6.2.1~Cloning and Biotechnology

Define natural clones?

• Genetically identical copies

State the benefits and drawbacks of natural clones?

Benefits

• population can increase rapidly

• reproduction can be carried out with one parent

Drawbacks

• offspring may become overcrowded

• no genetic diversity(unless mutations)

• whole population susceptible to changes in the environment

Drawbacks

Define vegetative propagation?

• the production of plant clones from non reproductive tissues e.g. roots, leaves, stems

1. why is it important to produce very thin slices of plant tissue?

2. why is it important that the sections of a plant are cut truly transverse or longitudinal and not at an angle?

3. why are stains useful in microscopy?

4. why is toluidine blue useful for staining plants?

1. clearer if 1 cell thick, reduced quality of image if its thicker

2. it could distort the image

3. increase the contrast of cells so they can be seen more visibly

4. it is a differential stain, allows us to differentiate different cells

Define clone?

• a genetic copy of another single organism

define tissue culture?

• growing new tissues, organs or plants from certain tissues cut from sample plants

define micropropagation?

• when tissue culture is used to produce lots of cloned plants very quickly

state the process of micropropogation?

1. cells taken from shoot(explants) and sterilised

2. explants placed on sterile plant growth medium, stimulates mitosis to form a callus→production of lots of undifferentiated cells

3. The explant is placed on a sterile agar medium containing nutrients (glucose, amino acids, phosphates) and high concentrations of auxins and cytokinins, plantlets grow stimulates mitosis to form a callus→production of lots of undifferentiated cells

4. callus is divided

5. plantlets then transferred to compost

Evaluate the uses of plant cloning?

Advantages

• produces lots of plants quickly compared to time it would take to grow them from seeds

• desirable genetic characteristics are always passed on to clones, unlike when plants reproduce sexually

Disadvantages

• high production costs of tissue culture due to high energy use

• skilled workers needed

• no genetic variability, whole population can be killed by a single disease

Explain how identical twins are an example of natural clones?

• a fertilised egg(zygote) splits into 2

Explain the stages of artificial embryo twinning?

1. a fertilised egg (zygote) is created using IVF(in vitro fertilisation)

2. the zygote divides by mitosis to form a ball of cells

3. cells are separated and allowed to continue dividing

4. each mass of cells is placed into the uterus of a surrogate mother

define somatic cell?

• any cell which isn’t reproductive

Explain the stages of somatic cell nuclear transfer cloning?

• a somatic cell is taken from sheep A, the nucleus is removed from an unfertilised egg cell

• the nucleus is inserted into the egg cell of sheep B

• an electric shock stimulates the egg to divide by mitosis to form an embryo

• the embryo is inserted into the uterus of a surrogate sheep to continue development

Evaluate artificial cloning in animals?

FOR

• desirable genetic characteristics always passed on

• infertile animals can be reproduced

• increase population of endangered species

AGAINST

• time consuming

• expensive

• undesirable characteristics always passed on

define biotechnology?

• the industrial use of living organisms to produce food, drugs or other products

which organisms are commonly used in biotechnology?

• micro-organisms

state and explain 2 examples of biotechnology?

BREWING:

• used to make beer

• the yeast respires anaerobically using the glucose from the grain and produces ethanol and CO2

INSULIN PRODUCTION:

• hormone crucial for treating people with type 1 diabetes

• made from genetically modified bacteria which have gene for human insulin production

• inserted into their DNA

• bacteria grown in fermenter on massive scale

• insulin produced is collected and purified

explain reasons why micro-organisms are commonly used in biotechnology?

• their ideal growth conditions can be easily created

• can be grown on a range of inexpensive materials,so economical

• because of their short life cycle, they grow rapidly under the right conditions, so products can be made quickly

evaluate using microorganisms to make food for human consumption?

ADVANTAGES

• low production costs as micro-organisms have simple growth requirements, less land required in comparison to crops or rearing livestock

• micro-organisms can be cultured anywhere, food source could be readily produced in places where growing crops and rearing livestock is difficult

DISADVANTAGES

• people may not like the idea of eating food which has been grown using waste products

• conditions needed to grow the desired micro-organism are also ideal for other micro-organisms, extensive effort must be put in to ensure that the food doesn’t get contaminated