Biology (6.4): Cloning and biotechnology

clones

clones

genetically identical organisms

eukaryotic cells

cells with membrane-bound organelles including a nucleus

prokaryotic cells

bacterial cells that lack membrane-bound organelles like a nucleus

genetic variation

differences in DNA and genes inherited by organisms compared with other organisms

meristem tissue

unspecialised tissue in plants

auxin

hormone that promotes cell elongation in shoot cells and inhibits cell elongation in root cells

natural selection

increased survival and reproduction in certain variations of organisms due to inheriting beneficial alleles which over time become more common in the population

Benefits of asexual reproduction (4)

1. all beneficial features passed on to next generation

2. only one individual

3. rapid population increase

4. no energy used to find mates or pollinate

Disadvantages of asexual reproduction (4)

1. population grows excessively

2. minimal diversity nor variation

3. limit natural selection

4. populations vulnerable to environmental change

vegetative propagation

when plants reproduce asexually using unspecialised vegetative tissue and not using specialist reproductive organs

stolons or runners

horizontal stems that can lead to the production of cloned plants

examples of asexual reproduction in animals (2)

1. monozygotic twins (embryo splitting)

2. insects

Examples of artificial cloning in plants (2)

1. cuttings

2. micro-propagation

How do you make a leaf cutting? (5)

1. select healthy shoot from stem

2. cut at angle between two nodes

3. dip cut end in rooting powder

4. plant in soil and water

5. reduced transpiration by covering with a bag

Steps of micro-propagation (3)

1. meristems removed

2. sterilised and placed on agar with auxins

3. sterile plantlets grow and are transplanted to soil

Benefits of artificially cloning plants in agriculture (6)

1. faster

2. seedless plants

3. microprop is aseptic

4. predictable features

5. cuttings more robust than young seedlings

6. not reliant on seasons

Drawbacks of artificially cloning plants in agriculture (3)

1. costly

2. uniformity

3. asepsis hard to accomplish

What are the two different reasons for cloning?

reproductive and non-reproductive cloning

reproductive cloning

grow cloned embryos into adult organisms

non-reproductive cloning

grow cloned embryos only as a supply of stem cells

Why would you need a supply of stem cells (made in non-reproductive cloning) (2)

1. replace damaged tissues with matched stem cells and treat diseases

2. research

What are two different ways of cloning? (2)

1. embryo twinning

2. SCNT

embryo twinning

cells of a developing embryo are split apart to form many genetically identical embryos

SCNT

makes an embryo which is a clone of an existing adult

Stages of artificial embryo twinning (5)

1. embryo produced by IVF from parents with desirable characteristics

2. embryonic cells are split apart

3. cells undergo mitosis and develop identical embryos

4. embryos implanted into surrogates

5. identical offspring from all surrogates

What does SCNT stand for?

Somatic cell nuclear transfer

Stages of SCNT (5)

1. eunucleation

2. nuclear transfer

3. electro-fusion

4. implantation

5. clone born

What happens in eunucleation in SCNT?

nucleus removed from unfertilised egg from donor

What happens in nuclear transfer in SCNT?

nucleus transferred from any body cell to genetic donor

What happens in electro-fusion in SCNT?

electric shock to stimulate fusion and mitosis

What happens in implantation in SCNT?

embryo inserted into uterus of a surrogate

Arguments for cloning (5)

1. fix characteristics of an entire population

2. research for studying specific genotypes

3. tissue-matched drug testing

4. therapeutic cloning

5. conservation of endangered species

Arguments against cloning (4)

1. uniformity/lack of diversity

2. unhealthy

3. embryological ethics

4. could lead to reproductive cloning of humans

biotechnology

the industrial scale use of living organisms to produce food, drugs or other chemicals for human use

what is biotechnology used for? (3)

1. food production

2. drug production

3. biochemical reactions

Uses of biotechnology in food production (4)

1. brewing

2. baking

3. cheese making

4. yoghurt

Uses of biotechnology in drug production (2)

1. penicillin

2. insulin

Use of biotechnology in biochemical reactions

bioremediation

benefits of microbes in biotechnology (6)

1. short life-cycles

2. cold production

3. 1atm

4. climate independent

5. use waste products

6. fewer ethical objections

What organism is used when brewing alcoholic beverages?

yeast

What is the method for brewing alcoholic beverages? (3)

1. sugars from grain/fruit are anaerobically respired by yeast

2. forms CO₂ and ethanol

3. ethanol added to beverages

What organism is used in bread making?

yeast

What is the method for bread making? (3)

1. yeast, water, flour and salt mixed

2. warmed whilst yeast anaerobically respire

3. bread

Organism used in cheese making

lactobacillus

Method for making cheese (5)

1. lactobacillus added to milk

2. produces lactic acid - denatures protein

3. rennet added to coagulate

4. forms curd & separated

5. left to mature

what is rennet from?

mammal stomachs

Organism used in yoghurt making

streptococcus lactobacillus

Method for making yoghurt (2)

1. bacteria added to milk

2. bacteria produce lactic acid from lactose that denatures protein

organism used in making single-cell protein

Fusari

Method of making single-cell protein

fungus is fed waste materials from the paper-making, flour-milling and protein powder making industries

advantages for using microbes for food production (7)

1. fast protein production

2. high protein content

3. on-demand

4. no animals used

5. low fat

6. grown from waste products

7. minimal land use

Disadvantaged for using microbes for food production (6)

1. grown from waste products off-putting

2. inferior taste

3. difficult to isolate

4. purification

5. lacks some amino acids

6. risk of pathogens

fermenter

environmentally-controlled containers that allows industrial scale growth of micro-organisms

types of metabolites

primary and secondary

How are primary metabolites harvested?

continuously

How are secondary metabolites harvested?

in batches

Continuous culture

continuously harvesting primary metabolites from microbes in a fermenter

primary metabolites

substances produced by organisms throughout their life cycles

How is insulin cultured?

continuously

Steps of insulin culturing (5)

1. insulin gene donated and inserted into a vector

2. vector used to transform bacterial cells

3. cells cultured in fermenter

4. insulin protein produced throughout

5. products tapped throughout process

batch culture

harvesting secondary metabolites from microbes in a fermenter in batches

secondary metabolites

substances produced by organisms under stress (e.g. competition as a result of a high popu

How is penicillin cultured?

in batch

Steps of penicillin culturing (5)

1. penicillium fungus cultured in fermenter

2. only when population high, penicillin produced

3. batch ended and filtered

4. penicillin crystals ppt out

5. isolated and prepared as medication

phases of the standard growth curve (4)

1. lag

2. log

3. stationary

4. death

lag phase

acclimatisaton

log phase (2)

1. all resources in excess

2. little competition

Which metabolites are collected in the log phase?

primary meta

Which metabolites are collected in the stationary phase?

secondary metabolites

stationary phase (2)

1. waste product build u

Death phase (3)

1. nutrients depleted

2. waste products toxic

3. organisms die

bioremediation

the use of microorganisms to clean soil or underground water when they use the pollutants (and other additives) as good sources

Benefits of bioremediation

1. biological systems to resolve problem

2. less labour

3. less human exposure to pollutant

4. fewer waste products

Stages of culturing microorganisms (4)

1. aseptic technique

2. culturing

3. incubation

4. dilution

aseptic technique

prevent contamination from other microorganisms

Examples of aseptic techniques (6)

1. hand washing

2. bunsen burner

3. sterile agar

4. sterilise work station

5. flaming equipment and bottlenecks

6. minimal opening of petri dish

What does the presence of a Bunsen burner do during aseptic working?

moves air and any microorganisms in it away from the bench and sterilises the air by killing bacteria

Ways to culture

seeding, spreading and streaking

What is the maximum temperature used for incubation?

25

immobilised enzymes

enzymes that are attached to or enclosed within a supporting structure to increase thermal stability and reusability

What are the types of immobilisation? (4)

1. adsorption

2. covalent bonding

3. entrapment

4. membrane separation

Adsorption (immobilised enzymes)

hydrophobic interactions or ionic links bind enzyme directly to a surface

Covalent bonding (immobilised enzymes)

uses cross-linking agent to bond enzyme to surface

entrapment (immobilised enzymes)

enzymes enclosed within a gel that is permeable to the substrate

membrane separation (immobilised enzymes)

enzyme and substrate separated by a substrate-permeable membrane

advantages of immobilising enzymes (4)

1. no enzyme left in the end product

2. enzyme can be reused

3. more stable and less likely to denature

4. end-product inhibition avoided

disadvantages of immobilising enzymes (2)

1. reaction rate reduced

2. some methods can’t be used if the substrate is insoluble or large

Examples of immobilised enzymes (5)

1. glucose isomerase

2. penicillin acylase

3. lactase

4. amino-acylase

5. gluco-amylase

What is glucose isomerase used for?

conversion of glucose to fructose

What is penicillin acylase used for?

formation of semi-synthetic penicillin (which penicillin resistant organisms aren’t resistant)

What is lactase used for?

hydrolysis of lactose to glucose and galactose

What is amino-acylase used for?

production of pure samples of L-amino acids for making drugs

What is gluco-amylase used for?

conversion of dextrins to glucose (e.g. conversion to bio-ethanol)