Biology Topic 9

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What are the ideal conditions for photosynthesis and how do you artificially create them?
Enclosed in glasshouse- free from pests+disease. Artificial light- more time for photosynthesis. Trap Sun's heat- keep warm. Increase the level of CO2- paraffin heater. Increasing the rate of photosynthesis for higher crop yields.
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How can fertilisers be used to ensure the crops have enough nutrients?
Contain the elements needed to make important compounds like proteins. Use them to replace these elements or make more of them.
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What is a form of pest control?
Pesticides, chemical pest control. Poisons to humans, have to be used carefully to keep food safe.
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What is biological control?
The use of other organisms to reduce the numbers of pests, either by encouraging wild organisms or adding new ones. EG Predators, parasites. Longer-lasting effect than pesticides, less harmful to wildlife. New organisms=issues.
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How do you use bacteria to ferment milk in order to produce yoghurt?
Equipment sterilised (kill organisms). Milk is pasteurised- heat up to 72degrees C for 15s- kill organisms- cool. Lactobacillus bacteria added- incubate (40dC) in a fermenter. Bacteria ferments the lactose sugar in milk- lactic acid clot. solidify.
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Define fermentation.
Microorganisms break sugars down to release energy- usually by anaerobic respiration.
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How are microorganisms frown in fermenters?
Fermenter is full of liquid - culture medium- microorganisms grown and reproduce.
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What are the optimum conditions inside a fermenter?
Nutrients-provided in culture medium. pH monitored-enzymes. Temperature- water-cooled jacket so not too hot. Microorganisms in contact w/ fresh medium by paddles-agitate medium around the vessels-access nutrients. O2. Vessels sterilised between use.
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How do you use yea
Get sugar out of grain. Yeast added- mix incubated. Y ferments into sugar->alcohol. Fermenting vessels stop unwanted microorganisms+air getting in. Beer drawn-off through a tap. Pasteurised-heated-kill yeast. Aged in right conditions. Casked-sale.
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How do you measure the reproduction rate of yeast depending on its conditions?
Mix sugar,yeast+distilled H2O. Add mix to test tube. Bung w/ tube attached leading to tube of H2O. Water bath-certain temperature. Leave, count production of bubbles. Rate of CO2 production- indication of respiration rate. Repeat,diff. temperatures.
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How can you make this experiment more accurate?
Replace the second tube with a gas syringe, to measure the volume of gas produced instead of bubbles.
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Define selective breading.
The mating of the best organisms to get good offspring.
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What are some ideal features?
Maximum yield of meat, milk, grain... Good health, disease resistance. Temperament, speed, fertility, mothering skills. Attractive flowers, smell...
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Why is selective breading useful in cows?
Increase the productivity of cows-high meat yield. Keep breading good ones together and eventually it'll be ideal.
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Why is selective breading useful in the number of offspring of sheep?
Ewes that produce large numbers of offspring- keep breading, passed onto next generation.
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Why is selective breading useful in the increase of crop yield?
Combine two different desirable characteristics. Cross-bread, new variety containing the good characteristics of both.
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Why are some fish farmed in cages in the sea?
Keep in there- stop using so much energy swimming. Protects from interspecific predation. Diet that's carefully controlled, maxamise energy. Special tanks for young fish- increase survival chances. More prone to disease and parasites eg sea lice.
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Why are some fish farmed in tanks?
Water can be monitored- pH, temperature, O2 level. Level of food, and type- control. Water can be removed and filtered- remove waste, clean for the fish, avoid pollution.
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What do restriction enzymes do?
Recognise specific sequences of DNA and cut the DNA at these points.
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What are ligase enzymes used for?
To join two pieces of DNA together.
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What is recombinant DNA?
Two different bits of DNA that are stuck together.
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What is a vector?
Something that's used to transfer DNA into a cell. There are two types- plasmids and viruses. Plasmids-small,circular molecules of DNA, can be transferred between bacteria. Viruses-insert DNA into affected organisms.
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How does genetic engineering work?
Restriction enzyme cuts what you want to insert. Vector DNA cut open using the same restriction enzyme. Both mix with ligase enzymes. Join-produce recombinant DNA. Inserted into other cells. Cells use the inserted gene to make desired protein.
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Describe the use of transgenic bacteria?
They contain genes transferred from another species. EG bacteria containing the human gene for insulin.
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How can genetically modified plants improve food production?
Resistant to insects, resistant to herbicides- don't spay as many pesticides- less wildlife harm+crop harm. Spray crops to kill weeds, not kill plants.
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How can you clone plants using micropropagation?
Desirable characteristics- plant chosen. Explants *small pieces* taken from the tips of stems+side shoots of plant. Sterilised, kill microorganisms. Grown in vitro- petri dish containing a nutrient medium+growth hormones. Divide+grow, planted in soil
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How is cloning an adult mammal done?
Transplanting a cell nucleus. Nucleus of sheeps egg cell removed, enucleated cell- diploid nucleus inserted in its place (from different sheep). Cell stimulated-electric shock- divide+multiply by mitosis- diving cell implanted other sheep.
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What are the advantages of cloning?
Animals produce medicines in their milk- useful to us. Organ transplant. Useful genetic characteristics are always passed on.
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What are the disadvantages of cloning?
Cloned animal may not be as healthy as normal ones- don't develop normally. Difficult, time-consuming, expensive, unknown effects.
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Card 2

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How can fertilisers be used to ensure the crops have enough nutrients?

Back

Contain the elements needed to make important compounds like proteins. Use them to replace these elements or make more of them.

Card 3

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What is a form of pest control?

Back

Preview of the front of card 3

Card 4

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What is biological control?

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Card 5

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How do you use bacteria to ferment milk in order to produce yoghurt?

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