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Biology A-Level OCR > Cloning and Biotechnology (Module 6) > Flashcards

Cloning and Biotechnology (Module 6) Flashcards

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1
Q

How do plants naturally clone themselves?

A

Sexual reproduction (mitosis)- plant can form new stem, leaf, bud or root from parent plant using perennating organs

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2
Q

What are perennating organs?

A

An organ that holds nutrients to sustain the organism in unfavourable conditions

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3
Q

Where does natural plant cloning occurs?

A

Bulbs, rhizomes, tubers and runners

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4
Q

Describe how bulbs undergo natural plant cloning?

A

Leaf bases swell stored nutrients and organic solutes from photosynthesis. Buds that develop internally form new shoots and new plants in the new growing season, for instance daffodils

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5
Q

Describe how rhizomes undergo natural plant cloning?

A

Rhizomes are specialised stems that run underground and are often swollen with organic solutes from photosynthesis. This causes buds to form and new vertical shoots grow, which separates into an independent plant. For example, marram grass

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6
Q

Describe how tubers undergo natural plant cloning?

A

Tip of an underground stem becomes swollen with organic solutes from photosynthesis to form a tuber/storage organ. Buds on the storage organ develop and produce new shoots. For example, potatoes

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7
Q

Describe how runners undergo natural plant cloning?

A

Lateral stems grow away from the parent plant and roots develop where the runners touch the ground, a new plant develops and the runner eventually withers away. Such as strawberries and spider plants

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8
Q

What are the advantages of natural plant cloning?

A

Produce plants more cheaply, produce plants quicker than with seeds, produce plants that are genetically identical to the parent plants with desirable traits for agriculture

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9
Q

What are the disadvantages to natural plant cloning?

A

Lack of genetic variation could make the plant susceptible to disease

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10
Q

Name some processes for natural plant cloning

A

Taking cuttings of a non-flowering stem, taking cuttings with an oblique cut into the stem, using hormone rooting powder, reducing leaves to 2 or 4, keeping cutting well watered, covering with plastic for first few days

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11
Q

How can plants be artificially cloned?

A

Micropropagation

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12
Q

When can micropropagation be used?

A

When a desirable plant has no seeds, doesn’t respond well to natural cloning, is very rare, has been genetically modified with difficulty (requires being pathogen free)

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13
Q

Process of micropropagation:

A

1 - create an explant from a tissue sample
2 - sterilise explant
3 - place the explant in a sterile culture with plant hormones to form a callus tissue
4 - Callus tissue is divided into smaller samples and placed onto different culture mediums with different plant hormones to stimulate cell differentiation
5 - plantlets are hardened off and added to compost
6 - the new plants are planted out to produce the new crop of plants

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14
Q

What are the advantages of micropropagation?

A
  • Rapid production of larger numbers of plants with known desirable traits for agriculture, medicine, etc
  • Culturing meristem tissue produces disease-free plants
  • Possible to produce a viable number of plants after genetic modification
  • Possible to produce seedless plants, such as bananas
  • Possible to produce plants that are infertile/difficult to grow from seed
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15
Q

What are the disadvantages of micropropagation?

A
  • Produces a monoculture, so becomes susceptible to disease
  • Expensive process that requires skilled workers
  • Explants and plantlets are vulnerable to disease during production
  • If source material is infected with a virus, all clones will be infected
  • Sometimes, large numbers of plants are lost during production
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16
Q

What is the difference between natural animal cloning in vertebrate and invertebrate animals?

A

Invertebrate animals are very simple, so commonly clone themselves. Vertebrate animals are more complex, so only naturally clone in the form of twinning

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17
Q

How do vertebrates naturally clone?

A

Embryo splitting (to form monozygotic twins)

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18
Q

How do you artificially clone invertebrate animals (sponge and starfish)?

A

Liquidise a sponge and chop up a starfish

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19
Q

Artificial twinning in vertebrate animals:

A

SCNT (somatic cell nuclear transfer) and artificial twinning

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20
Q

Somatic cell nuclear transfer process:

A
  • Nucleus removed from the somatic cell of an adult animal
  • Mature ovum is harvested from a female animal of the same species and is enucleated (nucleus is removed)
  • Somatic cell nucleus is placed within the enucleated ovum and given a mild electric shock to fuse and begin dividing
  • The embryo is placed within the uterus of a third animal of the same species to gestate
  • The cloned animal is a clone of the animal that had the somatic cell nucleus removed, but the mitochondrial DNA will come from the egg cell of the female animal
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21
Q

Artificial twinning:

A
  • Cow with desirable traits is given hormones to super-ovulate, so releases more eggs than usual
  • Eggs may be fertilised naturally or via artificial insemination by a bull with desirable traits (or fertilised in the lab)
  • Early embryos flushed out of the uterus
  • Whilst the embryo is still totipotent, it is split into several sections that are each capable of growing an individual calf
  • Each embryo is grown in the lab for a few days and then inserted into individual cows to reduce risk of pregnancy complications
  • The embryos will form calves that are all identical to each other- but not genetically related to the mothers that carried them
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22
Q

Arguments for animal cloning:

A
  • Increases yield of livestock

- Quicker reproduction of rare or endangered animals

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23
Q

Arguments against animal cloning:

A
  • SCNT is very inefficient, requiring 3 animals to produce one offspring
  • Many mothers may miscarry or produce malformed offspring
  • Offspring may have shorter lifespan
  • Offspring may have associated health risks
24
Q

Why are microorganisms used in biotechnology?

A
  • No welfare issues
  • Short life cycle
  • Nutrient requirements cheap
  • Microorganisms make their own specific catalysts for reactions (enzymes)
  • Genetic engineering available as they have a small genome
25
Q

Uses of microorganisms:

A

Brewing, baking, cheese-making, penicillin production, insulin production, etc

26
Q

Biotechnology definition:

A

Application of organisms or enzymes for the service of people

27
Q

Disadvantages for use of microorganisms in biotechnology:

A
  • If growing conditions are not ideal, the microorganisms do not grow properly- which effects the production of the product/enzymes
  • Conditions that are ideal for the desired organism may also be ideal for undesirable organisms that make the food go off
28
Q

Indirect vs direct food production:

A

Indirect: microorganisms catalyse reactions that produce the desired food (cheese, bread and alcohol)
Direct: microorganisms directly make the desired foods (Quorn)

29
Q

Bioremediation:

A

Microorganisms are used to break down pollutants in water and soil

30
Q

Risks associated with culturing ‘harmless’ bacteria:

A
  • Mutation may occur to make them more harmful

- May have been contaminated by a pathogen

31
Q

Inoculating a broth:

A
  • Add bacterial suspension to sterile nutrient broth in flask
  • Add wool stopper to flask to prevent contamination
  • Incubate at suitable temperature and shake at periods to aerate (provide oxygen to microorganisms)
32
Q

Inoculating an agar plate:

A
  • Sterilise wire loop in Bunsen burner
  • Dip loop in bacterial suspension and draw zig-zag lines across the plate
  • Tape closed plate, but not completely so oxygen is still present (prevent growth of anaerobic bacteria)
  • Incubate at suitable temperature
33
Q

Four stages of the bacteria growth curve:

A

Lag phase, exponential phase, stationary phase, death phase

34
Q

Lag phase:

A

Bacteria are adapting to an environment, birth = death

35
Q

Exponential phase:

A

Birth > death (at it’s theoretical maximum)

36
Q

Stationary phase:

A

Birth = death, new cells formed by binary fission are cancelled out by cell death

37
Q

Death phase:

A

Birth < death, reproduction rate decreases

38
Q

Limiting factors on the exponential phase:

A
  • Build up of waste products: build-up of toxic products due to population growth may inhibit further growth
  • pH: as population increases, the concentration of CO2 also increases from the increase in respiration- a continued increase in CO2 conc. decreases pH to the point where essential enzymes cannot function
  • Nutrients available: as the population increases, so does the demand for nutrients
  • Oxygen levels: as the population increases, so does the demand for respiratory oxygen
39
Q

Primary metabolite:

A

Formed in period of active growth (formed as an essential part to normal function) such as ethanoic acid, amino acids and enzymes

40
Q

Secondary metabolite:

A

Formed in stationary phase (period where no active growth is occurring, not essential to normal function) such as penicillin

41
Q

Batch fermentation:

A
  • Microorganisms inoculated in fixed volume of sterile solution
  • Growth takes place, causing nutrients to be used and waste products to build up
  • As the culture reaches the stationary phase, overall growth ceases but microorganisms will often undergo a biochemical change into an enzyme or an antibiotic (desired end products)
  • Products are harvested before the death phase and the machinery is sterilised, and then the process repeats
42
Q

Continuous fermentation:

A
  • Microorganisms are inoculated into a sterile growth medium
  • Sterile nutrient medium is continuously added once reaching the exponential phase
  • Culture broth is also removed, containing waste products, microorganism, nutrient medium and the desired product- in order to maintain the culture volume
43
Q

Importance of controlling conditions in fermentation:

A

Maximise yield of desired product

44
Q

Controlled conditions in fermentation:

A
  • Temperature: too high will denature the enzymes within the microorganism (causing inhibition of growth or death), too low will lower the rate of reproduction
  • Nutrients and oxygen
  • Mixing the solution: ensures that the microorganisms have access to all the nutrients they require
  • Sealed units: prevent external contamination
45
Q

Advantages of isolated enzymes:

A
  • Less wasteful
  • More efficient
  • More specific
  • No downstream processing (only desired product is produced, no unwanted waste products)
46
Q

Advantages of isolated enzymes being extracellular:

A
  • Are excreted, so easy to isolate
  • Microorganisms have relatively few extracellular enzymes, so easy to identify
  • More robust due to less controlled conditions outside of cells/cytoplasm
47
Q

Why are intercellular enzymes still used as isolate enzymes despite being harder to extract?

A

Larger range of enzymes for specific processes

48
Q

Examples of intercellular isolated enzymes:

A
  • Glucose oxidase (food preservation)

- Penicillin acylase (converts naturally occurring penicillin into semi-synthetic drugs)

49
Q

Immobilised enzyme:

A

Isolated enzymes that have been attached to an inert support that has substrate run over it to produce the desired product

50
Q

Advantages of immobilised enzymes:

A
  • Can be reused, which is cheaper
  • Easily separated from reactants and products
  • More reliable
  • Greater temperature tolerance
  • Ease of manipulation
51
Q

Disadvantages of immobilised enzymes:

A
  • Reduced efficiency (process of immobilising enzyme may damage efficiency)
  • Higher initial costs
  • More technical issues due to increased complexity of machinery
52
Q

Methods of immobilising enzymes:

A

Surface immobilisation (by adsorption or ionic/covalent bonding to inorganic carrier) or entrapment in matrix or encapsulation

53
Q

Surface immobilisation - adsorption:

A
  • adsorption to cellulose, silica etc
  • Advantages: simple and cheap, can be used in many different processes, enzymes accessible to substrate and activity is unchanged
  • Disadvantages: enzymes can be lost from matrix easily
54
Q

Surface immobilisation - ionic/covalent:

A
  • Covalent bonding to amino, hydroxyl or carboxyl groups
  • Ionic bonding to polysaccharides (cellulose)
  • Advantages: enzymes strongly bound and so unlikely to be lost, enzymes accessible to substrate, pH/substrate conc. do not have large effect of enzyme activity
  • Disadvantages: cost varies, active site of enzyme may be modified during immobilisation- so may become less effective
55
Q

Entrapment - matrix

A
  • Polysaccharide or gelatine entrapment
  • Advantages: widely adaptable to many different processes
  • Disadvantages: expensive, can be difficult to entrap, diffusion to/from the active site can slow down the process, matrix may effect enzyme activity
56
Q

Entrapment - membrane entrapment in microcapsules

A
  • Entrapped in polymer-based semi-permeable membrane
  • Advantages: simple to do, small effect on enzyme activity, widely applicable to several processes
  • Disadvantages: expensive, diffusion to/from the active site can slow down the process
57
Q

Examples of immobilised enzymes:

A
  • Immobilised lactase (used to make lactose-free milk)
  • Immobilised glucose isomerase (used to produce glucose –> fructose to be used as a sweetener)
  • Immobilised penicillin acylase (converts naturally occurring penicillin into semi-synthetic drugs)
  • Immobilised aminoacylase (produces pure L-amino acids for pharmaceuticals, cosmetics and food)

Biology A-Level OCR (26 decks)

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