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A2 Biology OCR > 6.4 > Flashcards

6.4 Flashcards

1
Q

What are clones?

A

Genetically identical organisms or cells

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2
Q

Advantages of natural cloning

A
  • cloning is relatively rapid so population can increase fairly quickly
  • reproduction can be carried out even if there is only one parent, where sexual reproduction can’t happen
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3
Q

Disadvantages of natural cloning

A
  • offspring may become overcrowded
  • There will be no genetic diversity (apart from that caused by mutations in DNA replication)
  • the population shows little variation
  • an environmental change means the whole population is affected
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4
Q

What is vegetative propagation

A

plant clones being created from vegetative parts of a plant

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5
Q

what are 4 kinds of stems plants can produce clones

A
  • Runners
  • Stolons
  • rhizomes
  • suckers
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6
Q

what are runners and stolons

A

horizontal stems that grow on the surface of the ground that will produce a clone

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7
Q

What are rhizomes

A

horizontal stems the grow beneath the ground

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8
Q

what are suckers

A

new stems that grow from the

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9
Q

what are bulbs

A

fleshy underground stem from which grow leaves and they also have an apical bud that allows flowers to grow in spring

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10
Q

What are corms

A

similar to bulb but solid not fleshy

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11
Q

What plant reproduces asexually from its leaves

A

the kalanchoe

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12
Q

when does cloning happen in animals

A

when the zygote splits to become two separate cells resulting in twins

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13
Q

what are 3 ways of artificially cloning plants

A

cuttings
tissue culture
micropropagation

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14
Q

how do clone a plant through cuttings

A

to make a cutting, a stem is cut between two leafy joints (nodes) and may be dipped in rooting hormone and then is put in moist soil.
May also be useful to remove the bark from the end of the stem so pant produces a callus.

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15
Q

what other parts of the plant can cuttings be made

A
  • root cuttings, where a section of the root is buried below the soil surface and so it produces new shoots
  • scion cuttings, which are dormant woody twigs
  • leaf cuttings, where a leaf is placed in the soil and it produces new stems
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16
Q

what is tissue culture

A

is a series of techniques used to grow plants from samples in a nutrient medium on sterile conditions

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17
Q

what is micropropagation

A

growing large numbers of new plants from meristem tissue taken from a sample plant

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18
Q

what are the steps of microporopagation

A
  • meristem tissue taken, these are called explants
  • explants are steralised using alcohol
  • explants placed on sterile growth medium contains hormones
  • a callus forms and it is divided into a large number of small clumps of undifferentitated cells
  • small clumps of cells moved to different growth medium and small plantlets are formed
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19
Q

advantages of artificial cloning

A
  • cloning is faster than growing from seeds
  • cloning can happen where sexual reproduction can’t
  • means plants are genetical identical so show desirable charictaristics
  • all plants grown are uniform so easier to harvest
  • using meristem as an explant ensures new plants are free from viruses
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20
Q

disadvantages of artificial cloning

A
  • tissue culture is labour intensive
  • expensive
  • no genetic variation
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21
Q

what are totipotent cells

A

the can differentitate into any cells

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22
Q

what is embryo twinning/ splitting

A

splitting an embryo to create two genetically identical embryos

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23
Q

steps of embryo twinning/ splitting

A
  • a zygote is created in IVF
  • zygote is allowed to divide by mitosis to form a small ball of cells
  • cells are seperated and allowed to continue dividing
  • each small mass of cells is placed into the uterus of a surrogate mother
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24
Q

steps of somatic nuclear cell transfer

A
  • an egg cell is obtained and its nucleus is removed
  • a body cell of the adult to be cloned is obtained(called somatic cell)
  • the somatic cell is fused with the egg cell by an electric shock
  • electric shock also causes cell to start developing as if it had been fertilised
  • cell undergoes mitosis
  • embryo is placed in surragote mother
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25
Q

what is therapeutic cloning

A

new tissue and organs that can be grown as replacement parts for people who are not well

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26
Q

arguments for artificial cloning

A
  • can produce a whole herd of animals with high yeild
  • testing medical drugs on cloned cells and tissues avoids using them on animals or people for testing
  • individuals form an endangered species can be cloned to increase numbers
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27
Q

arguments against artificial cloning

A

-cloned animals may be less healthy

-very expensive for a low success rate

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28
Q

advantages of using microorganisms in biotechnology

A
  • cheap
  • easy to grow
  • reproduce quickly
  • can be fed by-products from other food industires
  • production can take place anywhere as not dependent on climate
  • fewer ethical issues
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29
Q

how is biotechnology used in production of yogurt

A

fermented milk
bacteria convert lactose to lactic acid
the acidity denatures proteins causing coagulation

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30
Q

how is biotechnology used in the production of cheese

A
  • bacteria converts lactose to lactic acid
  • acidified milk is mixed with rennin
  • rennin coagulates casein in presence of calcium ions
  • curd forms that is pressed into moulds
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31
Q

how is biotechnology used in baking

A
  • ingredients are mixed together to form dough
  • the yeast in the dough respires anaerobically producing carbon dioxide bubbles causing dough to rise
  • the dough is baked and any alcohol evaporates
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32
Q

how is biotechnology used in the production of alcoholic bevrages

A

wine
-yeast on surface of grapes respires anaerobically using sugar in crushed grapes

beer
-malting grains convert starch to maltose which is respired by yeast.

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33
Q

disadvantages of using microorganisms

A
  • some people may not want to eat food grown on waste
  • protein does not have the same taste texture as traditional protein
  • risk of infection of proteins
  • proteins have to be purified
34
Q

how do you scale up the production of drugs

A

fermenters

35
Q

what conditions need to be controlled to produce the greatest yield of drugs

A
  • temperature
  • nutrients available
  • oxygen availability
  • pH
  • concentration of product
36
Q

what are primary metabolites

A

products that are produced when microorganisms are growing and metabolising normally

37
Q

how often can primary metabolites be collected

A

can be collected continuously from brroth

38
Q

what is continuous culture

A

removing some of the broth regularly to remove the product and cells otherwise population becomes to dense

39
Q

what are secondary metabolites

A

products that are produce when the cells are placed under high stress levels like having limited nutrient availability

40
Q

what is batch culture

A

when the cells are set up with limited variables and time in the feremnter and it is emptied to collect the secondary metabolites

41
Q

what is asepsis

A

ensuring sterile conditions are maintained

42
Q

why is asepsis essential

A

the nutreint medium the cells grow on can support unwanted growth of other microorganisms

43
Q

what can these unwanted microorganisms do in the fermenter

A

reduce the yeild of product

spoil the product

produce toxic chemiclas

compete with the culture

44
Q

where is penicillin mass produced

A

fermenter

45
Q

what type of metabolite is penicillin

A

secondary metabolite so manufactured through batch culture

46
Q

how is penicillin produced

A
  • fermenter is left to run for 8 days then culture if filtered to remove cells
  • antibiotic is precipitated as crystals by addition of potassium compounds

-antibiotic is mixed with inert substances
and prepared as tablets or syrups

47
Q

what is bioremediation

A

the use of microorganisms to clean the soil on polluted sited by converting the toxic pollutants to less harmful substances

48
Q

what does bioremediation involve

A
  • stimulating the growth of microorganisms that use contaminants as a source of food.
  • need water, suitable temperature, suitable pH
49
Q

advantages of bioremedation

A
  • uses natural systems
  • less labour needed
  • treatment in situ
  • few waste product
  • less risk of exposure to clean-up personal of toxic chemicals
50
Q

disadvantage of bioremedation

A

heavy metals can not be treated

51
Q

what are they 2 types of common growth mediums microorganisms are grown on

A
  • broth (soup like liquid)

- agar which is melted into petri dishes

52
Q

what are 6 aspectic techniques that reduce the likelihood of contaminating medium with unwanted microorganisms

A
  • wash hands
  • disinfect working area
  • have a Bunsen burner to heat air around work space to prevent air-borne microorganisms settling and make sterile air
  • as you open a bottle pass its neck over the flame to prevent microorganisms in air from entering
  • don not lift lid of petri dish completly
  • any metal/glass equipment should also be passed through flame before being allowed to come into contact with desired microorganisms
53
Q

what are the 3 steps of growing microorganisms on agar plates

A
  • sterilisation
  • inoculation
  • incubation
54
Q

how to sterilise agar

A

agar medium is heated in an autoclave at 121 degrees for 15 minutes which kills any living microorganisms and then it is poured into petri dishes once cooled and then lid is placed

55
Q

what is inoculation

A

inoculation is the introduction of microorganisms to the sterile medium

56
Q

what are 4 ways of inoculation

A
  • streaking, a wire loop transfers a small amount of liquid onto agar and it is spread out
  • seeding, a sterile pipette can be used to transfer a small amount of the liquid onto agar

-spreading, a glass spreader can be used
to spread the liquid drop across the agar

  • a cotton bud can collect microorganisms from one surface and transfer them to another
57
Q

how are petri dishes incubated

A

petri dish is placed upside down in an incubator to prevent condensation drops falling on agar and it drying out to quick, dish should not be sealed completely as this could result in potentially pathogenic anaerobic microorganisms

58
Q

what is a closed culture

A

a population in which all conditions are set at the start and there is no exchange with the external environment

59
Q

what are immobilised enezymes

A

an enzyme that held in place and not free to diffuse through the solution

60
Q

advantages of immobilising enzymes

A
  • enzymes do not mix with product so extraction is cheaper
  • enzyme can be easily reused
  • continuous processes are made easier
  • enzymes protected from extreme conditions as they are surrounded by immobilising matrix
61
Q

disadvantages of immobilising enzymes

A
  • expensive

- immobilised enzymes are less active so rate of reaction is slower

62
Q

what are 4 methods used to immobilise enzymes

A
  • adsorption
  • covalent bonding
  • entrapment
  • membrane seperation
63
Q

how does adsorption work

A

enzymes are bounded to a surface like clay, porous carbon, resins or glass beads
by hydrophobic and ionic bonds

64
Q

advantages of adsorption

A

cheap

65
Q

disadvantages of adsorption

A
  • hydrophobic and ionic bonds are weaker so there is a chance of them breaking and enzyme falling into mixture
  • bonds may chnage shape of enzyme site resulting in lower activity
66
Q

how does covalent bonding work for immobilising enzymes

A

enzymes are bounded to a surface like clay, porous carbon, resins or glass beads by covalent bonds

67
Q

advantages of using covalent bonds

A
  • stronger so less likely for enzymes to break off

- enzymes can attach to each pother via covalent bonds

68
Q

disadvantages of using covalent bonds

A
  • expensive

- -bonds may chnage shape of enzyme site resulting in lower activity

69
Q

how does entrapment work

A

enzymes are trapped in a cellulose matrix that does not allow movement of enzymes but they remain active

70
Q

advantage of entrapment

A

enzymes remain fully active so reaction rate does not change

71
Q

disadvantage of entrapment

A

molecules need to be small

72
Q

how does membrane separation work

A

-are separated form the reaction mixture via a partially permeable membrane

73
Q

advantage of membrane sepeation

A

enzyme remains fully active so no change in reaction rate

74
Q

disadvantage of membrane serperation

A

molecules must be small

75
Q

what does glucose ismoerase do

A
  • coverts glucose to fructose

- used to produce high fructose corn syrup which is very sweet makes low calorie foods

76
Q

what does penicillin acylase do

A

creates synthetic penicillin

77
Q

what does lactase do

A

coverts lactose to glucose and galactose

78
Q

what does amino acylase do

A

produces pure samples of L-amino acids

79
Q

what does glucoamylase do

A

converts dextrins to glucose

80
Q

what does nitrile hydrase do

A

converts nitriles to aimides

A2 Biology OCR (25 decks)

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