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 it 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 so makes them more 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 twins

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 on 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, Yoghurt, Cheese
Medicine; penicillin, insulin
Environmental; removing polution

Question 10

Give advantages of using microorganisms to produce food for human consumption

Answer 10

+ Production rate easily varied
+ Not dependant 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

Aspetic 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

Question 16

Describe the 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 stabilises
Death = toxic metabolites increase to a point that kills cells. Population declines

Question 17

Give the formula for bacterial growth

Answer 17

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 18

What is an immobilised enzyme

Answer 18

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 19

Give methods of immobilising enzymes

Answer 19

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 20

Give uses of immobilised enzymes

Answer 20

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

Question 21

Evaluate the use of immobilised enzymes

Answer 21

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