crops can grow into the night and out of season; pests can be controlled easily; can easily control nutrition of crops being grown; protection from disease; control how much water is supplied to plants
Describe the role of fertiliser in increasing crop yields
Can control exactly what mineral ions, e.g. magnesium and nitrates, the plants are getting; constant, effective growth
State a danger of fertilizer use on fields of crops
Can leach into water ways and cause eutrophication
Why might we want to use chemical pesticides?
Kill pests and increase crop yields
Give three advantages of biological control over pesticides
No bioaccumulation (building up of toxic chemicals in food chain); specific to certain pests (exploits natural predator-prey relationships); no need to reapply (lowers cost compared to pesticides); no resistance forms; longer lasting
State two commercial products that yeast can be used to make industrially
Bread, beer
What species of bacteria can be used to make yoghurt? How does this work?
Lactobacillus; respires anaerobically and ferment lactose in milk to produce lactic acid; lactate coagulates milk proteins and causes milk to thicken
Write a word equation for the anaerobic respiration of yeast
Glucose –> Ethanol + carbon dioxide
Suggest two products that could be produced on a large scale using a fermenter
Insulin, penicillin (antibiotic)
Why must conditions in a fermenter remain aseptic?
To prevent infection, disease or contamination of product
Why might sterile air be pumped into a fermenter
To allow the bacteria to respire aerobically, providing energy for growth; sterility of air means less chance of contamination
Why are there paddles in a fermenter?
To agitate the fluid, evenly distributing oxygen and nutrients
Why might a fermenter be surrounded with a water jacket?
To cool the tank and ensure optimum temperature is achieved for enzymes
What chemical could be used to test whether yeast are respiring anaerobically?
Bubble gas produced into limewater; turns cloudy
Fish are a good source of which major nutrient?
Protein (fish diet can be carefully controlled in a fish farm)
Why must water quality be monitored and maintained in fish farms?
Ensures pH, temperature and oxygen levels are appropriate; water can be removed and filtered to remove waste and faeces avoiding pollution
How is intraspecific predation controlled in fish farms?
Younger fish are kept separate from bigger fish so that the big fish do not eat the little ones
How is interspecific predation controlled in fish farms?
Fish are kept in cages in the sea to protect them from being eaten by other species (nets can be used too)
How is disease prevented in fish farms?
Antibiotics can be used; biological control agents can be used to avoid parasites
How might selective breeding be important in a fish farm?
Produces fish that are larger, higher quality and less aggressive
Why might we use selective breeding be used to develop plants and animals with desired characteristics?
Can ensure maximum yield of meat, milk grain etc.; can breed plants resistant to frost, drought or disease; can breed animals with good temperaments, fertility etc.; can breed plants with nice smell, wheat with large seeds etc.
Describe the basic process involved in selective breeding?
From existing stock, select organisms with best characteristics; breed them with each other; select best offspring and breed those together; continue over many generations until the trait (allele frequency) gets stronger and stronger
How are restriction enzymes used in genetic engineering?
Used to cut DNA at specific sites and remove required gene; same restriction enzyme used to cut open plasmid so sticky ends are complementary
How is DNA ligase used in genetic engineering?
Used to join pieces of DNA together, i.e. to stick the required gene into a plasmid
