6.2.1 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 seeds, so naturally self propagates using roots.

Question 2

How should a plant cutting be taken for cloning ?

Answer 2

Stem is cut between leaf and nodes, replanted and allowed to grow with the aid 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 formed 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

Pros : Large number of plants can be produced regardless of season
Cons : Reduces genetic variation of diversity, making susceptible to disease.

Question 5

Give an example of natural cloning in animals

Answer 5

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

Question 6

How can we produce genetic clones of mammals ?

Answer 6

Somatic cell nuclear transfer and embryo splitting

Question 7

Explain the process of somatic cell nuclear transfer

Answer 7

•When a diploid somatic (body) cell has its nucleus transferred to an enucleated egg, and they are fused via electricity
•The cell develops into an embryo and can be implanted in the womb of a surrogate.

Question 8

What is the process of embryo splitting ?

Answer 8

The same process by which twins form, can be performed artificially.

Question 9

Give pros and cons of cloning animals

Answer 9

Pros - Quick process, can protect endangered species
Cons - Cloned animals may suffer defects, low genetic diversity.

Question 10

Why are microorganisms suited for use in biotechnological processes ?

Answer 10

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

Question 11

Give some ways microorganisms are used in biotechnological processes

Answer 11

*Food: baking, brewing, yoghurt, cheese
*Medicine; penicillin, insulin
*Environmental; removing pollution (bioremediation).

Question 12

Give advantages of using microorganism to produce food for human consumption

Answer 12

*Production rate easily varied
*Not dependant on climate
*Long-lasting
*Uses waste products.

Question 13

Give disadvantages for using microorganisms to produce food for human consumption

Answer 13

*Lack flavour
*Proteins must be isolated and purified
*Contain different amino acid to animal proteins.

Question 14

Describe a technique that should be used to culture microorganisms

Answer 14

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

Question 15

Summarise the three steps of growing microorganisms

Answer 15

1. Sterilisation, part of the aseptic technique
2. Inoculation, microorganisms introduced to agar plate
3. Incubation, the plate is then placed in a warm environment for 24-48 hours to grow.

Question 16

Differentiate between batch and continuous fermentation

Answer 16

*Batch - closed environment, competition for resources, maintains culture in stationary phase, easy to setup, less efficient
*Continuous - Products continually removed, maintains culture in the log phase, harder to setup, more efficient.

Question 17

How are the growth conditions of fermentation manipulated to maximise yield ?

Answer 17

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

Question 18

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

Answer 18

*Lag - cells increase in size and take in water, population is 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 19

Give the formula for bacterial growth

Answer 19

N= No x 2ⁿ
-> N = number of bacteria currently in population
->No = number of bacteria before division
*ⁿ= number of divisions.

Question 20

What is an immobilised enzyme

Answer 20

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

Question 21

Give 3 methods of immobilising enzymes

Answer 21

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 and substrate.

Question 22

Give uses of immobilised enzymes

Answer 22

*Glucose to fructose conversion
*Semi-synthetic penicillin production
*Lactose to glucose/galactose conversion
*Pure sample of amino acids
*Dextrin to glucose conversions.

Question 23

What are the pros and cons of immobilised enzymes ?

Answer 23

Pros -
*Product is not contaminated by enzyme so does not need to be purified
*Enzymes can be reused
*Enzymes are protected from harsh environment

Cons -
*Expensive
*Reaction rate is slower as enzymes cannot move.