6.2.1 Cloning and Biotechnology

Question 1

What is a clone?

Answer 1

A genetically identical copy of an individual organism, cell or single gene.

Question 2

How do plants produce natural clones? (5)

Answer 2

Due to their nature to reproduce asexually:
a structure is propagated from a perennating organ to form a clone independent from parents.

Bulbs+ tubers: underground structures produced from the swelling of a leaf or stem base. e.g Daffodils and potatoes.

Runners: when a lateral stem grows away from the parent plant and develops a new root where a vertical
stem grows. e.g strawberries

Rhizomes: horizontal stems develop buds which form new vertical shoots that grow into new plants.

Question 3

Fragmentation

Answer 3

When a clone plant is produced from a small part of the original plant.

Question 4

Tissue culture

Answer 4

Cloning of cells from a small group of genetically identical cells to form a mass of similar cells.

Explants are placed in growth medium which allow cells to grow by mitosis and differentiate into the different organs of a plant.

Question 5

How is stem cuttings used in horticulture?

Answer 5

Cuttisngs obtained are dipped in rooting powder which contain auxins.

This grows new plant faster without the need for seeds and guarantees quality of plant created.

Question 6

Describe the steps in micropropagation? (6)

Answer 6

1. Original plant material is cut to make explants. The tissue is usually the meristem or axial buds.
2. Sample is sterilised using ethanol and bleach so that it is free from disease caused by bacteria or fungi
3. Following steps are now under aseptic techniques.
4. Explant is placed into a growth medium (agar jelly) which contains vital nutrients: glucose, phosphates, nitrates and amino acids. As well as hormones that stimulate mitosis: auxins, cytokines.
5. Cells divide to form a small massed called a callus. This is then sub-divided and placed into a new medium containing different concentrations of auxin and cytokines.
6. Callus differentiates into tissues and organs to form a plantlet. This is then transferred to compost where it grows into a plant.

Question 7

Callus

Answer 7

A mass of undifferentiated cells that are totipotent.

Question 8

What are the advantages of cloning plants. (5)

Answer 8

Allows rapid production of crops with known qualities, which is quicker than planting with seeds.

Plants grown are disease-free.

Desirable qualities of a plant can be selected and reproduced. e.g seedless fruits.

Rare plants can be reproduced and conserved.

Infertile plants can also be reproduced.

Question 9

Disadvantages of cloning plants. (5)

Answer 9

Monoculture: all plants will be susceptible to the smae disease/ pest. Allows disease/pests to infect all and spread rapidly.

Expensive: more technology and skilled workers require.

Gene pool is decreased so this leads to decreased variation. Prevents evolution from occurring

Infection of a virus means that all clones will also be infected.

Microbial infection stops the whole process, if aseptic techniques fail.

Question 10

Immobilised ezyme

Answer 10

Enzyme fixed in place by attaching it to an inert, insoluble material.

Question 11

Methods of immobilising enzymes (4)

Answer 11

Adsorption: mixing enzymes with adsorbing agents. This causes enzymes to form ionic/ hydrophobic links to agent.

Covalent bonding: enzymes are covalently bonded to an insoluble material using a cross-linking agent.

Entrapment: enzymes are trapped in alginate gel beads or cellulose fibres.

Membrane separation: enzyme is separate from substrate through a semi-permeable membrane.

Question 12

Advantages of using immobilised enzymes

Answer 12

Enzymes can be reused as they don’t ‘run out’

Enzymes can be easily separate from product compared to separating product from undesired waste molecules.

Provides increased resistance to changes in pH and temperature.

Question 13

Disadvantages of immobilised enzymes.

Answer 13

Some enzymes can become dislodged and lost. Making the process less efficient.

Due to fixed position, less movement disallows less collisions between substrates.

Question 14

Aminoacylase

Answer 14

Produces pure samples of L-amino acids

Used as building blocks for making pharmaceutical molecules

Question 15

Why is I useful to use micro-organisms in biotechnology?

Answer 15

Can be grown rapidly in mass sizes, which makes it cheaper.

Organisms have a short life cycle, so reproduction is rapid.

Organisms can be genetically engineered to produce desires product.

Organisms can be grown on waste products.

Avoids the ethical problem of using animals.

Question 16

Disadvantage of using micro-organisms in biotechnology.

Answer 16

Some people do not enjoy food being grown from microbes or from waste material.

Food grown might not taste the same.

Fermentation can be contaminated

Question 17

Using micro-organisms to make yoghurt

Answer 17

Bacteria is used: lactobacillus.

Milk is heated at first to denature proteins and form curds.

Bacteria is then added at cooler temperature.

Fermentation occurs when bacteria uses lactose in milk.

Question 18

Using micro-organisms in making cheese and blue cheese.

Answer 18

Bacteria: lactococcus, lactobacillus.
Fungus: penicillium (blue cheese)

Milk is separated to curds using rennin. Bacteria ferments sugar to lactic acid.

In blue cheese, mould is added to give its ‘blue veins’

Question 19

Using micro-organisms to make bread.

Answer 19

Fugue: yeast

Yeast is added as a rising agent

Question 20

Micro-organisms

To make alcohol

Answer 20

Fungus: yeast

Yeast turns sugar to ethanol and CO2

Question 21

Using micro-organisms to make mycoprotein

Answer 21

Fungus: Fusarium

In fermentation, the protein is made.

This has high protein content and a low fat and saturate fat content.

Also alternate protein source for vegans/vegetarians.

Question 22

Using micro-organisms to produce human insulin

Answer 22

Bacteria: recombinant DNA technology

Insulting gene is inserted into bacteria. Bacteria produces insulting rapidly and secretes it.

Question 23

Using micro-organisms to produce penicillin.

Answer 23

Fungus: penicillium

Fungus cells are grown in ‘fed batches’. Under stress they produce the mould.

Question 24

Lactase

Answer 24

Enzyme that breaks down lactose sugar into galactose and glucose.

It can be immobilised to produce lactose free milk for lactose intolerant people.

Question 25

Penicillin acyclase

Answer 25

Enzyme that can be immobilised:
Breaks down penicillin to form a molecule that is used as the main starting block for the preparation of numerous semisynthetic penicillins.

Question 26

Glucoamylase

Answer 26

Enzyme that immobilised.

Converts short-chain carbohydrates (dextrins) into glucose

Used to convert raw starch pulp into glucose

Question 27

Nitrilase

Answer 27

Enzyme that can be immobilised to break down nitriles into carboxylic acids and ammonia.

Question 28

Glucose isomerase

Answer 28

Enzyme that can be immobilised to convert glucose to fructose.

This is used in industry in the production of high fructose corn syrup (HFCS)

HFCS is sweeter than sucrose and is used in diet foods.

Question 29

Vegetative propagation

Answer 29

The form of asexual reproduction where an offspring is formed that is genetically identical to the parent.

Question 30

Somatic cell nuclear transfer. (5)

Answer 30

An artificial method of cloning animals:

1. The individual who is being cloned (A) has its nucleus extracted from an adult cell.
2. A another female’s egg (B) is enucleated. The nucleus is transferred in the enucleated egg.
3. An electric shock is administered to the egg which stimulates mitosis and forms an embryo.
4. The embryo is implanted into a different female’s uterus (C) and is left to develop into a fetus.
5. Offspring born now contains identical DNA to individual A. Mitochondrial DNA is inherited from individual B.

Question 31

Artificial twinning.

Answer 31

1. The female mammal is administered hormones that stimulates super-ovulation to produce a lot of eggs.
2. Female mammal is allowed to naturally reproduce with male.
   OR
   Artificial insemination occurs.
   OR
   The female’s eggs are extracted as well as the male’s sperm. IVF is done in a lab.
3. An embryo will form. When it’s cells are still totipotent, the embryo is split into several embryos.
4. Each embryo is implanted into a different female’s uterus and allowed to develop into a fetus.

Question 32

Advantages of cloning animals.

Answer 32

• Artificial twinning allows high-yielding farm animals to produce more offspring than normal reproduction.
• Artificial twinning ensures that the desired male trait is inherited in all clones.
• Enables rare/ endangered/ extinct animals to be reproduced.
• GM embryos can be replicated so desired traits are in all clones.

Question 33

Disadvantages of cloning animals.

Answer 33

• SCNT is an inefficient process, especially when attempting to clone extinct animals.
• Animals produced have shortened lifespans and can have health complications.
• Lack of genetic variation in a population causes instability, allows susceptibility to disease/ environmental changes.