Chapter 22 - Cloning and Biotechnology

Question 1

How can we produce natural clones of plants?

Answer 1

Vegetative Propagation

- part of a plant is seperated, then develops into a new plant genetically identical to the original.

Question 2

How should a plant cutting be taken for cloning?

Answer 2

Cut stem between the leaf and the nodes.

Replant and allow to grow, sometimes using plant hormones.

Question 3

How can we produce artificial clones of plants?

Answer 3

• Tissue culture - place samples on various nutrient-containing mediums - encourage cell divison + shoot growth.
• Micropropagation - material produced from tissue culture is rapidly multiplied to produced large numbers of plants.

Question 4

Evaluate the use of artificial plant cloning in agriculture.

Answer 4

+ Large numbers of plants can be produced regardless of weather conditions
-reduces genetic variation, making 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 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. Cell develops into an embyro and can be implanted into a womb.
• Embryo splitting; same process by which twins form, performed artifically.

Question 7

Give arguments surrounding cloning in animals.

Answer 7

+ Quick process - suits quickly growing earth population.
+ 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 - benefits environment

Question 9

Give some ways microorganisms are used in biotechnological processes

Answer 9

• Food - baking, brewing
• 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 + purified
• Contains different amino acids to animal proteins.

Question 12

Describe the technique that should be used to culture microorganisms

Answer 12

Aseptic technique - keep everything sterile so that no unwanted microorganisms are present in the culture.

Question 13

Summarisre the three steps of growing microorganisms

Answer 13

1. Sterilisation; part of 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

• Temp maintained at optimum
• Sufficient nutrient supply
• Aerobic conditions to prevent products of anaerobic respiration
• pH kept constant - maximise enzyme activity

Question 16

Desribe the growth curve of a microorganism in a closed culture

Answer 16

Lag = cells increase in size + take in water - population constant.
Log = cells divide. Population increases expontentially
Stationary = nutrient levels decrease, slowing growth rate. Population stabilises
Death = toxic metabolites increase to a point that kills cells. Population declines.

Question 17

What is an immobilized enzyme?

Answer 17

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

Question 18

Give methods of immobilizing enzymes

Answer 18

1. Bonding - enzyme binds with support ionically or covalently
2. Entrapment - enzyme placed in semi-permeable membrane - cannot leave
3. Membrane seperation - partially permeable membrane seperates enzyme from substrate.

Question 19

Give uses of immobilized enzymes

Answer 19

• Glucose to fructose converstion
• Semi-synthetic penicillin production
• Lactose to Glucose conversion
• Pure amino acid samples
• Dextrins to Glucose conversion

Question 20

Evaluate the uses of immobilized enzymes.

Answer 20

+ Product is not contaminated by enzyme - no purification necessary
+ Enzymes can be reused
+ Enzymes protected from harsh environment
- Expensive
- Reaction rate is slower - enzymes can’t move.