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OCR A level biology > Cloning and Biotechnology > Flashcards

Cloning and Biotechnology Flashcards

1
Q

Define clone

A

Offspring which is genetically identical to the parent organism

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2
Q

Define asexual reproduction

A

The generation of new individuals by mitosis to produce clones

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3
Q

Define vegetative propagation

A

The production of plant clones from non-reproductive tissues

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4
Q

Give 4 ways plants naturally clone

A
  • Bulbs
  • Runners
  • Rhizomes
  • Stem tubes
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5
Q

What is ‘taking a cutting’?

A

Removing and planting short sections of stem of a plant in order to produce clones of that plant

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6
Q

How can the success of cuttings be improved?

A
  • Use hormone rooting powder
  • Reduce the number of leaves
  • Cover with a plastic bag for a few days
  • Make an oblique cut in the stem
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7
Q

Give 2 advantages of taking cuttings over seeds

A
  • less time is needed to grow an adult plant
  • gurantees quality of plants as their characteristics are known
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8
Q

Give a disadvantage of taking cuttings over using seeds

A

-lack of genetic variation in offspring

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9
Q

What is micropropagation?

A

The process of producing large numbers of genetically identical offspring from a single plant using tissue culture

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10
Q

Why might micropropagation be used to clone a plant?

A

If a plant:

  • does not readily produce seeds
  • does not respond well to natural cloning
  • is very rare
  • has been genetically modified with difficulty
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11
Q

Where must tissue be taken from in the tissue culture of plants?

A

From the shoot tips or buds

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12
Q

What type of tissue must be used to micropropagate a plant?

A

Meristematic

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13
Q

Define explant

A

The material removed from the plant which is being cloned

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14
Q

Outline the steps in micropropagation of a plant

A
  • Take some tissue from the shoots or roots of a plant
  • Sterilised the sample (using bleach or ethanol)
  • Place the explant in sterile culture medium containing plant hormones which stimulate mitosis
  • Mass of cells (callus) is divided and put into new culture medium which stimulates plantlet growth
  • Plantlets are potted into compost
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15
Q

Why must micropropagation be done under sterile conditions?

A

In order to prevent the plant tissue from becoming contaminated with bacteria or fungi

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16
Q

Give 4 advantages of micropropagation

A
  • allows for rapid production of large numbers of plants
  • provides a reliable way to increase numbers of rare/endangered plants
  • plants can be produced at any time of year
  • GM plants can be produced in large numbers
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17
Q

Give 4 disadvantages of micropropagation

A
  • produces a monoculture
  • expensive and requires skilled workers
  • if source material is infected with a disease, all clones will be
  • explants and plantlets are vulnerable to infection
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18
Q

What is a callus?

A

A mass of undifferentiated cells

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19
Q

Give 3 examples of plants grown by micropropogation

A
  • potatoes
  • sugar cane
  • bananas
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20
Q

Give an example of a plant grown by taking cuttings

A

Sugar Cane

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21
Q

Give an example of natural cloning in vertebrates

A

Monozygotic twins

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22
Q

Give 2 ways in which animals can be artificially clones

A
  • Artificial twinning
  • Somatic cell nuclear transfer
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23
Q

Outline the steps in artificial twinning

A
  • Animal with desirable trait is treated with hormones so she produces more mature ova than usual
  • Mature eggs are removed and fertilised by semen in the lab
  • When totipotent, the embryonic cells are split to produce several small embryos
  • Embryos are then implanted into the womb of surrogate mothers
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24
Q

Why is artificial twinning carried out?

A
  • Greatly increases the number of offspring produced by animals with best genes
  • embryos can be frozen and the success of the animals can be assessed before all embryos are brought to term
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25
Q

Outline the process of somatic cell nuclear transfer

A
  • A nucleus is removed from a somatic cell of an animal
  • A nucleus is removed from an egg cell of a different animal, the somatic cell nucleus is then placed in the enucleated egg cell
  • A mild electric shock fuses the cell and nucleus and they begin dividing
  • Embryo is transferred into a surrogate
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26
Q

Give 4 advantages of somatic cell nuclear transfer

A
  • enables GM embryos to be replicated
  • useful for pharming
  • enables scientists to clone specific animals
  • enables rare, endangered, or extinct animals to be reproduced
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27
Q

Give a disadvantage of somatic cell nuclear transfer

A

It is a very inefficient process, many eggs are used to produce a single clone

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28
Q

Give 3 advantages of animal cloning

A
  • Desirable genetic characteristics are always passed on
  • Infertile animals can be reproduced
  • Can be used to increase the population of an endangered species, helping to preserve biodiversity
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29
Q

Give 2 disadvantages of animal cloning

A
  • many cloned animal embryos fail to develop
  • animals produced by cloning have shortened lifespans
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30
Q

What is pharming?

A

When animals are geneticially modified to produce pharmaceuticals e.g. human proteins produced in milk

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31
Q

What is theraputic cloning?

A

A form of somatic cell nuclear transfer which has the potential to grow replacement organs which will not trigger an immune response

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32
Q

What is biotechnology?

A

The exploitation of biological processes for use in industrial processes

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33
Q

Give 4 reasons why microorganisms are useful for biotechnology

A
  • No welfare issues to consider
  • Can be easily genetically modified
  • Rapid growth rate
  • Conditions for growing and nutrient requirements are relatively cheap
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34
Q

What is indirect food production?

A

When products made by microorganisms are used to make food (i.e. the microorganisms themselves are not eaten)

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35
Q

Give 4 examples of indirect food production by microorganisms

A
  • Brewing beer
  • Baking bread
  • Cheese making
  • Yogurt making
36
Q

What is direct food production?

A

The microorganism itself is eaten as food

37
Q

Give an example of direct food production

A

Quorn is made from a single celled fungus

38
Q

Give 5 advantages of using microorganisms to make food

A
  • Microorganisms can be grown quickly,easily, and cheaply
  • Microorganisms can be grown on unwanted/wast food
  • Products are easy to separate/pure
  • Microorganisms can produce products (such as protein) very quickly
  • Microorganisms can be grown at low temperatures
39
Q

Give 4 disadvantages of using microorganisms to make food

A
  • if conditions are sub-optimal some microorganisms produce toxins
  • downstream processing of products is required
  • Sterile growing conditions are needed which increases cost
  • People dislike the thought of eating microorganisms
40
Q

Define bioremediation

A

The use of microorganisms to break down polluntants and contaminants in soil or water

41
Q

How can genetic modification be used in bioremediation?

A

Scientists are trying to genetically modify bacteria so they can break down contaminants they would not usually encounter e.g. scientists have modified a bacterium to remove mercury from water

42
Q

Which 2 ways can microorganisms be grown in a lab?

A

Microorganisms can be grown by:

  • innoculating broth or
  • innculating agar
43
Q

Outline how to inoculate a nutrient broth

A
  • suspension of bacteria is made
  • known volume is mixed with a sterile nutrient broth
  • flask is stoppered to prevent contamination from air
  • Incubate at a suitable temperature, shaking regularly
44
Q

Outline how to inoculate agar

A
  • inoculating loop is sterilised by heating in a flame
  • loop is dipped in bacterial suspension
  • zig-zag streaks are made across the agar, taking care to keep the agar surface intact
45
Q

What are aseptic techniques?

A

Techniques used to culture microorganisms in sterile conditions so they are not contaminated with unwanted microorganisms

46
Q

Which stage of the standard growth curve does the red line represent?

A

Lag phase

47
Q

What is the lag phase of the standard growth curve?

A
  • Microorganisms are adapting to their new environment
  • They are growing by synthesising enzymes takes time
  • Not yet growing at their maximum rate
48
Q

Which stage of the standard growth curve does the green line represent?

A

Log/exponential phase

49
Q

Which stage of the standard growth curve does the purple line represent?

A

Stationary phase

50
Q

Which stage of the standard growth curve does the blue line represent?

A

Death/decline phase

51
Q

What happens in the log/exponential phase of the standard growth curve?

A
  • Rate of bacterial reproduction is close to or at it’s theoretical maximum
  • sufficient space and nutrients for population, so little competition between individuals
52
Q

What happens in the stationary phase of the standard growth curve?

A
  • Net growth in population is 0
  • Death rate=rate of cell division
  • Nutrient levels decrease and waste products build up
53
Q

What happens in the death/decline phase in the standard growth curve?

A
  • Reproduction has almost ceased
  • Death rate of cells is increasing
  • Food is scarce and waste products are at toxic levels
54
Q

Give 5 factors which limit bacterial growth

A
  • Nutrients avaliable
  • Oxygen levels
  • Temperature
  • Build-up of waste products
  • Change in pH
55
Q

What is batch fermentation?

A

The Microorganisms and nutrients are placed in the bioreactor and not removed until fermentation is complete

56
Q

What is continuous fermentation?

A

When the microorganism is placed in the bioreactor and nutrient medium is added continually whilst culture broth is removed.

57
Q

What kind of metabolite is harvested from a batch culture?

A

Secondary metabolite

58
Q

What kind of metabolite is harvested from a continuous culture?

A

Primary metabolite

59
Q

At what stage in the standard growth model are products harvested from in batch culture?

A

Stationary phase

60
Q

At what stage in the standard growth model are products harvested from in continuous culture?

A

Exponential/log phase

61
Q

Give 2 advantages of batch culture over continuous culture

A
  • The risk of contamination is low
  • Aseptic conditions are easier to maintain as the bioreactor is sterilised when it has been emptied
62
Q

Give an advantage of continuous culture over batch culture

A

The process is more efficient as product is continuously produced

63
Q

What is a primary metabolite?

A

A substance formed as part of normal growth

64
Q

What is a secondary metabolite?

A

A substance not produced as part of normal growth i.e a substance produced when an organism is experiencing stress

65
Q

Does the production of primary metabolites follow the standard growth curve?

A

Yes

66
Q

Does the production of secondary metabolites follow the standard growth curve?

A

No, production begins in stationary phase

67
Q

What is downstream processing?

A

The recovery and purification of biosynthetic products, including the recycling of salvageable components and proper treatment and disposal of waste

68
Q

How do bioreactors maintain ideal growing conditions?

A
  • Cooling jacket prevents bioreactor getting too hot
  • Contains pH, temperature, and Oxygen probes
  • Mixing blades ensure good oxygenation of the nutrients
  • Air entering the bioreactor is sterilised
69
Q

Why are isolate enzymes better than using whole organisms?

A
  • less wasteful
  • more efficient
  • more specific
  • less downstream processinf required
70
Q

Why are extracellular enzymes used more than intracellular enzymes in biotechnology?

A
  • extracellular enzymes are easier to isolate
  • fewer extracellular enzymes are produced so it is easier to isolate them
  • extracellular enzymes are more robust
71
Q

What are immobilised enzymes?

A

Enzymes which are attached to an inert support system over which the substrate can pass and be converted to product

72
Q

Give 4 advantages of using immobilised enzymes

A
  • enzymes are resuable so reduces cost
  • can be easily separated from products, making downstream processing easier
  • Purer product can be formed
  • enzyme stability increased so can work at a higher temperature, increases rate of reaction
  • Enzyme works in changed pH
73
Q

Give 3 disadvantages of using immobilised enzymes

A
  • reduces the efficiency of the enzymes
  • higher initial cost
  • requires more complex reactors
74
Q

What are the 4 methods of immobilisation?

A
  • Ionically bond to solid support e.g. ceramic beads
  • Covalent bond to substances e.g. other enzymes, collagen
  • Entrapment e.g. in gel based polysaccharides or cellulose
  • Membrane separation
75
Q

Give 3 advantages of membrane entrapment of immobilised enzymes

A
  • Relatively small effect on enzyme activity
  • Relatively simple to do
  • Widely applicable to different processes
76
Q

Give a disadvantage of membrane entrapment of immobilised enzymes

A
  • diffusion of substrate to and product from active site can be slow
77
Q

Give an advantage of entrapment of immobilised enzymes

A

Widely applicable to different processes

78
Q

Give 2 disadvantages of entrapment of immobilised enzymes

A
  • May be difficult to entrap
  • diffusion of substrate to and product from active site can be slow
79
Q

Give 2 advantages of covalent/ionic bonding to inorganic carriers for immobilised enzymes

A
  • enzymes very accessible to substrate
  • enzymes strongly bonded so unlikely to be lost
80
Q

Give an advantage of covalent/ionic bonding to inorganic carriers for immobilised enzymes

A

Active site of enzyme may be modified in the process, making it less effective

81
Q

Give 2 advantages of adsorption to inorganic carriers for immoblised enzymes

A
  • can be used for many different processes
  • enzymes are easily accessible
82
Q

Give a disadvantage of adsorption to inorganic carriers for immoblised enzymes

A

Enzymes can be lost from the matrix relatively easily

83
Q

What is the funciton of glucose isomerase?

A

Converts fructose to glucose

84
Q

What is the function of penicillin acylase?

A

Makes semi-synthetic penicillins

85
Q

Give 3 examples of use of immobilised enzymes in biotechnology

A
  • Penicillin acylase
  • Glucose isomerase
  • Lactase

OCR A level biology (44 decks)

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