Section 9 - Use of Resources Flashcards
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
