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A level Biology xoyzq > Biotechnology 6.2.1 > Flashcards

Biotechnology 6.2.1 Flashcards

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1
Q

why are microorganisms used in biotechnology?

A
  • cheap
  • short life cycle
  • rapid growth rate
  • simple nutrient requirement
  • relatively low temp

also. .
- no welfare issues
- enormous range of microorganisms which can carry out many functions
- GM allows manipulation of microorganisms to carry out unnatural reactions eg. producing human insulin
- raw materials cheap

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2
Q

bioremediation

A

use of biological systems (usually microorganisms) to remove soil and water pollution eg. after oil spill

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3
Q

Brewing
microorganism used
process described

A

Yeast
- respires aerobically, making ethanol

  • yeast is added to a grain eg. barley
  • batch culture
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4
Q

Cheese making
microorganism used
process described

A

Bacteria
- feed on lactose in milk (change texture & taste, and inbihits the growth of bacteria which make milk go off)

  • pasteurise milk (heat to 95C) and homogenise (fat droplets are evenly distributed)
  • mix w bacterial cultures, and chymosin enzyme, which clots the milk
  • milk separates into solid curds and liquid whey
  • cook & strain
  • put in drums and left to mature & ripen as bacteria continue to act
  • batch culture
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5
Q

Yoghurt production
microorganism used
process described

A

Bacteria

  • Lactobacillus bulgaricus (forms ethanal)
  • Streptococcus thermophilus (forms lactic acid)
  • mixture is pasteurised, homogenised, & cooled
  • milk mixed w two types of bacteria & incubated
  • flavours can be added
  • batch culture
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6
Q

Penicillin production
what makes penicillin?
how is it grown commercially?

A
  • Fungus (Penicillium chrysogenum) produces the antibiotic penicillin which stops bacteria from growing
  • grown under stress in industrial fermenters (batch), collected and processed
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7
Q

Insulin production

A

GM bacteria have the gene for human insulin production inserted into their DNA

  • grown in an industrial fermenter (continuous culture)
  • insulin is collected and purified
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8
Q

advantages of using microorganisms to make food for human consumption

A

+ grow fast
+ short life cycle
+ cheap
+ simple growth requirements
+can be grown on waste products
+ less land is req. than w/ agriculture
+ can be cultured in any climate or season
+ any country (can be used in LEDCs for malnutrition)
+ single-cell protein can be healthy alternative to meat
+ no welfare issues

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9
Q

disadvantages of using microorganisms to make food for human consumption

A
  • must maintain aseptic conditions so that other microorganisms do not grow & contaminate food
  • people may not like the idea of eating food grown from waste products
  • single-cell protein doesn’t have the same flavour or texture as meat
  • the fungus used to make Quorn is hight in nucleic acids, which are metabolised to uric acid in the body. This can cause gout.
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10
Q

how to culture microorganisms in the lab

A
  • use sterile petri dish with agar jelly
  • transfer microorganisms from sample to the plate using a sterile wire inoculation loop
  • incubate the plates to allow the microorganisms to grow
  • nutrients added to the agar to improve growing conditions
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11
Q

what type of fermentation is used when growing Quorn from a fungus?

A

continuous fermentation

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12
Q

Batch fermentation

A

Batch fermentation

  • closed culture.
  • microorganisms grown in discrete batches in an industrial fermenter.
\+ produces secondary metabolites
\+ easy to control conditions
\+ contamination only affects one batch
- large vessels needed
- waste builds up
- less productive as exponential phase is short
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13
Q

Continuous fermentation

A

Continuous fermentation

  • open culture.
  • microorganisms are grown continuously
  • nutrients are put in and waste products are taken out at a constant rate

+ greater productivity as organisms are kept in the exponential phase
+ no need to empty and sterilise the fermenter
- difficult to control conditions
- no secondary metabolites produced
- large quantity can be spoiled if contaminated

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14
Q

Continuous fermentation

A

Continuous fermentation

  • open culture.
  • microorganisms are grown continuously
  • nutrients are put in and waste products are taken out at a constant rate

+ greater productivity as organisms are kept in the exponential phase
+ no need to empty and sterilise the fermenter
- difficult to control conditions
- no secondary metabolites produced
- large quantity can be spoiled if contaminated

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15
Q

aseptic techniques when culturing microorganisms

A
  • work near bunsen as hot air carries microorganisms in the air up
  • disinfect work surfaces
  • sterilise instruments (wire inoculation loop) by passing through flame to kill microorganisms
  • pass neck of bottle through flame after opening and before closing to prevent microorganisms falling in
  • minimise time agar plate is open and seal lid as fast as possible
  • sterilise glassware in autoclave machine (steam at high pressure)
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16
Q

describe the stages of a standard growth curve for the growth of microorganisms in a closed culture

A

Lag phase

  • pop size slowly increases
  • microorganisms have to absorb nutrients, make enzymes etc before they can reproduce

Exponential phase

  • pop size increases quickly as the culture conditions are the most favourable for reproduction (lots of food and little competition)
  • reproduction rate is v fast (exponential)

Stationary phase

  • pop stays level as the death rate = reproductive rate
  • microorganisms start to die as not enough food and toxic waste builds up

Decline phase

  • pop falls as death rate > reproduction rate
  • food v scarce
  • lots of toxic waste products
17
Q

what 5 factors need to be regulated in a fermentation vessel to maximise yield of microorganisms?

A
  • pH
  • temp
  • nutrient access
  • vol of O2
  • sterility
18
Q

how is pH regulated in a fermentation vessel?

A

pH probe

19
Q

how is temperature regulated in a fermentation vessel?

A

water jacket

20
Q

how is nutrient access regulated in a fermentation vessel?

A

paddles constantly circulate fresh nutrient medium around the vessel

21
Q

how is vol of O2 regulated in a fermentation vessel?

A

sterile air pumped into vessel as needed for aerobic resp

22
Q

how is sterility regulated in a fermentation vessel?

A

the vessel is superheated with steam after each use to kill all microorganisms

23
Q

what formula is used to calculate the no. individual organisms at any given time in a fermentor (batch)

A

N = N₀ x 2ⁿ

where
N - no. individuals
N₀ - no. initial individuals
n - no. generations

24
Q

how to conduct an investigation into the factors affecting the growth of microorganisms in the lab

A

eg. temp

  • add same vol of sample to several agar plates
  • spread broth across surface of agar using sterile wire inoculation loop
  • put lids on the plates and tape shut
  • incubate at diff temps upside down to prevent condensation dropping onto the agar
  • use a control (uncultured plate)
  • leave for same amount of time (24h)
  • count no. colonies on each plate
25
Q

what are the 3 ways enzymes can be immobilised?

A
  • encapsulated in jelly-like beads which act as a semi-permeable membrane
  • trapped in silica gel matrix
  • covalently bonded to cellulose/collagen fibres
26
Q

advantages of using immobilised enzymes

A

+ columns can be washed and reused, reducing cost
+ product doesn’t need to be separated from enzymes, reducing time and cost
+ immobilised enzymes are more stable than free enzymes - less likely to denature at high temps or pH

27
Q

disadvantages of using immobilised enzymes

A
  • extra equipment required which is expensive to buy
  • immobilised enzymes are more expensive to buy outright
  • enzyme activity may be reduced as the enzyme can’t freely mix with its substrate
28
Q

what does glucose isomerase do

A

converts glucose → fructose

which can be used as a sweetener as it is sweeter than glucose

29
Q

what does penicillin acylase do

A

forms semi- synthetic penicillins, which are effective on penicillin resistant organisms

30
Q

what does lactase do

A

hydrolysis of lactose
lactose → glucose + galactose

to produce lactose-free milk for lactose intolerant people

31
Q

what does aminoacylase do

A

production of pure samples of L-amino acids

amino acids have 2 isomers (L&D) but only L a.as are made naturally and can be used in the body. Aminoacylase can be used to convert chemically synthesised a.as to L a.as

32
Q

what does glucoamylase do

A

converts dextrins from starch into glucose

glucose is then used to sweeten/thicken foods

33
Q

biotechnology

A

industrial use of living organisms (or parts of living organisms) to produce food, drugs or other product.

A level Biology xoyzq (33 decks)

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