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genetic modification Flashcards

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1
Q

What is fermentation

A

A process by which MICROORGANISMS break down GLUCOSE to produce ENERGY, which can happen both anaerobically and aerobically

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2
Q

Word equation for fermentation

A

Glucose —-) ethanol + carbon dioxide

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3
Q

Give three examples of microorganisms

A

Virus, bacteria, protoctists

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4
Q

Explain how the conditions are kept anaerobic in beer making

A

Carbon dioxide produced creates froth which prevents oxygen from entering

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5
Q

Explain how conditions are kept anaerobic in wine production

A

A water filled air lock is placed on top
So that it allows carbon dioxide to escape but doesn’t allow oxygen to enter

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6
Q

Explain how beer is made

A

Barley grains left to germinate which activates the enzyme amalyze to break down starch— maltose
Yeast ferments maltose in barley grains by respiring anaerobically, producing alcohol and carbon dioxide

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7
Q

Explain why yeast respire anaerobically during bread making

A

Because the oxygen is all used up as the yeast use it to rapidly reproduce
Thus in order to survive they begin to anaerobically respire

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8
Q

Explain how bread is made

A

1)flour, water dough and yeast are added and kneaded to make the dough
2) the yeast has used up all the oxygen (to reproduce) , thus produces enzymes that break down the flour to produce sugars, which it uses to anaerobically respire
3) this produces ethanol and carbon dioxide, where the carbon dioxide trapped inside the bread causes the bread to rise
4) the bread is baked where the gas bubbles expand and the high temperature kill the yeast, and the ethanol evaporates.

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9
Q

Explain how to make yogurt (8)

A

1)sterilize all equipment to prevent microorganisms from growing and to prevent chemical contamination
2) Pasteurize the milk at 85-95degrees for 15 seconds , to prevent harmful microorganisms from growing which can slow down the growth of the yogurt as they will compete with each other, and could spoil the taste
3)Homogenize the milk, so that the flat globules are distributed
4)Cool the milk at 40-45
5)inoculate with culture of bacteria (lactobaccilus bulgaricus) and incubate for a few hours
The bacteria ferment the lactose(milk sugars) into lactic acid which:
-prevents the growth of harmful microorganism’s so perseveres the nutrients in the milk
-and coagulates the milk.
-The PH also denatures enzymes in milk proteins, causing them to turn into semi-solids.
-gradually halts the reproduction of yeast
6)the yogurt is cooled to 5 degrees and stirred
7)flavorings and colorings can be added before packing

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10
Q

Explain what effects lactobaccilus has on yogurt production (3)

A

ferments lactose into lactic acid which,
-this low ph prevents other harmful microorganisms which preserves the nutrients
-coagulates the milk to make it thicken
-denatures milk proteins so that they turn into semi-solids

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11
Q

Explain why milk is pasteurized in yogurt production

A

-to kill harmful microorganisms which slow the production of yogurt as they create competition with lactobacillus
-so that other microorganisms do not spoil the milk

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12
Q

Why does lactobacillus stop reproducing eventually in yogurt production?

A

-because the lactic acid has a low pH which gradually reduces their reproduction

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13
Q

Meaning of biotechnology

A

The use of microorganisms to produce us useful products for humans

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14
Q

Give two reasons why microorganisms are useful for biotechnology

A

1)Because they use an external food source to produce waste products, which can be used and useful for humans
2)there are no moral or ethical concerns

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15
Q

What is the function of the steam Inlet in a fermenter(2)

A

To sterilize the fermenter, inorder to prevent the growth of harmful microorganisms:
-because if microorganisms enter they can compete with the cultured microorganisms, reducing their yield efficiency
-to prevent contamination, as the microorganisms could release other waste products

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16
Q

What is the function of the water jacket surrounding a fermenter(2)

A

-Continuously circulates cool water around, to prevent the culture from overheating at to keep it at its optimum for enzymes to function for its growth
-Because fermentation releases heat

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17
Q

What is the function of the paddles in a fermenter

A

-Distributes the heat to keep enzymes of the microorganisms at optimum temperature for growth
-keeps the microorganisms In exposure to the nutrients of the culture for optimum growth

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18
Q

What is the function of the air inlet in a fermenter

A

So microorganisms need to respire aerobically, so it gives them access to oxygen at all times

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19
Q

Why is the air inlet filtered in a fermenter?

A

To prevent the air from becoming contaminated

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20
Q

Which type of materials are fermenters made of and why?

A

Made of materials that do not corrode such as stainless steel, because many microorganisms produce acidic waste products

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21
Q

Why can wine not be made with an alcohol concentration higher than 15%

A

When yeast respire anaerobically they produce ethanol, but high amounts of ethanol inhibit the growth of yeast
Thus as more ethanol is produced, it kills the yeast

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22
Q

Explain why the water is boiled in the experiment to investigate anaerobic respiration of yeast with a test tube

A

To ensure that any air present in the water is removed

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23
Q

What color does hydrogen carbonate indicator turn in the presence of carbon dioxide

A

From orange—) yellow

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24
Q

Describe how you could measure the rate of reaction, of anaerobic respiration of yeast, using hydrogen carbonate indicator and lime water

A

With lime water, you can count the number of bubbles produced
With hydrogen carbonate indicator, you can time how long it takes for it to change colour to yellow

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25
Q

Give a more accurate way of measuring the rate of reaction of anaerobic respiration in yeast, instead of counting bubbles or seeing how long hydrogen carbonate takes to change colour

A

Measure the volume of gas collected in a gas syringe

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26
Q

Give for ways in which humans make demands on the environment:

A

1)make space for living and for waste
2)use fuel for powering vehicles and heating homes
3)food to sustain an ever growing population
4)materials to build homes with

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27
Q

Give three ions + magnesium that plants need and their functions

A

Nitrates—) needed to make amino acids for proteins which aid in cell growth
Phosphates—) needed to make DNA and cell membranes
Potassium—-) needed to help enzymes for respiration and photosynthesis
Magnesium—) makes chlorophyll which is needed for photosynthesis

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28
Q

Explain for each of the three +magnesium important ions that a plant needs, what happens if it lacks in them

A

Nitrates—-) poor plant growth and yellowed leaves
Phosphates—-) poor root growth and purple or discolored leaves
Potassium—-) poor flower or fruit growth with brown spots
Magnesium—) yellowed leaves

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29
Q

Give three ways that a farmer can maximize crop yield in terms of soil

A

1)soil structure—) can plough to break apart compacted soil, so that it has better drainage and aeration for better mineral uptake
2)soil ph—-) can add like for example to acidic salts because if salt is too acidic this can reduce mineral uptake
3)control amount of ions—-) add fertilizers so that extra minerals are taken up for better crop growth

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30
Q

Explain why a farmer may want to plough his field

A

This breaks apart compacted soil
so that there is more aeration and drainage
Thus better mineral uptake and better crop growth

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31
Q

Why are acidic soils not good

A

Because they reduce the uptake of minerals

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32
Q

What is hydroponics

A

Growing plants without soil

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33
Q

What are the benefits of using fossil fuels for heating in a green house?

A

They produce carbon dioxide and water vapour
Where the carbon dioxide is crucial for photosynthesis
And the water vapour reduces water loss by transpiration

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34
Q

Explain how greenhouses are heated naturally by the greenhouse effect

A

Short wave infrared radiation enters
And is re-radiated back out as long wave infrared radiation
But cannot escape through the glass, so heats up the green house

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35
Q

What are the three main factors that limit the rate of photosynthesis

A

-temperature
-light intensity
-carbon dioxide

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36
Q

Give four ways greenhouses can optimize photosynthesis

A

1)can control heat as it absorb heat because of the green house effect, keeping at the optimum temperature, and in the winter can use paraffin heaters
2) can control carbon dioxide levels using a paraffin heater
3) can control the light intensity, where even at night light can be switched on to optimize time for onto synthesis
4)keeps in an enclosed space to protect from pests

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37
Q

Give two examples of organic fertilizers

A

Manure
Compost

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38
Q

Explain why organic fertilizers are not as effective at restoring nitrogen to the soil as inorganic fertilizers are

A

Because they are made of faaces and so only contain a portion of nitrogen (because it’s a waste product)

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39
Q

Explain why organic fertilizers are better at improving soil structure, compared to inorganic fertilizers

A

Inorganic fertilizers do not contain decaying matter, which is an essential to soil

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40
Q

What is one way of returning nitrogen back to the soil apart form using fertilizers?

A

Grow a legume crop which contains nitrogen fixing bacteria

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41
Q

What is a pest

A

An organism that reduces the yield of a crop

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42
Q

What do molluscicides kill

A

Snails and slugs

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43
Q

Give four disadvantages of pesticide

A

1)can create resistance where they become useless
2)can build up in the fatty tissues of organisms as bio accumulation, and can become more concentrated throughout the food chain, called bio magnification
3) are slow to decompose so persitant in the environment
4) can kill other other unharmful organisms

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44
Q

Explain how bio accumulation works in pesticides

A

Pesticides are soluble fats so when a herbivore eats a plant with pesticide on it,
This is absorbed into the fatty tissue instead of being broken down
So the carnivore that eats this also has pesticide build up in their fatty tissues

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45
Q

Explain how pesticides such as DDT spread around the world

A

Pesticides are persistent and so stay sprayed for long periods of time
And winds can carry them with them

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46
Q

Some farmers control pests by instead of growing the same type of crops all at the same time of year, they grow different crops at different times.
Explain how this reduces damage by pests

A

Pests usually have a preference for a specific type of crop, so if their crop is not there then they are likely to leave

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47
Q

Give four criteria that an idea, pesticide should have

A

Should be biodegradable
Should be easy to apply
Should only target the specific organism
should be safe to transport and store

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48
Q

Give an example of a pest for tomatoes

A

Whiteflies

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49
Q

Explain how when using biological control, pests can never fully b eliminated

A

Because if the biological control agent did kill all the pests, it itself would die out because it would have no food supply

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50
Q

Give four examples of biological control agents

A

-natural predator
-parasite
-pheromone(natural chemicals that attract mates)
-sterile males(so that no offspring can be born)

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51
Q

Give four disadvantges of biological control

A

-doesn’t kill all the pests
-acts very slowly
-could become a pest itself
-may not be able to adapt to new environments or may move out itself

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52
Q

Two Advantages of using chemical pesticides

A

-quick and easy
-wipe out entire population

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53
Q

4 Advantages of biological control

A

Does not create resistance
Does not need to be reapplied because organism can keep reproducing
Can be specific to organism
Does not lead to bio accumulation in food chains

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54
Q

Give six advantages of fish farming

A

-can control the water quality ,by filtering waste products and harmful bacteria, which can reduce disease and thus increase chance of survival. This also maintains high levels of oxygen so increased aerobic respiration
-can control diet and frequency of feeding by giving food pellets with high nutrients to increase biomass, and can control how often they eat to prevent overeating and other fish eating them.
-can control intraspecific predation by keeping them separated by age and size to prevent fish eating each other, and can control inter specific predation by keeping different species in different tanks/nets
-can use selective breeding by spreading by gender so farmer can control number of fish produced. And can produce fish that are less aggressive.
-by keeping in confinement, you can reduce energy loss as less energy needed to swim around
-can reduce disease by using antibiotics
-

55
Q

Give three disadvantges of fish farming

A

-pesticides used and food pellets can pollute waters and cause eutrophication, which can kill other species.
-use of antibiotics could create antibiotic resistance in bacteria
-close confinement increases the spread of disease

56
Q

Give the following in order of biggest to smallest(gene, nucleus, DNA, chromosome)

A

Nucleus
Chromosome
DNA
Gene

57
Q

Give three examples of types of proteins

A

A hormone such as Insulin
A structural protein such as Collagen
An enzyme that controls a particle ur reaction such as amalyse

58
Q

What is a transgenic organism

A

An organism that has GENES inserted in it from an organism of ANOTHER SPECIES

59
Q

What is recombinant DNA

A

DNA that has the gene from another species in it

60
Q

What are the two types of cut that restriction enzymes can make

A

Blunt cut and staggering cut

61
Q

Why does DNA cut with a staggering cut have “sticky ends”

A

Because it has exposed dna bases which are more easily joined with ligaze enzymes

62
Q

What are restriction enzymes and what do they do

A

Enzymes that cut dna molecules at specific points, where different restriction enzymes cut DNA at different points
And are used to cut out genes of DNA

63
Q

What are ligases

A

Enzymes that join together two cut pieces of DNA

64
Q

What is the vector in producing transgenic bacteria

A

The plasmids in the bacteria

65
Q

Give the process of making insulin producing bacteria

A

-Remove the plasmid from the bacteria
-Then use restriction enzymes to cut it open
-then cut out DNA (so the gene for insulin) in a human, using the same restriction enzyme
-Then use a ligase enzyme to join the plasmid and the insulin gene together
-to form a recombinant DNA
-insert the recombinant DNA back into the bacteria and incubate in a fermenter to grow
-the bacteria will reproduce using binary fission and the recombinant DNA, to produce insulin

66
Q

Why is the same restriction enzyme used for both the plasmid and the insulin gene when producing genetically modified bacteria

A

Because this means that they both have the same sticky ends and so will join togther using ligase enzymes

67
Q

Explain how viruses can be used to genetically modify a bacterium

A

Virus is a vector
Foreign DNA is inserted into the virus
Which injects this DNA, aswell as it’s own into the bacterium
This DNA is taken up by the bacteria DNA

68
Q

Give the name of a virus that is used as a vector for transgenic bacterium

A

Bacteriophage

69
Q

Give three reasons why bacteria are good for genetic engineering

A

1) there are no moral or ethical concerns over using them
2)they contain plasmids, which are separate from the main chromosomes of the bacterium, so are easy to use and replace
3) they contain the same genetic code as the organism you are using, so can easily be read and can produce the same enzymes

70
Q

Give six uses of genetically modified bacteria

A

-to produce human insulin
-to increase cattle milk yield and muscle for meat
-to produce human growth hormone
-used as human vaccines
-used in food production to convert glucose into sucrose
-Used as washing powder

71
Q

Give on disadvantage of giving BST ( bovine growth hormone) to cattle

A

They need to be fed more food

72
Q

Why can plants not be genetically modified in the same way that a bacterium can be

A

Because a bacterium has only one cell which receives the new gene, but plants have many cells which would have to receive it

73
Q

Why should multicellular organisms be genetically modified at an early stage, and give the stage it should be done at in animals

A

So that all of the cells receive the transferred gene, for example in an animal you would do it when they are in the embryo stage

74
Q

Explain one way that genetically modified crops can be produced

A

1)Section of DNA is cut out from another species using restriction enzymes
2)plasmid from bacterium is cut out using the same restriction enzymes
3) ligases join these together to form recombinant DNA
4)this recombinant DNA is dissolved into a liquid, and leaf discs absorb the plasmid
5) these leaf discs are cultivated on a nutrient medium
6)these grow into plants with the new foreign gene

75
Q

What is a vector

A

The means of transferring a gene

76
Q

How does the “gene gun” work

A

It fires a bullet coated with the DNA of the forge in desired gene, which is the absorbed by the plant tissue

77
Q

Give six advantages of genetically modified crops

A

1)can be insect resistant, so that farmers can apply less pesticides so less damage to the environment
2)can be herbicide resistant, so farmers can spray as much as they need to for weeds, without affecting the crop itself, increasing crop yield
3)can be virus resistant, increasing crop yield and food security
4)can have longer shelf life
5)can have enhanced flavor and greater consumer attractiveness
6)can have greater nutritional value
7)can make them hardier, so for example can thrive in arid or harsh conditions

78
Q

Give four disadvantges of genetically modified crops

A

1)reduced bio diversity
2) potential harm to human health as could trigger allergic reactions
3)risk of outcrossing because genes for herbicide resistance for example could be transferred to weeds by pollination
4)increased cost for seeds means farmers in poorer communities can not compete with larger farms

79
Q

How could golden rice be good for developing countries

A

Contains the gene to make beta carotene, which can be converted to vitamin A, which can prevent blindness

80
Q

How could GMO plants be used as a vaccine for humans

A

They could produce the antigens for a disease, and thus trigger antibodies in the body to create immunity

81
Q

Why could GMO plants be a better vaccine than traditional vaccines that contain viruses

A

Because there is a risk that the virus could be infectious, but with GMO plants there is no risk because they only contains the antigens of the disease

82
Q

What could be an advantage of producing GMO crops that allow nitrogen fixing bacteria to grow on them, that grow in infertile soils

A

Would not need to use fertilizers that release nitrates as nitrogen fixing bacteria could simply obtain nitrogen from the air, which could be converted to proteins for growth

83
Q

Explain how the shortage of donor organisms could be resolved with xenotransplantation(transplanting organs from other animals into humans)

A

Because by using genetic modification, the animal could have some similar genes as the human that code for the antigens and so would be less likely to be rejected from the body

84
Q

Give four reasons to selectively breed plants

A

To increase crop yield
To make hardier so that they can survive harsher climates
To give a greater balance of nutrients
To make resistant to diseases

85
Q

Give four reasons to selectively breed animals

A

To produce more offspring
To produce Greater quantity of milk, eggs or meat production
To make increased resistance to diseases

86
Q

Give two examples of ex plants that you could take

A

Side shoots or tip of the stem

87
Q

Explain how plants can be cloned by taking cuttings (3)

A

1)take cutting of the parent plant
2)dip in root powder to stimulate root growth
3) once roots and shoots have grown, place in soil in a greenhouse for optimum environments

88
Q

Explain how micropropogation can be used for cloning plants (6)

A

1)select plant with the desire characteristics and take an ex plant from it with a scalpel, so a small piece of the plant
2) sterilize to kill harmful microorganisms
3)grow them in vitro, so place in a Petri dish with Agar jelly with nutrients for growth and growth hormone auxin
4)the cells will divide by mitosis until a plant is formed which will be a clone to the regional plant, so genetically identical
5) if more plants are required, then take more ex plants
6) place in soil in a pot in a greenhouse for optimum environment for growth, such as control the light intensity or the temperature

89
Q

Give four advantages of cloning plants

A

1)can produce genetically identical plants that all have the same gene quickly and in large numbers
2)can be stored easily, because can be kept in cold temperatures at early stages and then developed when required
3) can be be grown all year round
4)can be used to preserve rare species of plants

90
Q

Give an example of a crop that has been selectively bred many times and what it has produced

A

Brassica to produce for example cauliflower, cabbage and broccoli

91
Q

What is the disadvantage of selectively breeding crops (3

A

Leads to inbreeding, which reduces the gene pool,
so more vulnerable to diseases and
more likely to inherit genetic diseases

92
Q

Explain how to selectively breed plants (4)

A

1)Human chooses two organisms
2)that have the desired characteristics, SUCH AS a flowering plant or a crop with high yield
2)two plants are cross-bred, where the pollen from one plant is transferred to the stigma of the other plant
3)the offspring will have the same inherited characteristics, which will have to be cross bred again
4)repeat process over generations

93
Q

Explain how an animal can be cloned using adult cell cloning

A

1)remove the nucleus of an egg cell(a haploid) from a sheep to form an enucleated cell
2)remove the nucleus of an adult cell(a diploid) from another sheep that you want to clone, and reinsert it into the enucleated egg to form a zygote
3)stimulate the cell with electricity so that it divides by mitosis to form an embryo
4)implant the embryo into the uterus of a surrogate mother
5)the offspring born should be a clone of the sheep who’s diploid cell’s nucleus was removed and reinserted.

94
Q

Why can an egg cell not be used by itself to form a clone

A

Because it only contains 23 chromosomes which is half the number of chromosomes in normal body cells

95
Q

Why can a haploid cell not be used for cloning

A

Because it is too specialized to form a new individual

96
Q

How was dolly the sheep cloned

A

A mammary gland cell was fused with an enucleated egg cell from a donor sheep,
and then fused together with electricity , which didvided by mitosis
where the embryo was implanted into the uterus of a surrogate mother to develop into a clone

97
Q

Give three advantages of mircropropogation

A

-Can produce disease free plants
-produces large amount sun short period of time
-can be used to preserve endangered species

98
Q

Give three disadvantages of micropropogation

A

1)aseptic conditions are required
2)expensive process
3) requires trained personnel and sterile laboratory equipment

99
Q

What is biological control and give an example

A

Using one species to control the population size of another
An example would be using ladybirds to control aphid numbers

100
Q

What is a gene

A

A small section of dna that codes for a specific protein for a desired characteristic

101
Q

What is a clone

A

An organism that is genetically identical to its parent

102
Q

What are two advantages of using a clone for a donor

A

Will have no issues with being rejected
No issues with shortage because will always be available

103
Q

Suggest what is meant by the term genetic modification and why a farmer may want to produce a genetically modified crop (3)

A

When you transfer a gene from a different species to another organism of another species to the next to greate a transgenic organism
They may want to, to either increase crop yield,
Or to produce disease resistanct crops

104
Q

Suggest how you could control the moisture in a green house

A

Fogging greenhouse

105
Q

Give four reasons why fish farming is being preferred over traditional farming

A

1)you can control the size and mass of fish, by controlling protein given to them eg
2)the fisherman is safer
3)you can reduce over fishing
4)you can produce larger numbers of fish

106
Q

What is a weed(2)

A

An unwanted plant which is unwanted because for example it creates competition with the plant for nutrients or mineral for example

107
Q

Give three reasons why embryo cloning is better than selective breeding

A

1)two parents are not needed only a female
2)a much quicker process
3)the offspring will be genetically identical, so will all have exactly the same characteristics

108
Q

Suggest why minerals have different effects if rice grown low land and rice grown up land

A

Because there may be different types of soil in each area

109
Q

Suggest how you can measure the dry mass of a crop that is fresh (so with some water in it)

A

Measure the mass before on a scale
Then heat in an oven and keep measuring the mass until it stays the same
The measure again to find the dry mass

110
Q

Explain why when measuring and comparing crop yields you often use a percentage rather than the have actual value

A

Because it allows for better comparison,
Because for example each type of crop may have started with a different mass which could affect the amount of yield it started with

111
Q

Suggest why,
1)reducing the number of insects affects the growth of a crop,
2)And why reducing the number of weeds affects the growth of a crop

A

1)Reducing the number of insects means that less crop is eaten by them, thus more crop yield produced
2)reducing the number of weeds means, less completion for nutrients and mineral such as potassium for example, thus more photosynthesis

112
Q

Explain why faeces are good for crop growth

A

Because microorganisms decompose them
So thus there are more minerals available to the plant such as potassium
So thus there is more optimum conditions for photosynthesis

113
Q

Suggest how increasing the oxygen content of the soil helps crops to grow more

A

Because the roots require oxygen for respiration, and so will produce more ATP with more oxygen
And ATP is used for active transport
Thus there is more mineral uptake such as the uptake of nitrates for growth

114
Q

Give one reason to Explain why there may be an increase in algae in a fish farm,
and then give two solutions for it

A

Because there may be large amounts of sewage like fish faeces present, which contain many nutrients and minerals for algae growth such as nitrates

Solution is that you could use a pump to filter the water and remove the sewage,
Or then do not over feed the fish so that they produce less waste

115
Q

Give three ways how oxygen levels can be maintained in a fish farm

A

Be using a pump
By removing sewage
By implanting water plants

116
Q

Give two ways how predation can be avoided in a fish farm

A
  • separate fish by species and size
    -cover with a net to prevent predators such as birds from entering
117
Q

Give two ways disease can be prevented in a fish farm

A

-use antibiotics
-keep in small number so that disease doesn’t spread

118
Q

How does removing sewage help to maintain water quality

A

Because there is less bacteria who decompose using aerobic respiration, thus using oxygen
So oxygen levels are maintained

119
Q

How do antibiotics help to maintain water quality (2)

A

Because it kills pathogens
So there is less disease

120
Q

How does manure help with plant growth (4)

A

1)bacteria decomposes it
To produce nutrients and minerals such as nitrates to make amino acids for proteins for growth
Which plant absorbs through active transport using ATO
And because bacteria decomposes aerobically, are on dioxide is released
Which is good for photosynthesis

121
Q

Suggest why in a fish farm, food is given in small amounts but frequently (3)

A

To ensure all the food is eaten
And so that there is less waste
Which can leads to eutrophication for example

122
Q

Give an example of a selectively bred crop plant, and what the desired characteristic was and why

A

Wheat
With shorter stems
So that it grows much quicker and does not fall over, thus obtaining higher yield

123
Q

Explain how you can produce a transgenic animal

A

1)take fertilized eggs from an animal
2)and inject genes with the desired characteristics into them
3) the egg will take up the gene into one of its chromosome
4)this develops into embryos which are implanted inside a surrogate mothers uterus (and do offspring born are clones of the embryo)

124
Q

Give an example of something that a cloned transgenic animal can produce and what it can be used for to cure

A

Can produce the protein AAT
Which can cure cystic fibrosis

125
Q

Why is it a benefit for a cow to be able to digest cellulose

A

Because it contains glucose
Which can be used for more respiration
Thus more milk production for example

126
Q

Give an example of a transgenic organism and what it does

A

Golden rice
Which makes beta-carotene, which is converted to vitamin A
To prevent blindness

127
Q

How can faeces affect the growth of fish on a fish farm?

A

Microorganisms decompose the faeces
And whilst doing so they aerobically respire
Thus depleting oxygen levels of the water
Thus less aerobic respiration can be done by the fish

128
Q

What is the main word equation used in making bread
What is the main word equation used in yogurt production

A

-glucose—)ethanol + carbon dioxide
-lactose—-) lactic acid

129
Q

Give two ways in which organic fertilizers are better than chemical fertilizers

A

1)leads to less eutrophication because less leaching because they are not insoluble like chemical fertilizers
2)contains organic material so improves soil structure

130
Q

Suggest how explants are removed and transferred to Petri dish

A

Removed with a sterilized scalpel
And transferred with sterilized tweezers

131
Q

Give three reasons why cloning animals is an advantage

A

-all would be genetically identical so all would contain the same gene
-can produce large numbers of the animal
-if using genetically modified animal, would only have to perform genetic modification once
(In the markscheme)

-can preserve endangered species

132
Q

After being pasteurized, why is yogurt cooled to 45 degrees (3)

A

To prevent killing the lactobacillus bulgaricus , because the high temperatures will denature the enzymes,
So cooling the yogurt keeps the enzymes at an optimum temperature

133
Q

Explain why a farmer would want to grow legumes in the soil before growing cereal plants

A

Because the legumes have nitrogen fixing bacteria in their root nodules
Which convert atmospheric nitrogen to ammonium
Which the plant uses for amino acids to make proteins for growth
And then the legumes eventually are decomposed by microorganisms
To release minerals and nutrients

134
Q

If the PH is too acidic in a fermentor, how can this affect the production of human insulin (4)

A

-acidic contains are not the optimum PH,
-and acidic conditions can denture the enzymes of the bacteria as it destroys the active site
-therefore the bacteria is killed
-and so no insulin can be produced

biology (16 decks)

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