Cloning and Biotechnology

Question 1

How can we produce natural clones of plants?

Answer 1

Vegetative propagation. Part of a plant is separated, then develops into a new plant genetically identical to the original. English Elm does not produce viable seed, so naturally self-propagates using its roots.

Question 2

How should a plant cutting be taken for cloning?

Answer 2

Stem is cut between the leaf and nodes. Replanted and allowed to grow, sometimes with the use of plant hormones.

Question 3

How can we produce artificial clones of plants?

Answer 3

● Tissue culture; sample placed on various nutrient-containing mediums to encourage cell division and shoot growth.
● Micropropagation; material produced from tissue culture is rapidly multiplied to produce large numbers of plants.

Question 4

Evaluate the use of artificial plant cloning in agriculture.

Answer 4

+ Large number of plants can be produced regardless of weather conditions.
- Reduces genetic variation, making them susceptible to disease.

Question 5

Give an example of natural cloning in animals.

Answer 5

Monozygotic twins; embryo splits during development to produce two genetically identical individuals.

Question 6

How can we produce artificial clones of animals?

Answer 6

● Somatic cell nuclear transfer; differentiated cell from parent fused with an enucleated egg cell. The cell develops into an embryo and can be implanted into a womb.
● Embryo splitting; same process by which twins form, performed artificially.

Question 7

Give arguments surrounding cloning in animals.

Answer 7

+ Quick process suited to the growing population of Earth.
+ Can preserve endangered species.
- Cloned animals often suffer from health
problems.
- Low genetic diversity.

Question 8

Why are microorganisms suited for use in biotechnological processes?

Answer 8

● Rapid growth in a variety of environmental conditions.
● Can be genetically engineered.
● Reduces use of chemicals, beneficial to the
environment.

Question 9

Give some ways microorganisms are used in biotechnological processes.

Answer 9

● Food; baking, brewing, yogurt, cheese ● Medicine; penicillin, insulin
● Environmental; removing pollution
(bioremediation)

Question 10

Give advantages of using microorganisms to produce food for human consumption.

Answer 10

+ Production rate easily varied + Not dependent on climate
+ Long-lasting
+ Uses waste products

Question 11

Give disadvantages of using microorganisms to produce food for human consumption.

Answer 11

• Lack of flavour.
• Proteins must be isolated and purified. - Contains different amino acids to
  animal proteins.

Question 12

Describe the technique that should be used to culture microorganisms.

Answer 12

Aseptic technique; everything must be kept completely sterile so that no unwanted microorganisms are present in the culture.

Question 13

Summarise the three steps of growing microorganisms.

Answer 13

1. Sterilisation; part of the aseptic technique.
2. Inoculation; microorganism introduced to agar
   plate by streaking, seeding, or spreading.
3. Incubation; placed in warm environment for
   24-48 hours to grow.

Question 14

Differentiate between batch and continuous fermentation.

Answer 14

● Batch= closed environment, competition for resources, maintains culture in stationary phase, easy to set up, less efficient.
● Continuous= products continually removed, maintains culture in log phase, difficult to set up, more efficient.

Question 15

How are the growth conditions manipulated to maximise yield?

Answer 15

● Temperature maintained at optimum.
● Sufficient nutrient supply.
● Aerobic conditions to prevent products of
anaerobic respiration.
● pH kept constant to maximise enzyme activity.w

Question 16

Describe the phases of a growth curve of a microorganism in a closed culture.

Answer 16

● Lag= cells increase in size and take in water. Population constant.
● Log= cells divide. Population increases exponentially.
● Stationary= nutrient levels decrease, slowing growth
rate. Population stabilizes.
● Death= toxic metabolites increase to a point that kills
cells. Population declines.

Question 17

Label the phases on this graph of population plotted against time. IMAGE 51

Answer 17

1 - Lag
2 - Log
3 - Stationary
4 - Death

Question 18

Give the formula for bacterial growth.

Answer 18

N = N0 x 2^n
● N = number of bacteria currently in the population
● N0 = number of bacteria in the population at the beginning
● n = number of divisions

Question 19

What is an immobilised enzyme?

Answer 19

An enzyme attached to an inert material in order to restrict its movement and hold it in place during a reaction so that it can be reused.

Question 20

Give methods of immobilising enzymes.

Answer 20

1. Bonding= enzyme binds with support ionically (adsorption) or covalently.
2. Entrapment= enzyme placed in a semi-permeable material that allows diffusion of the substrate and product.
3. Membrane separation= a partially permeable membrane separates enzyme from substrate.

Question 21

Give uses of immobilised enzymes.

Answer 21

● Glucose to fructose conversion.
● Semi-synthetic penicillin production.
● Lactose to glucose/galactose conversion. ● Pure samples of amino acids.
● Dextrins to glucose conversion.

Question 22

Evaluate the use of immobilised enzymes.

Answer 22

+ Product is not contaminated by enzyme, so does not need to be purified.
+ Enzymes can be reused.
+ Enzymes are protected from harsh environment.
- Expensive.
- Reaction rate is slower as enzymes cannot move.