Section 9 - Use of Resources Flashcards Preview

Edexcel GCSE Biology > Section 9 - Use of Resources > Flashcards

Flashcards in Section 9 - Use of Resources Deck (42)
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1
Q

What is meant by ‘Selective Breeding’ [1 mark]

A

Breeding plants or animals together to get the best possible offspring

2
Q

Name 3 potential features of selectively bred organisms [3 marks]

A
  • Max yield of meat, milk, grain etc…
  • Good health and disease resistance
  • Fertility
3
Q

Describe the basic process of selective breeding [4 marks]

A
  • 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
4
Q

Explain how selective breeding can increase the meat yield of cows [3 marks]

A

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5
Q

Explain how selective breeding can increase the number of offspring in sheep [2 marks]

A
  • Female sheep (ewes) who produce large numbers of offspring are bred with rams whose mothers had large numbers of offspring
  • Characteristics of having large numbers of offspring is passed onto the next generation
6
Q

Explain how selective breeding can increase crop yield [4 marks]

A
  • Selective breeding can be used to combine two different desirable characteristics
  • Tall wheat plants have a good grain yield but are easily damaged by wind and rain
  • Dwarf wheat plants can resist wind and rain but have a lower yield
  • These wheat plants were cross-bred, resulting in plants which could resist bad weather and had a high grain yield
7
Q

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

A
  • 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
8
Q

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

A
  • Increases rate of photosyenthesis
  • Plants will grow bigger and faster
  • Crop yields will be higher
9
Q

Why do farmers use fertilisers (7)

A
  • 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
10
Q

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

A
  • 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
11
Q

What is biological control (3)

A
  • 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
12
Q

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

A
  • No need to reapply
  • No bioaccumulation
  • Lasts longer
  • Less harmful to wildlife
13
Q

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

A
  • Cane toads introduced to Aus to eat beetles
  • Now a major pest as they poison native species that eat them
14
Q

How do you make yogurt (9)

A
  • 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
15
Q

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

A
  • Culture medium
  • Helps microorganisms grow and reproduce
16
Q

Why is pH monitered in a fermenter (2)

A
  • Kept at optimum level for the microorganisms enzymes’ to work efficently
  • Rate of reaction and product yield as high as possible
17
Q

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

A
  • 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
18
Q

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

A
  • Using paddles that agitate the medium around the vessel
  • Increases product yield
  • Because microorganisms can always access the nutrients needed for growth
19
Q

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

A
  • 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
20
Q

How and why are vessels sterilised (6)

A
  • 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
21
Q

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

A
  • Penicillin
  • Insulin
22
Q
A
23
Q

Describe the process of making beer (9)

A
  • 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
24
Q

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

A
  • 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
25
Q

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

A
  • Replace second tube with gas syringe
  • Measure the volume of gas produced instead
26
Q

Why are fish kept in cages (2)

A
  • Stop them using as much energy swimming about
  • Cage also protects them from interspecific predation
27
Q

What diet are fish fed (3)

A
  • Food pellets
  • Carefully controlled to maximise the amount of energy they get
  • Better the quality of food, quicker and bigger the fish will grow
28
Q

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

A
  • Makes sure the big fish don’t eat the smaller ones
  • Stop intraspecific predation
29
Q

What is a disadvantage to fish farming (1)

A
  • More prone to disease and parasites
30
Q

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

A
  • Treated with chemical pesticides which kill them
  • To avoid pollution from chemical pesticides, biological pest control can be used instead
31
Q

How are sea lice controlled using biological control (2)

A
  • Small fish called a wrasse
  • Eats the lice off the backs of the salmon
32
Q

Advantages of selectivly breeding the fish (2)

A
  • Less agressive
  • Faster growing
33
Q

Features/advantages of farming fish in tanks (4)

A
  • Water can be monitored to check temperature, pH and oxygen level
  • Easy to control how much food is supplied and give exactly the right sort of food
  • Water can be removed and filtered to get rid of waste and fish poo
  • Keeps water clean for fish and avoids pollution wherever the water ends up
34
Q

Outline 2 disadvantages to Cloning [2 marks]

A
  • Cloned animals might not be as healthy (Embryos often don’t develop normally)
  • Cloning is difficult, time-consuming and expensive
35
Q

Outline 2 advantages to Cloning [2 marks]

A
  • Useful genetic characteristics are always passed on (doesn’t always happen with breeding)
  • Animals with suitable organs for transplantation into humans can be genetically engineered and cloned
36
Q

Name the enzyme that cuts DNA. (1)

Name the enzyme that joins DNA. (1)

Name a vector. (1)

A
  • Restriction enzyme
  • Ligase enzyme
  • Plasmid/virus
37
Q

What is transgenic (1)

A
  • Have genes transferred from another species
38
Q

Explain the process of genetic engineering (7)

A
  • 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
39
Q

Examples and advantages of GM plants (6)

A
  • Make crops resistant to insects
  • So farmers don’t have to spray as many pesticides
  • Wildlife that eats the crop isn’t harmed
  • Make them resistant to herbicides
  • So farmers can spray their crops to kill weeds, without damaging the crop itself
  • Both processes increase crop yield
40
Q

Concerns about growing GM crops (2)

A
  • Transplanted genes may get out into the environment, e.g creating super weeds resistant to herbicides
  • GM crops could adversly affect food chains, or even human health
41
Q

Explain the process of micropropagation (9)

A
  • 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
42
Q

Explain how dolly the sheep was created (7)

A
  • 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