Biotechnology and Gene Technologies

Question 1

Define Vegetative Propogation

Answer 1

The production of structures in an organism that can grow into new individual organisms. These offspring contain the exact genetic information as the parent and so are clones of the parent.

Question 2

What are clones?

Answer 2

Clones are two or more individuals which have the exact same genetic information as each other.

Question 3

What are the advantages of asexual reproduction?

Answer 3

Allows fast reproduction to take advantage of the resources around them.
Can be completed if sexual reproduciton fails.
All offspring will have the same genetic information so will be able to survive in the environment as it stands.

Question 4

What the disadvantages of asexual reproduction?

Answer 4

There is no genetic variation in the offspring so any weaknesses in the parents will also be in the offspring. This means that any changes to the environment will be equally dangerous to all individuals in that population.

Question 5

How do elm trees reproduce asexually?

Answer 5

Root suckers/basal sprouts form near the base of the tree if the trunk takes damage (such as disease or burning) aproximately 2 months after the damage. They form from the meristem tissue in the trunk close to the ground.

Question 6

What is the main advantage of basal sprouts for elm trees?

Answer 6

It allows the elm trees to spread over an area forming ‘clonal patches’ every time one of the trees dies, moving further and further out each time, so long as the resources permit it.

Question 7

What is the main disadvantage of basal sprouts for elm trees?

Answer 7

They are susceptible to dutch elm disease, just as much as their parents, which is likely the cause of death from the past 100 years. Once they get about 10 cm in diameter, they die in turn, causing more susceptible sprouts to grown and die.

Question 8

Define ‘Tissue Culture’

Answer 8

The separation of cells of any tissue type ad their growth in or on a nutrient medium. In plants, the undifferentiated callus tissue is grown in nutrient medium containing plant hormones that stimulate development of the complete plant.

Question 9

What are the two main methods of artificial vegitative propogation?

Answer 9

Taking cuttings and grafting

Question 10

Describe artificial vegitative propogation by taking cuttings

Answer 10

A section of the stem is cut between leaf joints (nodes), treated with plant hormones and planted. This produces a clone of the plant the cutting was taken from.

Question 11

Describe artifical vegitative propogation by grafting

Answer 11

A shoot section of a woody plant is joined to an already growing root and stem (a rootstock). This graft grows and is a clone of the parent plant, but the rootstock is genetically different to the graft.

Question 12

Describe artificial vegetative propogation by tissue culture (micropropogation)

Answer 12

Small peice of tissue is taken from the plant to be cloned (from the shoot tip) and paced on a nutrient growth medium. These divide but do not differentiate, forming a callus. After a few weeks single callus cells can be taken and placed in a growth medium to grow, and then are taken and put in a different growth medium after shoots have started to grow. These plants are then put in a greenhouse to grow normally.

Question 13

Define a cloned animal

Answer 13

One that has been produced using the same genetic infomation as another animal. Such an animal has the same genotype as the donor organism

Question 14

What are the two methods of artificially cloning an animal?

Answer 14

Splitting embryos (ie. artificial identical twins)
Nuclear Transfer

Question 15

Describe how splitting embryos is able to produce a clone

Answer 15

Cells from an embryo can be sepaqreted to produce two cell masses rather than one, with each cell mass eventually developing into a genetically identical copy of the other.

Question 16

Describe how nuclear transfer is able to produce a clone

Answer 16

An egg cell is taken and the nucleus is removed (enucleated). This can be from any similar species to the individual being cloned. The nucleus is removed from a cell in the animal being cloned and put inside the egg cell. This now has the full genetic make up of the animal being cloned and can start developing into an embryo.

Question 17

What are the advantages of cloning?

Answer 17

High value animals (eg in farming) can be cloned in a large scale.
Endangered animals can be cloned in order to preserve a species.
Genetically modified animals are able to be produced on a large scale quickly, knowing that the genes needed are still there.

Question 18

What are the disadvantages of cloning?

Answer 18

High value, farming animals, are often produced with animal welfare not in mind (eg, chickens that cannot walk).
Excessive genetic uniformity means that the animal is unlikely to be able to adapt to changes in the environment very fast, if at all.
It is unclear the animals will remain healthy in the long term (Dolly died at age 6 suffering from lung cancer from a virus however the post mortem showed nothing out of the ordinary for her age).

Question 19

What is non-reproductive cloning?

Answer 19

Using cloned cells from the body to produce identical copies of organs and tissues to replace those that have been damaged through disease or accidents.

Question 20

What are the advantages of using cloned cells to produce organs for tranplants?

Answer 20

It will not be rejected as it is genetically identical to the old/damaged organ.
Could mean an end of waiting for donors to come forward.
Cloned cells can be used to generate any cell type as they are totipotent.
Less dangerous than some major operations such as a heart transplant.

Question 21

Define Biotechnology

Answer 21

Technology based on biology and involves the exploitation of living organisms or biological processes, to improve agriculture, animal husbandry, food science, medicine and industry.

Question 22

Why are microorganisms used so widely in various processes?

Answer 22

Grow rapily in favourable conditions
Produce chemicals or proteins that can be harvested
Can be genetically engineered to produce specific products
Grow well at relatively low temperatures
Can be grown anywhere in the world
Tend to produce purer products than processes they are not present in
Can be grown using nutrient materials that would otherwise we wasted

Question 23

Define A Culture

Answer 23

A growth of microorganisms. This may be a single species (which would be called a pure culture) or a mixture of species (called a mixed culture). Microorganisms can be cultured in a liquid such as nutrient broth, or on a solid surface as nutrient agar gel.

Question 24

Explain the lag phase of a standard growth curve

Answer 24

Organisms are adjusting to the surrouding conditions. This may mean taking in water, cell expansion, activating specific genes and synthesising specific enzymes. The cells are active but reproducing so population remains fairly constant. The length of this period depends on the growing conditions.

Question 25

Explain the stationary phase of a standard growth curve

Answer 25

Nutrient levels decrease and waste products like carbon dioxide and other metabolites build up. Individual organisms die at the same rate at which new individuals are being produced. In an open system, this would be the carrying capacity of the environment.

Question 26

Explain the Log (exponential) phase of a standard growth curve

Answer 26

The population size doubles each generation as every individual has enough space and nutrients to reproduce. In some bacteria, the population can double every 20-30 minutes in these conditions. The length of this phase depends on how quickly the organisms reproduce and take up the available nutrient and space.

Question 27

Explain the death/decline phase of a standard growth curve

Answer 27

Nutrient exhaustion and increased levels of toxic waste products and metabolites lead to the death rate increasing about the reproduction rate. Eventually, all organisms will die in a closed system.

Question 28

What does the term fermentation refer to?

Answer 28

The culturing of microorganisms both aerobically and anaerobically in fermentation tanks.

Question 29

Define Primary Metabolites

Answer 29

Substances produced by an organism as part of its normal growth; they include amino acids, proteins, enzymes, nucleic acids, ethanol and lactate. The production of primary metabolites matches the growth in population of the organism.

Question 30

Define Secondary Metabolites

Answer 30

Substances produced by an organism that are not part of its normal growth. The antibiotic chemicals produced by a number of microorganisms are almost all secondary metabolites. The production of secondary metabolites usually begins after the main growth period of the organisms and so does not match the growth in population of the organism.

Question 31

Define Aseptic Technique

Answer 31

Refers to any measure taken at any point in a biotechnological process to ensure that unwanted microorganisms do not contaminate the culture that is being grown or the products that are being extracted.

Question 32

Define Asepsis

Answer 32

The absence of unwanted microorganisms

Question 33

What are the growing conditions that need to be monitored during fermentation?

Answer 33

Temperature
Type and time of addition of nutrient
Oxygen concentration
pH

Question 34

What is Batch Culture

Answer 34

Where the mircroorganism starter population is mixed with a specific quantity of nutrient solution, then allowed to grow for a fixed period with no further nutrient added. At the end of the period, the products are removed and the fermentation tank is emptied. Penicillin is produced using batch culter of pinicllium fungus.

Question 35

What is Continuous Culture

Answer 35

Where nutrients are added to the fermentation tank an d products removed from the fermentation tank at regular intervals - or even, as the name suggests, continuously. Human hormones such as insulin are produced from continuous culture of genetically modified Escherichia Coli Bacteria.

Question 36

What are the advantages of Batch Culture?

Answer 36

It is easy to set up and maintain
Contamination means only one batch worth is lost.
Very useful for the production of secondary metabolites.

Question 37

What are the advantages of Continuous Culture?

Answer 37

Growth rate is very high as it is maintained at the log phase of growth.
More efficient as the fermenter operated continuously at a fast rate
Very sueful for producing primary metabolites.

Question 38

What are the disadvantages of a contaminated culture?

Answer 38

Microoganisms compete with each other for nutrient
Yield of useful products is reduced
May cause spoilage of the product
Toxic chemicals may be produced
Culture organisms and products may be destroyed

Question 39

Define Immobilisation of Enzymes

Answer 39

Refers to any technique where enzyme molecules are held and separated from the reation mixture. Substrate molecules can bind to the ezymes molecules, and the products formed go back into the mixture leaving the enzyme molecles in place.

Question 40

What are the advantages of immobilised enzymes?

Answer 40

Enzymes are not present with products so purification costs are low
Enzymes are immediately available for reuse
Enzymes are more stable because of the immobilising matrix so they can do their job just as well in a variety of conditions

Question 41

What are the disadvantages of immobilised enzymes?

Answer 41

Requires addition time and money to set up.
Enzymes can be less active as they do not mix freely
Any contamination is costly as the whole system would need to be stopped.

Question 42

What are the methods of immobilising enzymes?

Answer 42

Adsoption
Covelant Bonding
Entrapment
Membrane Separation

Question 43

Describe immobilising by adsorption

Answer 43

Enzymes are mixed with an immobilising support and bind to it through hydrophobic and ionic links. Adsorbing agents include porous carbon, glass beads, clays and resins. The bonds are not very strong so some enzymes can leak however as long as their active site doesn’t change shape it will not affect the efficiency.

Question 44

Describe immobilising by covelant bonds

Answer 44

Enzyme molecules covelantly bond to a support, often by linking them together and to an insoluable material (such as clay). A cross linking agent is used, such as gluteraldehyde or sepharose. This does not immobilise very many but stops almost all leakage.

Question 45

Describe immobilising by entrapment

Answer 45

Enzymes are trapped in a gel bead or a network of fibres. Enzymes are trapped in their natural state so the active site is not affected, however rates can be slowed due to the substrates have to get through the trapping barrier.

Question 46

Describe immobilising by membrane separation

Answer 46

Enzymes may be physically separated from the substrate mixture by a partially permeable membrane. The enzymes are held on one side and the subtrate is passed through from the other side. The products are small enough to pass back through the membrane.

Question 47

Define Genomics

Answer 47

Refers to the study of the whole set of genetic information in the form of DNA base sequences that occur in the cells of organisms of a particular species. The sequenced genomes or organisms are palces on public databases.

Question 48

Define Electrophoresis

Answer 48

Similar to Chromatography. Separation of the different leangths of DNA fragments, in a micture, is acheived because, as the negatively charged fargments move towards he positive electrode, shorter fragments pass through the gel more easily and so move further in a fixed time.