Cloning And Biotechnology

Question 1

Evaluate artificial plant cloning.

Answer 1

GOOD: new plants grow faster, desirable traits retained, naturally hard to grow some plants, free from viruses, uniform phenotypes
BAD: monoculture, susceptible to disease, expensive, labour intensive, lots lost if contaminated.

Question 2

Evaluate natural plant clones.

Answer 2

GOOD: prevent extinctions, many offspring in less time, advantage of favourable conditions.
BAD: less genetic diversity, less able to adapt, ethics, leads to overcrowding.

Question 3

Define vegetative propagation.

Answer 3

Asexual reproduction from vegetative parts of a plant rather than via specialised sexual reproductive structures.

Question 4

How can natural plant clones form?

Answer 4

Many plant cells remain totipotent. Tubers = underground stems that can form buds which grow shoots.
Horizontal stems can form roots of their own eg. Runners.

Question 5

How do elm trees reproduce asexually and why is this bad?

Answer 5

Using root suckers from meristem tissue. Root suckers form a circle = clonal patch.
Beetles are a vector for Dutch elm disease as fly between trees. Elm root suckers = clones without resistance and contaminate.

Humans helped spread by cutting down diseased trees and reusing the saws.

Question 6

What are methods of producing artificial plant clones?

Answer 6

1. Cuttings - stem cut between 2 leaf nodes and replanted in soil, rooting powder.
2. Micropropagation - samples of meristem = explants removed and sterilised with ethanol on culture medium. Stimulate mitosis to form many undifferentiated cells = callus.

Question 7

How are natural animal clones formed?

Answer 7

Identical twins by embryo splitting. Reproductive cloning - reproduce whole organism.

Question 8

What are the different types of artificial animal clones?

Answer 8

Non reproductive - for other purposes. Therapeutic cloning.
Reproductive - embryo transplants, somatic cell nuclear transfer.

Question 9

What is the method for embryo transplants?

Answer 9

Sperm and egg from selected parents, zygote from IVF divides many times to form an embryo. Implanted into surrogates.
Phenotype uncertain.

Question 10

What is the method for SCNT?

Answer 10

Unfertilised egg enucleated and adult body cell removed for cloning. Fixed with empty egg cell with electric shock - stimulate to divide. Embryo implanted into surrogate mother.

Question 11

Evaluate animal cloning.

Answer 11

• produce genetically identical - donation
• increase the number of endangered species
• offspring with desired traits
• high yields
• susceptible to disease
• very little variation
• destroy embryos - ethics
  Welfare concerns for animals produced.

Question 12

Define biotechnology.

Answer 12

Use of living organisms/parts of living organisms in industrial processes. Eg. Make food, drugs.

Question 13

What are uses of microorganisms in biotechnology?

Answer 13

Food: yeast to make ethanol and bread, mycoprotein, lactic acid in cheese.
Enzymes: protease in washing powder, lactase, sucrase to make sweetener.
Drugs: penicillin, antibiotics, insulin.
Other: biogas, citric acid, bioremediation.

Question 14

What is bioremediation and advantages?

Answer 14

Remove pollutants from soil or water.
Stimulate growth by ensuring have conditions necessary. If conditions not make in situ, polluted soil dug up and treated ex situ.
Advantages: not expose works to harmful chemicals, natural processes, faster as bacteria divide rapidly, lower labour costs.

Question 15

Evaluate the use of mycoproteins.

Answer 15

GOOD: faster than protein from animals, biomass with high protein and no cholesterol, no animal welfare issues, GM aa content, not affected by seasons.
BAD: protein extracted and purified, biomass has high nucleic acid content - remove, some aa missing, conditions favour pathogens.

Question 16

Why are microorganisms used in industry?

Answer 16

• cheap and easy to grow
• lower temps = cheaper
• can be fed waste products
• easy to GM
• bacteria have short life cycles
• often pure products

Question 17

Define aseptic techniques and why they are necessary.

Answer 17

Culturing microorganisms using sterile techniques to prevent contamination.
So not contaminated sample with pathogens and other bacteria.
- wash hands with soap, disinfect area, sterilise in autoclave.

Question 18

How is a microorganism cultured aspectically?

Answer 18

Work as close as possible to flame (hot air rises, microorganisms in air away). Inoculate using inoculating loop or glass pipette and sterile glass spreader.
Draw zigzag on agar plate to spread colonies evenly.
Reframe loop to remove the bacteria.
Tape plate in cross to maintain aerobic conditions.
25’C so not grow pathogens.
Store upside down.

Question 19

Define primary and secondary metabolites.

Answer 19

Primary - produced in normal growth/metabolism. In exponential phase. Harvest in continuous culture.
Secondary - not essential for normal metabolism - produced in stress. Harvest in batch culture. In stationary phase.

Question 20

What conditions are needed in a fermenter to manufacture mycoproteins?

Answer 20

Air ensures conditions are aerobic, air bubbles to mix.
NH3 = nitrogen source for aa.
Cooling removes excess heat from respiration - optimum temp
Glucose syrup from breakdown of plant starch by amylase and minerals for nutrition.

Question 21

Describe a growth curve in a closed culture.

Answer 21

Lag phase - cell switches on genes + synthesis of proteins and enzymes - acclimatise.
Log phase - bacteria divides by binary fission, high nutrient availability and space.
Stationary phase - less nutrients, high population density, division rate = death rate.
Death phase - nutrients used, death rate greater, toxic levels of waste products.

Question 22

How are serial dilutions useful when culturing microorganisms?

Answer 22

Used to decrease the concentration of a solution by a known amount.
1. Serial dilution
2. Grow colonies on agar plate
3. Count colonies
4. Multiply up to estimate population size

Question 23

When are logarithmic scales used?

Answer 23

When a large range of values plotted on a graph - easier to read each individual data point.

Question 24

Define immobilised enzyme.

Answer 24

Enzyme that is held in place and not free to diffuse through the solution.

Question 25

Describe and evaluate adsorption in immobilising enzymes.

Answer 25

Enzymes bound to supporting surface eg. Clay/glass beads with hydrophobic interactions and ionic bonds.
Bad: AS shape altered by increased interactions, slowing activity. Bonds not strong enough so enzymes leak into reaction mixture.
Good: cheaper

Question 26

Describe and evaluate covalent bonding and cross linking in immobilising enzymes.

Answer 26

Enzymes bonded to supporting surface with strong covalent bonds -> cross linking.
Bad: expensive, AS shape changed as tertiary structure affected.
Good: less likely to detach and leak into mixture.

Question 27

Describe and evaluate entrapment/membrane separation in immobilising enzymes.

Answer 27

Enzymes trapped into matrix or separated from mixture by partially permeable membrane.
Bad: substrate must be small enough to diffuse through matrix, less access limits rate.
Good: enzymes unaffected by entrapment - remain fully active.