Cloning and Biotechnology

Question 1

What is cloning?

Answer 1

Cloning is the process of producing genetically identical cells or organisms from the cells of an existing organism. Cloning can occur naturally in some plants and animals but it can also be carried out artificially.

Question 2

What is vegetative propagation?

Answer 2

Vegetative propagation is the production of plant clones from non-reproductive tissues.

Question 3

What are rhizomes and what plant uses this technique?

Answer 3

Rhizomes are stem structures that grow horizontally underground away from the parent plant. They have nodes from which new shoots and roots can develop.
e.g bamboo

Question 4

What are stolons/runners and what plant uses this technique?

Answer 4

Stolons are similar to rhizomes. The main difference is that they grow above ground on the surface of the soil. New shoots and roots can either develop from nodes or form at the end of the stolon.
e.g strawberries

Question 5

What are suckers and what plant uses this technique?

Answer 5

Suckers are shoots that grow from sucker buds present on the shallow roots of a parent plant.
e.g elm trees

Question 6

What are tubers and what plant uses this technique?

Answer 6

Tubers are large underground plant structures that act as a food store for the plant. They’re covered in eyes. Each eye is able to sprout and form a new plant.
e.g potatoes

Question 7

What are bulbs and what plant uses this technique?

Answer 7

Bulbs are also used in underground food stores by some plants. New bulbs are able to develop from the original bulb and form new individual plants.
e.g onions

Question 8

What are some natural methods of vegetative propagation?

Answer 8

• taking cuttings
• grafting
• layering

Question 9

How would you take and grow a cutting from a stem?

Answer 9

1. use a scalpel or sharp secateurs to take a cutting, between 5 and 10cm long from the end of a stem of your parent plant
2. remove the leaves from the lower end of your cutting, leaving just 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 growth medium
5. provide the cutting with a warm and moist environment by covering the pot with a plastic bag or by putting it in a propagator
6. when your cutting has formed its own roots and is strong enough, you can plant it elsewhere to continue growing

Question 10

How can plants be artifically cloned using tisuse culture?

Answer 10

• cells are taken from the original plant that’s going to be cloned
• cells from the stem and root tips are used because they’re stem cells
• the cells are sterilised to kill any microorganisms- bacteria and fungi compete for nutrients with the plant cells, which decrease their growth rate
• the cells are placed on a culture medium containing plant nutrients and growth hormones
• when the cells have divided and grown into a small plant they’re taken out of the medium and planted in soil

Question 11

When is tissue culture used?

Answer 11

• it is used to clone plants that don’t readily reproduce or that are rare
• it is used to grow whole plants from genetically engineered plant cells

Question 12

What is micropropagation?

Answer 12

Micropropagation is when tissue culture is used to produce lots of cloned plants very quickly. This technique is used extensively in horticulture and agriculture to produce fields full of a crop that has been genetically engineered to be pest-resistant.

Question 13

What are some of the arguments for artificial plant cloning?

Answer 13

• desirable genetic characteristics are always passed on to clones. This doesn’t always happen when plants produce sexually
• tissue culture allows plants to be reproduced in any season because the environment is controlled
  Tissue culture requires less space than conventional growing methods to produce the same number of plants.
• it produces lots of plants very quickly compared to the time it would take to grow them for seeds.

Question 14

What are some of the arguments against artificial plant cloning?

Answer 14

• undesirable genetic charactericsitcs are always passed on to clones
• cloned plant populations have no genetic variability, so a single disease could kill them all.
• 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
• contamination by microorganisms during tissue culture can be disastrous and result in a complete loss of the plants being cultured.

Question 15

How can animal clones occur naturally?

Answer 15

During sexual reproduction, once an egg has been fertilized, 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. E.g identical twins

Question 16

How can you carry out artificial embryo twinning?

Answer 16

1. an egg cell is extracted from a female cow and fertilized in a petri dish
2. the fertilized egg is left to divide at least once forming an embryo in vitro
3. next, the individual cells from the embryo are separated and each is put into a separate petri dish. Each cell divides and develops normally, so an embryo forms 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 17

How would you carry out somatic cell nuclear transfer?

Answer 17

1. a somatic cell is taken from sheep A. The nucleus is extracted and kept.
2. An oocyte is taken from sheep B. Its nucleus is removed to form an enucleated oocyte.
3. The nucleus from sheep A is inserted into the enucleated oocyte- the one from sheep B
4. The nucleus and the enucleated oocyte are fused together and stimulated to divide. This produces an embryo.
5. then the embryo is implanted into a surrogate mother and eventually a lamb is born that is a clone of sheep A

Question 18

What are some of the uses of animal cloning?

Answer 18

• you can test new drugs
• save endangered animals from extinction
• can be used in agriculture to maximise yields of milk etc/ continue desirable characteristics
• can produce lots of genetically modified animals
• can make tissues and cells to produce tissues needed for patients with diseases

Question 19

What are some arguments for animal cloning?

Answer 19

• desirable genetic characteristics are always passed on to clones
• infertile animals can be reproduced
• increasing the population of endangered species helps to preserve biodiversity
• animals can be cloned at any time, you don’t have to wait until the breeding season
• cloning can help us to develop new treatments for disease

Question 20

What are some arguments against animal cloning?

Answer 20

• animal cloning is very difficult, time-consuming and expensive
• there is no genetic variability in cloned populations so undesirable genetic characterisitcs are always passed onto clones
• some evidence suggests that clones may not live as long
• using cloned human embryos is a destructive process if used as a source for stem cells which raises ethical concerns.

Question 21

What is biotechnology

Answer 21

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

Question 22

Why do we use microorganisms in biotechnology?

Answer 22

• Their ideal growth conditions can be easily created
• due to a short life cycle they can grow rapidly so products can be made quickly
• they can be grown on a range of inexpensive materials
• they can be grown at any time of the year

Question 23

Why does biotechnology also use enzymes?

Answer 23

• they can be used in industry contained within the cells of organisms
• enzymes are also contained within cells called isolated enzymes
• naturally secreted enzymes are cheaper to use because it can be expensive to extract enzymes from cells.

Question 24

What is the role of microorganisms in making beer?

Answer 24

To make beer, yeast is added to a type of grain and other ingredients. The yeast respires anaerobically using the glucose from the grain and produces ethanol and CO2.

Question 25

What is the role of microorganisms in making baking?

Answer 25

Yeast is also the organism that makes bread rise. The CO2 produced by fermentation of sugars in the dough makes sure it doesn’t stay flat. Many flat breads, like tortillas, are made without yeast.

Question 26

What is the role of microorganisms in making Cheese?

Answer 26

Cheese production used to rely on a substance called rennet. Rennet contains the enzyme chymosin, which clots the milk- a key process in cheese making. Traditionally we used to get chymosin by extracting rennet from the lining of calves’ stomachs, but now chymosin can be obtained from yeast cells that have been genetically modified to produce the enzyme. Cheesemaking also involves lactic acid bacteria. These bacteria convert the lactose in milk into lactic acid, which makes it turn sour and contributes to its solidifiying. The production of blue cheeses also involves the addition of fungi to make the characteristic of blue veins.

Question 27

What is the role of microorganisms in making yogurt?

Answer 27

Just like cheese making, yogurt production involves the use of lactic acid bacteria to clot the milk and cause it to thicken. THis creates a basic yogurt product and then any flavors and colors are added.

Question 28

What is the role of microorganisms in making penicillin?

Answer 28

In times of stress, fungi from the 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 we produce it on a massive scale. The fungus is grown under stress in industrial fermenters and the penicillin produced is collected and processed to be used in medicine.

Question 29

What is the role of microorganisms in making insulin?

Answer 29

Insulin is a hormone that is crucial for treating people with type 1 diabetes. Insulin is made from genetically modified bacteria that have had the gene for human insulin production inserted into their DNA. These bacteria are grown in an industrial fermenter on a massive scale and the insulin produced is collected and purified.

Question 30

What is the role of microorganisms in bioremediation?

Answer 30

Bioremediation is a posh name for the process of using organisms to 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 them to multiply and thrive. These bacteria break down the pollutants into less harmful products, cleaning up the area. For example, bioremediation using bacteria hasbeen used to clean up oil spills at sea.

Question 31

What are the advantages of using microorganisms in food production?

Answer 31

• they can be used to make single-cell proteins using many different organic substrates including waste materials such as molasses. Production of single-cell protein couls actually be used as a way of getting rid of waste products.
• they can be grown quickly, easily, and cheaply. Production costs are low because they have simple growth requirements that can be grown on waste products and less land is required in comparison to growing crops of rearing livestock.
• they can be cultured anywhere with the right equipment which could help tackle malnutrition in developing countries
• single cell proteins are often considered a healthier alternative to animal protein.

Question 32

What are the disadvantages of using microorganisms in food production?

Answer 32

• the conditions needed to grow one microorganism could promote the growth of other microorganisms which could be dangerous so expensive steps need to be taken to prevent this
• people may not like the idea od eating food that has been grown using waste products
• single cell protein doesn’t have the same texture or flavor as real meat
• if single-cell protein is consumed in high quantities, health problems could be caused due to high levels of uric acid released when large amounts of amino acids are broken down.

Question 33

What is batch fermentation

Answer 33

Batch fermentation is when microorganisms are grown in individual batches in a fermentation vessel, when one culture ends it is removed, and then a different batch of microorganisms is grown in the vessel. This is also called closed culture.

Question 33

What is culture?

Answer 33

A culture is a population of one type of microorganisms that has been grown under controlled conditions.

Question 34

What is continuous fermentation?

Answer 34

This is where the microorganims are continually growtn in a fermentation vessel without stopping. Nutrients are put in and waste products are taken out.

Question 35

How is pH regulated in fermentation?

Answer 35

Constantly monitored by a pH probe
optimum pH allows enzymes to work optimally

Question 36

How is temperature regulated in fermentation?

Answer 36

Kept constant by a water jacket that surrounds the entire vessel
optimum temp allows enzymes to work optimally

Question 37

How are nutrients regulated in fermentation?

Answer 37

Paddles constantly circulate fresh nutrient medium around the vessel
ensures that the microorganisms always have access to their required nutrients.

Question 38

How is oxygen regulated in fermentation?

Answer 38

Sterile air is pumped into the vessel when needed.
Makes sure that the microorganisms always have oxygen needed for respiration.

Question 39

How are sterile conditions regulated in fermentation?

Answer 39

Superheated steam sterilizes the vessel after each use.
Kills any unwanted organisms that my complete with one being cultured

Question 40

What is a closed culture?

Answer 40

A closed culture is when growth takes place in a vessel that is isolated from the external environement

Question 41

What is the lag phase in a standard growth curve?

Answer 41

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

Question 42

What is the exponential phase in a standard growth curve?

Answer 42

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

Question 43

What is the stationary phase in a standard growth curve?

Answer 43

The population size stays level because the death rate of the microorganisms equals their reproductive rate. Microorganisms die because there isn’t enough food and poisonous waste products build-up

Question 44

What is the decline phase in a standard growth curve?

Answer 44

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

Question 45

What is the equation for microorganism population?

Answer 45

N = N (original) x 2 ^n

Question 46

How would you culture microorganisms in the lab?

Answer 46

• use an agar plate
• transfer microorganisms from the sample to the plate using a sterile implement like a wire inoculation loop or a sterile pipette and spreader
• you then incubate the plates and allow the microorganisms to grow
• nutrients can then be added to the agar to help improve the growing conditions

Question 47

What is the purpose in using aseptic techniques when culturing microorganisms?

Answer 47

• prevent contamination
• could get imprecise results
• could be costly if whole contaminated cultures need to be thrown away

Question 48

What are some important aseptic techniques you must use when culturing microorganisms?

Answer 48

• regularly disinfect work surfaces
• work near the bunsen flame
• sterile instrument
• minimize agar plate exposure time
• sterilize glassware
• wear a lab coat

Question 49

What is a spectrophotometer?

Answer 49

It is a machine that measures the turbidity of the broth. Higher tubidy means that more cells are present and, therefore more replication has takne place.

Question 50

How would you measure the effect of temperature on the growth of bacteria?

Answer 50

1)
You should be supplied with a sample of bacteria (e.g. E. coli) in broth. Using a
sterile pipette, add a set volume (e.g. 0.1 cm’) of your sample to an agar plate.
Discard your pipette safely after use.
2)
Spread the broth across the entire surface of the agar using a sterile plastic spreader.
Discard the spreader safely after use.
Put the lid on the agar plate and lightly tape it shut using two small pieces of tape.
4)
Repeat steps 1-3 so that you have six plates in total.
5)
Place three plates in a fridge at 4 °C and put three in an incubator at 25 °C.
If you don’t have access to an incubator, just leave the plates at room temperature, somewhere where the temperature is most likely to remain constant. The plates should be incubated upside down. This stops any condensation forming on the lid from dropping onto the agar.
6)
Put another lidded agar plate in each of the two different temperature locations these plates should be uncultured (i.e. you shouldn’t have added any bacteria to them).
These plates will act as negative controls (nothing should grow on them).
Leave all the plates for the same amount of time (e.g. 48 hours) then observe the results.
8)
If bacterial growth has occurred, you should see colonies of bacteria on the surface of the agar.
Count the number of colonies that have formed on each plate and record your results in a table.
10) Work out the mean number of colonies formed at each temperature.

Question 51

Why are immobilised enzymes needed?

Answer 51

• isoltated enzymes in industry can become mixed in with the products of a reaction
• the products then need to be separted from this mixture, which can be complicated and costly
• this is avoided in large scale production by using immobilised enzymes- enzymes that are attached to an insoluble material so they can’t become mixed with the products

Question 52

How can you immobilise enzymes?

Answer 52

• they can be encapsulated in jelly-like alginate beads, which act as a semi-permeable membrane
• they can be trapped in a silica gel matrix
• they can be covalently bonded to cellulose or collagen fibers

Question 53

How are immobilised enzymes used in industry?

Answer 53

In industry, the substrate solution for a reaction is run through a column of immobilised enzymes. The active sites of the enzymes are still available to catalyse the reaction but the solution flowing out of the column will only contain the desired product

Question 54

What are the advantages of using immobilized enzymes in the industry?

Answer 54

• columns of immobilized enzymes can be washed and reused, this reduces the cost of running a reaction on an industrial scale because you do not have to keep buying new enzymes
• the product isn’t mixed with the enzymes, no money or time is spent separating them out
• immobilised enzymes are more stable than free enzymes, they’re less likely to denature in high temperatures or extremes of pH

Question 55

What are the disadvantages of using immobilized enzymes in the industry?

Answer 55

• extra equipment is required, which can be expensive to buy
• immobilized 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 production
• The immobilization of the enzymes can sometimes lead to a reduction in the enzyme activity because they cant freely miz with their substrate.

Question 56

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

Answer 56

Some people are unable to digest lactose because they don’t produce enough of the enzyme lactase. Lactase breaks lactose down into glucose and galactose via a hydrolysis reaction. Industrially, fresh milk can now be passed over immobilised lactase to provide lactose free milk for use in the production of lactose-free dairy products.

Question 57

How are immobilized enzymes used to produce semi-synthetic penicillins?

Answer 57

Penicillin is a useful antibiotic, but some bacteria have become penicillin-resistant. Semi, synthetic penicillins can now be produced, which have the same antibiotic properties as natural penicillin but are effective against penicillin-resistant organisms. Immobilized penicillin acylase enzyme is used in their production.

Question 58

How are immobilized enzymes used to produce dextrins to glucose?

Answer 58

Glucose and glucose syrup are used in massive amounts in industry, e.g. they are used in the food industry to sweeten and thicken foods. Glucose can be derived from starchy goods, such as corn and potatoes, with the help of immobilized enzymes. Starch breaks down into dextrins, which are then broken down into glucose by the immobilized enzyme glucoamylase.

Question 59

How are immobilized enzymes used to convert glucose to fructose?

Answer 59

Fructose is a sugar that is much sweeter than glucose. It is used as a sweetener in food, using fructose rather than glucose means that less sugar is needed to obtain the same level of sweetness in our foods. Immobilized glucose isomerase is used to convert glucose to fructose on an industrial scale.

Question 60

How are immobilized enzymes used to produce pure samples of L-amino acids?

Answer 60

Amino acids have two chemical forms. Most amino acids utilized by the body need to be in the L form. Scientists can chemically synthesize amino acids, but end up with a mix of L and D forms. The enzyme aminoacylase separates them. Immobilized 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 in dietary supplements.