Module 6 Section 5 - Cloning and Biotechnology

Question 1

Cloning definition?

Answer 1

Cloning is the process of producing genetically identical cells or organisms from the cells of an existing organism

Question 2

What is vegetative propagation?

Answer 2

The production of plants clones from non-reproductive tissues, eg roots, leaves and stems. It’s a type of asexual reproduction.

Question 3

What are some examples of natural vegetative propagation?

Answer 3

1) rhizomes- these are stem structures that grow horizontally underground from the parent plant. They have “nodes” from which new shoots and roots can develop. An example of a plant that uses rhizomes is bamboo.

2) Bulbs- these are also underground food stores used by some plants. New bulbs are able to develop from the original bulb, and form new individual plants. An example of a plant that uses bulbs is the onion.

3) Runners- usually in strawberry or spider plants. Lateral stems grow away from the parent plant and roots develop where the runner touches the ground. A new plant develops, and the runner withered away leaving the new plant independant.

Question 4

What are some methods of vegetative propagation?

Answer 4

1) they can take cuttings

2) they can use grafting- joining the shoot of one plant to the growing stem and root of another plant.

3) they can use layering - bending a stem of a growing plant downwards so it enters the soil and grows into a new plant

Question 5

How to produce a clone from cuttings?

Answer 5

1) use a scalpel to take a cutting between 5-10cm long, from the end of a stem of your parent plant. Make sure plant is healthy. Cut at a slant between nodes

2) remove the leaves from the lower end of the cutting, leaving one at the tip.

3) dip the lower end of the cutting in rooting powder, which contains hormones that induce root formation.

4) then plant your cutting in a pot containing a suitable growth medium (eg well drained compost).

5) provide your cutting with a warm and moist environment, by covering the whole pot with a plastic bag or by putting it in a propagator.

6) when the cutting that formed it’s own roots and is strong enough, you can plant it elsewhere to continue growing.

Question 6

How is tissue culture carried out?

Answer 6

1) cells are taken from the original plant that need to be cloned. Cells from the stem and root tips are used because they’re stem cells, like in humans, plant stem cells can develop into any type of cell. The cells removed are called the ex plant.

2) the cells are sterilised with ethanol to kills any microorganisms, bacteria and fungi compete for nutrients with the plant cells, which decrease growth rate.

3) the cells are placed on a culture medium containing organic nutrients and a high concentration of plants hormones. This is carried out under aseptic conditions. The cells divide to produce a mass of undifferentiated cells.

4) when the cells have divided, the mass of cells is called the callus.and grown into a small plant they’re taken out of the medium and planted in soil, they’ll develop into plants that are genetically identical to the original plant.

Question 7

What are the use of tissue culture?

Answer 7

1) tissue culture is used to clone plants that don’t readily reproduce or are rare or endangered.

2) it’s also used to grow whole plants from genetically engineered plant cells.

Question 8

What is micropropagation?

Answer 8

Micropropagation is when tissue culture is used to produce lots of cloned plants very quickly. Cells are taken from developing cloned plants and subcultured (grown on another fresh culture medium) - repeating this process creates large numbers of clones.

Question 9

What are the arguments for artificial plant cloning?

Answer 9

1) desirable genetic characteristics (eg high fruit production) are always passed on to clones. This doesn’t always happen when plants reproduce sexually.

2) tissue culture allows plants to be reproduced in any season because the environment is controlled.

3) less space is required by tissue culture than would be needed to produce the same number of plants by conventional growing methods.

4) it produces lots of plants quickly compared to the time it would take to grow them from seeds.

Question 10

Arguments against artificial plant cloning?

Answer 10

1) undesirable genetic characteristics are always passed on to clones.

2) cloned plant populations have no genetic variability, so a single disease could kill them all.

3) production costs of tissue culture are very high due to high energy use and the training of skilled workers, so it’s unsuitable for small scale production.

4) contamination by microorganisms during tissue culture can be disastrous and result in complete loss of the plants being cultured.

Question 11

What are natural animal clones?

Answer 11

Animal clones can be produced naturally as a result of sexual reproduction. During sexual reproduction, once an egg has been fertilised, it’s possible for it to split during the very early stages of development and develop into multiple embryos with the same genetic information. The embryos can develop as normal to produce offspring that are all genetically identical. Identical Twins are natural clones.

Question 12

What are the two methods of artificial cloning in animals?

Answer 12

1) artificial embryo twinning

2) somatic cell nuclear transfer.

Question 13

How does artificial embryo twinning?

Answer 13

1) an egg cell is extracted from a female cow and fertilised in a Petri dish.

2) the fertilised egg is left to divide at least once, forming an embryo in vitro.

3) next, the individual cells from the embryo are seperated and each is put into a seperate Petri dish. Each cell divides and develops normally, so an embryo form in each Petri dish.

4) the embryos are then implanted into female cows, which act as surrogate mothers.

5) the embryos continue to develop inside the surrogate cows, and eventually the offspring are born. They’re all genetically identical to each other.

Question 14

How does somatic cell nuclear transfer work?

Answer 14

1) a somatic cell is taken from sheep A. The nucleus is extracted and kept.

2) an oocyte is taken from sheep B. It’s nucleus is removed to form an enucleated oocyte.

3) the nucleus forms sheep A id inserted into the enucleated oocyte. The oocyte from sheep B now contains the genetic information from Sheep A.

4) the nucleus and the enucleated oocyte are fused together by electrofusion and stimulated to divide. This produces an embryo.

5) then the embryo is implanted into a surrogate mother and eventually a lamb is brown that is a clone of sheep A.

Question 15

What are the uses of animal cloning?

Answer 15

1) research purposes- they can test new drugs on cloned animals. They are genetically identical so genetic differences are removed.

2) cloning can be used in agriculture so farmers can increase the number of animals with desirable characteristics to breed from.

3) animals that have been genetically modified to produce a useful substance that they wouldn’t normally produce could be cloned to produce lots of identical animals with the same substance.

4) cloning could also be used to save endangered animals from extinctions by cloning new individuals.

5) sometimes scientists only want cloned embryonic stem cells. These cells are harvested from young embryos which can be used to replace damaged tissues in a range of diseases, eg heart disease and Parkinson’s disease.

Question 16

Arguments for animal cloning?

Answer 16

1) desirable genetic characteristics are always passed on to clones. This doesn’t always happen with sexual reproduction.

2) infertile animals can be reproduced.

3) animals can be cloned at any time. You do not have to wait until breeding season to get new animals.

4) increasing the population of endangered species helps to preserve biodiversity.

5) cloning can help us develop new treatments for disease, which could mean less suffering for some people.

Question 17

Arguments against animal cloning?

Answer 17

1) animal cloning is very difficult, time consuming and expensive.

2) there is no genetic variability in cloned populations, so undesirable characteristics are always passed on to clones. This means all the cloned animals in a population are susceptible to the same disease, so potentially one disease could wipe them all out.

3) some evidence suggests that clones may not live as long as natural offspring. Some think this is unethical.

4) using cloned human embryos as a source of stem cells is controversial. The embryos are usually destroyed after the embryonic stem cells have been harvested- some people believe that doing this is destroying a human life.

Question 18

What is biotechnology?

Answer 18

Biotechnology is the industrial use of living organisms to produce food, drugs, and other products.

Question 19

Why are microorganisms used in biotechnology?

Answer 19

1) their ideal growth conditions can be easily created. Microorganisms will generally grow successfully as long as they have the right nutrients, temperature, pH, moisture levels and availability of gases.

2) due to their short life cycle, they grow rapidly under the right conditions, so products can be made quickly.

3) they can grow on a range of inexpensive materials, this makes them economical to use.

4) they can be grown any time of year.

Question 20

How are microorganisms used in brewing?

Answer 20

To make beer, yeast is added to a type of grain eg barley and other ingredients. The yeast respires anaerobically using the glucose from the grain and produces ethanol, and CO2. When anaerobic respiration produces ethanol, the process is called fermentation.

Question 21

How are microorganisms used in baking?

Answer 21

Yeast makes bread rise. The CO2 produced by fermentation of sugars in the dough makes sure it doesn’t stay flat.

Question 22

How are microorganisms used in cheese making?

Answer 22

Cheese production relies on rennet. Rennet contains the enzyme chymosin, which clots milk. Chymosin is obtained from yeast cells that have been genetically modified to produce the enzyme. Cheese making also involves lactic acid bacteria. These bacteria convert the lactose in milk into lactic acid, which makes it sour, and contributes to making it solid. The production of blue cheese also involves the addition of fungi to make blue veins.

Question 23

How are microorganisms used in yogurt production?

Answer 23

Yogurt production uses lactic acid bacteria to clot the milk, and cause it to thicken. This creates a basic yogurt, and then any flavours and colours are added.

Question 24

How are microorganisms used to produce penicillin?

Answer 24

In times of stress, fungi from penicillium genus produce an antibiotic penicillin, to stop bacteria from growing and competing for resources. Penicillin is one of the most common antibiotics used in medicine so it produced on mass scale. The fungus is grown under stress in industrial fermenters and the penicillin produced is collected and processed to be used in medicine.

Question 25

How are microorganisms used for insulin production?

Answer 25

Insulin is a hormone used to treat type 1 diabetes. Insulin is usually made from genetically modified bacteria, which have had the gene for human insulin inserted into their DNA. These bacteria are grown in an industrial fermenter on a massive scale and insulin is collected and purified.

Question 26

How are microorganisms used for bioremediation?

Answer 26

This is the process of using organisms ti remove pollutants like oil and pesticides, from contaminated sites. Most commonly, pollutant-removing bacteria that occur naturally at a site are provided with extra nutrients and enhanced growing conditions to allow to multiply and thrive. These bacteria break down the pollutants into less harmful products, cleaning up the area.

Question 27

Advantages of using microorganisms in food production?

Answer 27

1) microorganisms used to make single cell protein can be grown using many different organic substrates, including waste materials such as molasses. Production of single cell protein could actually be a way of getting rid of waste products. 2) microorganisms can be grown quickly, easily and cheaply. Production costs are low because microorganisms have simple growth requirements, can be grown on waste products and less land is required in comparison to growing crops or rearing livestock. 3) microorganisms can be cultured anywhere if you have the right equipment. This means that a food source could be readily produced in places where growing crops and rearing livestock is difficult (eg hot and cold climates). This could help tackle malnutrition in developing countries. 4) single cell protein is also often considered a healthier alternative to animal protein.

Question 28

Disadvantages of using microorganisms in food production?

Answer 28

1) the conditions needed to grow the desired microorganism are also ideal for other microorganisms, a lot effort has to go into making sure food does not get contaminated with unwanted bacteria, which could be dangerous to humans or spoil the food. 2) people may not like the idea of eating food that has been grown using waste products. 3) single cell protein doesn’t have the same texture or flavour as real meat. 4) if single cell protein is consumed in high quantities, health problems could be caused due to high levels of uric acid released when the large amounts of amino acid are broken down.

Question 29

What is a culture?

Answer 29

A culture is a population of one type of microorganism that’s grown under controlled conditions.

Question 30

What are the two main methods for culturing microorganisms?

Answer 30

1) batch fermentation 2) continuous fermentation

Question 31

What is batch fermentation?

Answer 31

This is where microorganisms are grown in individual batches in a fermentation vessel. When on e culture ends, it’s removed and then a different batch of microorganisms are grown in the vessel

Question 32

What is continuous fermentation?

Answer 32

This is where microorganisms are continually grown in a fermentation without stopping. Nutrients are put in and waste products are taken out at a constant rate.

Question 33

What factors need to be controlled in a fermentation vessel?

Answer 33

1) pH- monitored by pH probe and kept at an optimum level. This ensures enzymes are working properly. 2) temperature- kept at optimum using water jacket that surrounds vessel. Keeps enzymes working efficiently. 3) oxygen supply- sterile air is pumped into vessel for respiration.. 4) nutrient concentration - paddles circulate the medium around the vessel. 5) contamination- vessels are sterilised between uses with superheated steam

Question 34

What is a closed culture?

Answer 34

A closed culture is when growth takes place in a vessel that’s isolated from the external environment. Extra nutrients aren’t added and waste products aren’t removed from the vessel during growth.

Question 35

What are the four phases in a standard growth curve?

Answer 35

1) lag Phase 2) exponential (log) phase 3) stationary phase 4) decline phase

Question 36

What happens in the lag phase?

Answer 36

The population size increases very slowly because the microorganisms have to make enzymes and other molecules before they can reproduce. This means the reproduction rate is low.

Question 37

What happens in the exponential phase?

Answer 37

The population size increases quickly because the culture conditions are at their most favourable for reproduction. The number of microorganisms doubles at regular intervals

Question 38

What happens in the stationary phase?

Answer 38

The population size stays level because the death rate of the microorganisms equals their reproduction rate. Microorganisms die because there’s not enough food and poisonous waste products build up.

Question 39

What happens in the decline phase?

Answer 39

The population size falls because the death rate is greater than the reproductive rate. This is because food is scarce ans waste products are at toxic levels.

Question 40

How to culture microorganisms in a lab?

Answer 40

Use a sterile implement like a wire inoculation loop to transfer the sample, which could then be gently spread across the surface of the agar using a glass or plastic spreader. The plates then need to be incubated to allow the microorganisms to grow.

Question 41

What are aseptic techniques?

Answer 41

These are used to prevent contamination of cultures by unwanted microorganisms, which may affect the growth of the microorganims being cultured. Examples include 1) regularly disinfecting work surfaces 2) work near Bunsen flame 3) sterilise equipment used to transfer cultures 4) minimise time agar plate is open 5)sterilise all glassware using autoclave 6) wear a labcoat and gloves if needed

Question 42

Method to investigate factors that affect growth of microorganisms?

Answer 42

1) use sterile Pipette to add the same volume of sample to 6 agar plates. Discard or clean Pipette after use 2) spread broth across entire surface of agar using sterile plastic spreader. Discard spreader after use 3) Put lids on agar plates and tape them shut. 4) place 3 plates in fridge and 3 plates in incubator at 25 degrees Celsius. The plates should be incubated upside down to prevent condensation forming on the lid dropping onto the agar. 5) put another lidded uncultured agar plate into each temperature. These act as negative controls 6) leave all plates for same amount of time eg 24 hours. If bacterial growth has occurred, you should see colonies of bacteria on the surface of the agar.

Question 43

What are immobilised enzymes?

Answer 43

Enzymes that are attached to an insoluble material so they cannot be mixed with the products.

Question 44

What are the four ways enzymes are immobilised?

Answer 44

1) encapsulated in jelly like alginate beads, which act as a semi permeable barrier 2) adsorption- bind to immobilising support by hydrophobic interactions and ionic links 3) covalently bonded to cellulose or collagen fibres 4) membrane seperation- seperated by partially permeable membrane.

Question 45

Advantages of using immobilised enzymes?

Answer 45

1) columns of immobilised enzymes can be washed and reused. This reduces the cost of running the reaction on an industrial scale because you don’t have to keep buying new enzymes 2) the product isn’t mixed with the enzymes. No money or time is spent separating them out. 3) immobilised enzymes are more stable than free enzymes . They’re less likely to denature in high temperatures or extremes of pH

Question 46

Disadvantages of using immobilised enzymes?

Answer 46

1) extra equipment is required, which can be expensive to buy 2) immobilised enzymes are more expensive to buy than free enzymes, so coupled with the equipment costs, they’re not always economical for use in smaller scale productions 3) the immobilisation of the enzymes can sometimes lead to a reduction in the enzyme activity because they can’t freely mix with their substrate.

Question 47

How are immobilised enzymes used to convert lactose to glucose and galactose?

Answer 47

Industrially, fresh milk can now be passed over immobilised lactase to produce lactose free milk for use in the production of lactose free dairy products

Question 48

How are immobilised enzymes use in the Production of semi synthetic penicillins?

Answer 48

Semi synthetic penicillins can be produced that have the same antibiotic properties at natural penicillin but are effective against penicillin resistant organisms. Immobilised penicillin acylase enzyme is used in their production

Question 49

Use of immobilised enzymes in conversion of dextrins to glucose?

Answer 49

Starch breaks down dextrins which are then broken down into glucose by the immobilised enzyme glucoamylase.

Question 50

Use of immobilised enzymes in conversion of glucose to fructose?

Answer 50

It is used as a sweetener in food. This means that less sugar can be used to obtain the same level of sweetness. Immobilised glucose isomerase is used to convert glucose to fructose on an industrial scale.

Question 51

Use of immobilised enzymes in the production of pure samples of L-amino acids?

Answer 51

When scientists synthesise amino acids, they end up with a mix of L and D forms. The enzyme aminoacylase seperates them. Immobilised aminoacylase is used for the industrial production of pure samples of L amino acids, which can be used for many purposes in the production of animal and human food as well as dietary supplements.

Question 52

Use of immobilised enzymes in conversion of acrylonitrile to acrylamide?

Answer 52

Acrylamide is used in industry to produce synthetic polymers eg plastics, which have many uses. In industry, immobilised nitrilase is used to convert acrylonitrile to acrylamide.

Question 53

Formula to work out number of cells in a population

Answer 53

Initial number of cells x 2 to the power of the number of divisions.