6.4 - E - Cloning And Biotechnology

Question 1

How many examples of natural clones in animals and plants can you name?

Answer 1

Tubers, runners, corms, rhizomes, bulbs, suckers, leavers - these happen using a process called vegetative propagation.
Identical twins.

Question 2

Evaluate cloning

Answer 2

+ All offspring have genes to survive in environment.
+ Quick.
+ Possible when sexual reproduction fails/isn’t possible.
- No genetic variation.
- Overcrowding.
- Selection isn’t possible.
- If the environment changes to be less advantageous, the whole population is susceptible.

Question 3

Define vegetative propogation.

How do you think this is possible?

Answer 3

The production of structures in an organism that can grow into new organisms, genetically identical to the parent (clones).
Many parts of the plants contain tissues that have not differentiated, so can divide to form a range of different cell types.

Question 4

Explain runners, rhizomes and suckers as examples of vegetative propagation

Answer 4

Grow horizontal stems called runners or stolens if on surface of ground. Rhizomes in underground. Suckers are new stems that grow from roots of a plant. May be close to the base of an older stem or could be some distance away.

Question 5

Explain bulbs as an example of vegetative propagation

Answer 5

They are an over-wintering mechanism for many perennial monocotyledonous plants. The bulbs consist of an underground stem from which grow a series of fleshy leaf bases. They also have an apical bud, which grow into a new plant in spring.

Question 6

Explain corms as an example of vegetative propagation

Answer 6

Often mistaken for bulbs. They’re solid, not fleshy. It’s an underground stem with scaly leaves and buds.

Question 7

Explain leaves as an example of vegetative propagation

Answer 7

The Kalanchoe plant reproduces asexually, as clones grow on the lead margins. The immature plants drop off the lead and take root.

Question 8

Explain tubers as an example of vegetative propagation

Answer 8

Another type of underground stem. Potatoes are tubers. One potato will grow into one or more plants. Each new plant can then produce many new tubers (potatoes) later the year.

Question 9

Describe how to take plant cuttings as an example of a simple artificial cloning technique

Answer 9

The stem is cut at a node (two leaf joints).
Remove bark if present to avoid the formation of a callus.
Add rooting powder depending on plant species (some will
take root less easily).
The cut end of the stem is buried into soil.
New roots will begin to grow into the soil.
This process is also possible from root cuttings, scion cuttings (in
woody twigs) and leaf cuttings.

Question 10

Which process is the basis of asexual reproduction?

Answer 10

Mitosis

Question 11

Why is asexual reproduction faster than sexual reproduction?

Answer 11

Does not require the development of sex organs or specialised haploid gametes. The organism does not need to release male gametes nor do cells need to be transferred to another individual.

Question 12

What is a clone?

Answer 12

Genetically identical organisms or cells

Question 13

Evaluate artificial cloning

Answer 13

+ quick.
+ useful for those who can’t breed sexually.
+ genetically identical.
+ no viruses.
- labour intensive.
- expensive.
- culture can fail due to microbial contamination.

Question 14

What is a node?

Answer 14

Where 2 leaves are joint

Question 15

Define micropropogation

Answer 15

Growing large numbers of new plants from meristem tissue taken from a sample

Question 16

Explain micropropogation

Answer 16

Tissue from apical buds (an explant) taken because it is meristematic and therefore undifferentiated and can still undergo mitosis.
Surface is cleaned using sterilising agent to ensure aseptic conditions so that no bacteria can grow as it could compete with the plant tissue.
Explant is placed onto nutrient medium to encourage mitosis this produces a callus (mass of undifferentiated cells).
The callus is subdivided and placed in a new nutrient medium which will encourage differentiation of tissue.
The callus cells will grow into plantlets and can be then placed sterile soil. These small clumps grow, divide and differentiate. This is achieved by moving cells into a different growth media. They contain a ratio of 100 auxin: 1 cytokinin. The second medium has 4:1.
Once plantlets form, move to greenhouse.

Question 17

What is found in a callus?

Answer 17

Auxins ‐ stimulate formation of root hairs.
Cytokinins ‐ stimulate shoot growth.
Magnesium ‐ helps the plant make chlorophyll.
Nitrates needed for protein synthesis.
Sucrose ‐ converted to glucose for respiration.

Question 18

List advantages of clones rather than seeds

Answer 18

Genetically identical.
Maintains favourable characteristics.
Quicker to produce.
More likely to survive.
More produced.
Disease free.
Easily genetically manipulated.
Can be used for cloning infertile plants.
Easy to transport/store.

Question 19

List disadvantages of clones rather than seeds

Answer 19

Genetically identical ‐ all susceptible to same diseases.
Loss in genetic diversity.
Farmers have to buy the plants from suppliers.
Patented property ‐ high cost ‐ can’t replicate them yourself to sell (expensive to do, e.g. training, sterile conditions, equipment costs).

Question 20

What is grafting?

Answer 20

Taking a cutting from a plant attached to the stem of another.
This then grows and they are genetically identical to each other.
The vascular tissue joins (inosculation) and this is stimulated in order to grow by mitosis. The stems have to be cut at an angle.
Grafting is also known as artificial propogation.

Question 21

State and define the 2 methods which can be used to artificially clone animals.
What are these methods called? Why?

Answer 21

Embryo twinning - splitting an embryo to create 2 genetically identical embryos.
Somatic cell nuclear transfer (SCNT) - a technique that involves transferring the nucleus from a somatic cell to an egg cell.
Reproductive cloning - they make new offspring.

Question 22

Define enucleation

Answer 22

Removal of the cell nucleus

Question 23

Explain the steps in embryo splitting

Answer 23

A zygote is created by IVF.
It is allowed to divide by mitosis to form a small ball of cells.
The cells are separated and allowed to continue dividing.
Each small mass of cells is placed into the uterus of a surrogate mother.

Question 24

State 2 uses of embryo twinning

Answer 24

Cloning ‘elite’ farm animals.

Scientific research.

Question 25

Explain the steps in SCNT

Answer 25

An egg cell is obtained and is enucleated.
A normal body cell (somatic cell) from the adult to be cloned is isolated and may have the nucleus removed.
The complete adult somatic cell or its nucleus is fused with the empty egg cell by applying an electroshock (electrofusion).
The shock also triggers the egg cell to start developing, as though it had just been fertilised.
The cell undergoes mitosis to produce a small ball of cells.
The young embryo is placed into the uterus of a surrogate.

Question 26

What 3 things do you do when collecting eggs for cloning (or IVF)?

Answer 26

Treated with hormone (FSH).
Superovulation.
Collect eggs from ovaries.

Question 27

Why is a clone not entirely genetically identical to the nucleus donor?

Answer 27

DNA is also found in mitochondria.
Only get DNA from nucleus in clones (not their cytoplasm).
Mitochondrial DNA is found in cytoplasm.

Question 28

How could surrogates be prepared for implantation of an embryo?

Answer 28

Hormone treatments.
To prepare uterus for implantation by causing the lining to thicken so there is an increased blood supply for the placenta.

Question 29

Define therapeutic cloning. Include examples.

Answer 29

New tissues and organs can be grown and replaced in patients where damaged e.g. skin grafts, pancreatic cells producing insulin, spinal cord damage.

Question 30

List the reasons how cloning can help preserving a species

Answer 30

Increases rate of reproduction.
Does not require species’ eggs.
So does not require fertile female.
Does not require female for pregnancy / uses surrogate.
Female not put at risk in, travel / mating / pregnancy.
Successfully formed embryo can be, subdivided / cloned.
Can use adult cells from all existing animals to maintain diversity.

Question 31

List 3 types of people to whom therapeutic cloning is useful

Answer 31

Skin can be grown in vitro to act as a graft over burned areas.
Cloned cells have been used to repair damage to the spinal cord of a mouse and to restore the capability to produce insulin in the pancreas.
There is the potential to grow whole new organs to replace diseased organs.

Question 32

Give points for artificial cloning in animals in the argument

Answer 32

Can produce a whole herd of animals with a high yield or showing an unusual combination of characteristics.
Produces genetically identical copies of very high value individuals retaining the same characteristics.
Using genetically identical embryos and tissues for scientific research allows the effects of genes and hormones to be assessed with no interference from different genotypes.
Testing medicinal drugs on cloned cells and tissues avoids using animals or people for testing.
Can produce cells and tissues genetically identical to the donor, for use in repairing damage caused by disease or accidents.
Individuals from an endangered species can be cloned to increase numbers.

Question 33

Give points against artificial cloning in animals in the argument

Answer 33

Lack of genetic variation may expose the herd to certain diseases or pests. Animals may be produced with little regard for their welfare, which may have undesirable side effects such as meat-producing chickens that can’t work.
The success rate of adult cell cloning is very poor and the method is a lot more expensive than conventional breeding. Cloned animals may be less healthy and have shorter life spans.
There are ethical issues regarding how long the embryo survives and whether it is right to create a lift simply to destroy it.
Repopulation by cloning doesn’t increase genetic diversity.

Question 34

Define biotechnology

Answer 34

The use of living organisms or parts of living organisms or parts of living organisms in industrial processes. This could be to produce food, drugs or other products.

Question 35

What are the 4 main products produced from biotechnology?

Answer 35

Food
Enzymes
Drugs
Other products

Question 36

List the advantages of using microorganisms in biotechnology

Answer 36

Microorganisms are relatively cheap and easy to grow.
In most cases, the production process takes place at lower temps than would be required to make the molecules by chemical engineering means. This saves fuel and reduces costs.
The production process can take place at normal atmospheric pressure, which is safer than using chemical reactions that may require very high pressure for successful manufacture of certain molecules.
The process isn’t dependent on climate - can take place anywhere in the world with the resources to build and run suitable equipment.
Microorganisms have a short life cycle and reproduce quickly. Some microorganisms may reproduce as often as every 30 mins under ideal conditions. Therefore, a large population can grow very quickly inside the fermenter (reaction vessel).

Question 37

What are the topics you need to know about regarding using biotechnology to make food?

Answer 37

Yoghurt
Cheese
Baking
Alcoholic drinks
Single‐cell protein (SCP)

Question 38

How is cheese made?

Answer 38

Milk is pre-treated with a culture of bacteria called lactobacillus - this can produce lactic acid from lactose.
Once acidified, the milk is mixed with rennet which contain the enzyme rennin, which is found in the stomach of young mammals. It coagulated the milk protein casein in the presence of calcium ions:
Kappa, which keeps the casein in solution, is broken down. This makes the casein insoluble.
The casein is precipitated by the action of calcium ions, which bind the molecules together.
The resulting solution is called curd and is separated from the liquid component (whey) by cutting, stirring and heating. The bacteria continue to grow, producing more lactic acid. The curd is then pressed into moulds.

Question 39

Explain the 3 key steps for baking bread in biotechnology

Answer 39

Mixing - the ingredients are mixed by kneading which creates a dough.
Proving/fermenting - the dough is left in a warm place to rise for 3 hours while the yeast respires anaerobically. This produces carbon dioxide bubbles, causing the bread to rise.
Cooking - the risen dough is baked in the oven. Any alcohol evaporated during this process.

Question 40

Explain how yogurt is made using biotechnology

Answer 40

Yogurt is milk that has undergone fermentation by 2 bacteria. The bacteria convert lactose to lactic acid. The acidity denatures the milk protein, causing it to coagulate. The bacteria partially digests the milk, making it easy to digest. Fermentation also produces the flavours of yogurt.

Question 41

Explain how alcoholic beverages are made using biotechnology

Answer 41

An alcohol is a compound containing carbon, hydrogen and oxygen. The fruit or grain is added alongside yeast and placed in a vat with optimum conditions - 27°C, pH7, no oxygen. The anaerobic conditions causes the ethanol fermentation pathway to occur. The mixture of ethanol and water can be tapped out at regular intervals to obtain the desired alcoholic beverage. The longer the alcohol is kept in the vat, the greater the concentration of ethanol and therefore the ABV increases.
Grapes contain yeast in their skin so, when they are crushed, the yeast is released and they can undergo anaerobic respiration. Grams such as barely may be used to produce beer. As the grains germinate, starch is converted to maltose and the availability of substrate molecules increases.

Question 42

What is single-cell protein used for?

Answer 42

Microorganisms have been used to manufacture protein that is used directly as food.
The organism most frequently used is the fungus Fusarium venenatum
The fungal protein or mycoprotein is knows as single-cell protein (SCP)
The best known example of a mycoprotein is Quorn.
It is marketed as a meat substitute for vegetarians and a healthy option for non- vegetarians as it contains no animal fat or cholesterol.

Question 43

Explain the problem with SCP production

Answer 43

When using the microorganism such as Kluyveromyces, Scytalidium and Candida there is potential for problems.
These fungi can produce protein with a similar amino acid profile to animal and plant protein.
They can grow on almost any organic substrate, including waste materials such as paper and whey (curdled milk where the curdles have been removed).

Question 44

Evaluate SCP production

Answer 44

+ Microorganisms have high rate of multiplication.
+ Not dependent on climate.
+ Land requirements is low and is ecologically beneficial.
+ Strains with high yield and good composition can be selected or produced relatively easily.
- Possibility of presence of toxins or carcinogenic compounds may lead to some serious health problems in humans and animals.
- Very expensive procedure because it needs high level of sterility control in laboratory.
- High nucleic acid content of microbial biomass may lead to poor digestibility, gastrointestinal problems and also some skin reactions in humans. Occasionally, it can lead to kidney stone formation and gout.

Question 45

Evaluate microorganisms and food production in regard to biotechnology

Answer 45

\+ production speed is very fast,
\+ production can easily be altered to meet demand,
\+ no animal welfare/ethical issues,
\+ production not affected by climate,
\+ little land required,
- downstream processing,
- risk of culture infection.

Question 46

Describe the conditions which need to be controlled in batch and continuous fermentation processes to maximise product yield

Answer 46

Carbon, nitrogen, vitamins and minerals needed for growth are inserted.
Sterile air pumped in for aerobic respiration (avoiding contamination).
Cooling water jacket to keep optimum temperature for enzymes.
pH and temp monitors to ensure optimums for enzymes.
Motor stirrer for aeration.

Question 47

Explain batch fermentation

Answer 47

Slow growth and easy to set up and maintain.
Contamination = loss of just one batch.
Less efficient.
At end products removed and tank emptied. Process started again.
Microorganism starter population mixed with fixed quantity of nutrients at start ‐ no more added.
Produces secondary metabolites after log phase (during stationary phase) because nutrients deplete e.g. Penecillium making antibiotic Penicillin.

Question 48

Explain continuous fermentation

Answer 48

Produces primary metabolites during log phase because nutrients do not deplete and culture stays in log phase.
e.g. Insulin from E.coli.
Growth is fast but it’s quite difficult to set up and maintain.
Contamination = loss of lots of product.
More efficient.
Nutrients and products added and removed from culture continuously.

Question 49

Describe the standard growth curve

Answer 49

4 stages:
Lag phase - bacteria start to grow.
Exponential phase - population doubles every 20 minutes.
Stationary (aka log) phase - growth stops (theoretical growth is exponential).
Death phase - bacteria die faster than they multiply.

Question 50

What are metabolites?

What are the 2 types?

Answer 50

Products of metabolic reactions.

Primary and secondary.

Question 51

Explain primary metabolites

Answer 51

Produced during normal (log) growth phase.
Essential for normal cell growth/reproduction
> match growth in population (i.e. same pattern as growth curve).

Question 52

Explain secondary metabolites

Answer 52

Not produced during normal (log) growth phase.
Produced after normal growth phase.
Not essential for normal cell growth/reproduction
> does not match the growth in population.
> most antibiotics are secondary metabolites.

Question 53

Explain the importance of maintaining aseptic techniques in fermenters

Answer 53

To avoid unwanted presence of microbes,
So no competition for nutrients.
So no decrease in yield,
So no contamination of product.

Question 54

Define and explain bioremediation.

What does it involve?

Answer 54

The use of microorganisms to clean the soil and underground water on polluted sites. The organisms convert the toxic pollutants to less harmful substances.
It involves stimulating the growth of suitable microbes that use the contaminants as a source of food. It requires the right conditions for the growth of microorganisms which are:
Available water,
A suitable temperature,
A suitable pH.

Question 55

What are the advantages of bioremediation?

Answer 55

Uses natural systems,
Less labour and equipment is required,
Treatment in situ,
Few waste products,
Less risk of exposure to clean-up personnel.