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Flashcards in Section 9 - Use of Resources Deck (29)
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Describe the basic process of selective breeding [4 marks]

- Chose stock with the best characteristics

- Breed them with each other

- Select the best of the offspring, breed them together

- Continue over several generations, desirable traits get stronger and stronger


How can farmers artificially create ideal conditions for photosyenthesis (6)

- Keep plants enclosed in a greenhouse 

- To keep them free from pests and disease

- Apply artificial light after the sun goes down

- Give plants more time to photosyenthesis

- Use a parrafin heater

- Increases level of carbon dioxide


How does artifically creating the ideal temperature, light intensity and amount of carbon dioxide help farmers (3)

- Increases rate of photosyenthesis

- Plants will grow bigger and faster

- Crop yields will be higher


Why do farmers use fertilisers (7)

- Fertilisers are used to ensure crops have enough nutrients

- Nutrients e.g nitrates, phosphates, potassium

- Needed to make protein

- Growth and life processes affected if they don't have enough

- Elements can be missing from soil if used up nu a previous crop

- Farmers use fertilisers to replace missing elements or provide more of them

- Increases crop yield


What are pesticides, how are they used, advantages and disadvantages (3)

- Form of chemical pest control

- Often poisonous to humans, used carefully to keep amount of pesticide in food below a safe level

- Some pesticides also harm other wildlife


What is biological control (3)

- Using other organisms to reduce number of pests

- By encouraging wild organisms or adding new ones

- Helpful organisms could be predators, parasites or disease causing


Give four advantages of using biological control over pesticides (3)

- No need to reapply

- No bioaccumulation

- Lasts longer

- Less harmful to wildlife


Give an example of a potential problem of biological control (2)

- Cane toads introduced to Aus to eat beetles

- Now a major pest as they poison native species that eat them


How do you make yogurt (9)

- Equipment sterilised to kill of any unwanted microorganims

- Milk is pasteurised (heated to 72 degrees for 15 seconds)

- To kill any harmful microorganisms

- Milk's cooled

- Lactobacillus bacteria are added

- Mixture is incubated (heated to 40 degrees) in a fermenter

- Bacteria ferment the lactose sugar in the milk to form lactic acid

- Lactic acid causes milk to clot, and solidify into yogurt

- Flavours added, e.g fruit, colours, yogurt packaged


What liquid are fermenters full of and how does help microorganims (2)

- Culture medium

- Helps microorganisms grow and reproduce


Why is pH monitered in a fermenter (2)

- Kept at optimum level for the microorganisms enzymes' to work efficently

- Rate of reaction and product yield as high as possible


How and why is temperature monitered in a fermenter (3)

- Water cooled jacket makes sure it doesn't get too hot

- Makes sure temperature is kept at an optimum level

- So enzymes don't denature


How and why are microorganims kept in contact with fresh culture medium (3)

- Using paddles that agitate the medium around the vessel

- Increases product yield

- Because microorganisms can always access the nutrients needed for growth


How and why is oxygen added to the fermenter (4)

- Microorganisms need oxygen for respiration

- Added by pumping in sterile air

- Increases product yield

- Because microorganisms can always respire to provide the energy for growth


How and why are vessels sterilised (6)

- Sterilised between uses

- With superheated steam

- Kills unwanted microbes

- Aseptic conditions increases product yield

- Because microorganisms aren't competing with each other

- Product doesn't get contaminated


Name a product that could be produced by a fermenter (2)

- Penicillin

- Insulin



Describe the process of making beer (9)

- Barley germinates for a few days

- Barley malts

- Hops are added to give bitter flavour

- Yeast is added and mixture is incubated

- Fermenting vessels desgined to stop unwanted microorganisms and air getting in

- Different species of yeast can tolerate different levels of alcohol

- Beer is drawn off through a tap

- Sometimes clarifiying agents are added to remove particles and make it clearer

- Beer is pasteurised to kill any yeast left in the beer


Experiment to show the effect of changing temperatuee on respiration of yeast (8)

- Mix together sugar, yeast, distilled water then add mixure to a test tube

- Attach a bung with a tube leading to a second test tube of water

- Place the tube containing yeast mixture in a water bath at 10 degrees

- Leave the tube to warm up for 10 minutes, then count how many bubbles produced in one minute

- Use this to calculate rate of carbon dioxide production

- This gives an idea of respiration rate

- Repeat with water bath at 20, 30, 40 etc

- As temp increases, rate of respiration should increase, until optimum temp


How to make the experiment to show changing temperature affecting respiration of yeast more accurate (2)

- Replace second tube with gas syringe

- Measure the volume of gas produced instead


Why are fish kept in cages (2)

- Stop them using as much energy swimming about

- Cage also protects them from interspecific predation


What diet are fish fed (3)

- Food pellets

- Carefully controlled to maximise the amount of energy they get

- Better the quality of food, quicker and bigger the fish will grow


Why is it important to keep younger fish seperate from bigger fish and provide regular food (2)

- Makes sure the big fish don't eat the smaller ones

- Stop intraspecific predation


What is a disadvantage to fish farming (1)

- More prone to disease and parasites


How are pests controlled in fish farming, and how does this influence other aspects (2)

- Treated with chemical pesticides which kill them

- To avoid pollution from chemical pesticides, biological pest control can be used instead


Name the enzyme that cuts DNA. (1)

Name the enzyme that joins DNA. (1)

Name a vector. (1)

- Restriction enzyme

- Ligase enzyme

- Plasmid/virus


Explain the process of genetic engineering (7)

- DNA you want to insert (e.g gene for human insulin) is cut out with a restriction enzyme

- Vector DNA is cut open using the same restriction enzyme

- Vector DNA and the DNA you're inserting are mixed together with ligase enyzmes

- Ligases join the two pieces of DNA to produce recombinant DNA 

- Recombinant DNA is inserted into other cells, e.g bacteria

- These cells can now use the gene you inserted to make the protein you want 

- E.g bacteria with gene for human insulin can be grown in huge numbers for people with diabetes


Explain the process of micropropagation (9)

- A plant with desirable characteristics is selected to be cloned 

- Explants are taken from the tips of the stems and the side shoots of this plant

- Explants are sterilised to kill any microorganisms

- Explants are placed in a petri dish with nutrient medium

- Medium has all the nutrients needed for the explants to grow, as well as growth hormones

- Cells in the explants divide and grow into a small plant

- Futher explants can be taken from the smaller plant if large quantities are required

- Small plants are taken out the medium and placed in soil and put into greenhouses

- Geneticall identical to original plant, with same desirable characteristics


Explain how dolly the sheep was created (7)

- Nucleas of a sheep's egg cell was removed

- Creating an ennucleated cell

- A diploid nucleas was inserted in its place

- This was a nucleas from a mature udder of a different sheep

- Cell was electric shocked so it started dividing by mitosis, like a normal fertilised egg

- Dividing cell was implanted into the uterus of another sheep to develop until it was ready to be born

- Dolly created, a clone of the sheep that the udder cell came from