OCR Biology A2 Unit 2 Module 2 Notes-Biotechnology and Gene Technologies

VEGETATIVE PROPAGATION: the production of structure in an organism that can grow into new individual organisms. These offspring are clones of the parent.

CLONE: genes, cells of whole organisms that carry identical genetic material because they are derived from the same original DNA.

Advantages of asexual reproduction: quick, completed if sexual reproduction fails or is not possible, all offspring have the genetic information to survive.

Disadvantage: no genetic variety.

Natural vegetative propagation in plants: takes place in a variety of different ways, adapted to reproduce asexually following damage to the parent plant-new growth, basal sprouts-grow from meristem tissue in trunk close to the ground, where least damage is likely to have occurred, root suckers help elm spread, suckers grow in a clonal patch, dutch elm disease-english elm responds to the destruction of the main trunk by growing root suckers, but then smaller ones die-they are clones so they have no resitance-no genetic variation.

Taking cuttings: a section of stem is cut between leaf joints (nodes), cut end treated with hormones to encourage root growth, and planted.

Grafting: a shoot section of a woody plant is joined to an already growing root and stem. The graft grows and is genetically identical to the parent plant, but the rootstock is genetically different.

TISSUE CULTURE: the separation of cells of any tissue type and their growth in or on a nutrient medium. In plants, callus tissue is grown in hormones.

Micropropagation: tissue taken from shoot tip (explant), placed on growth medium-cells divide-form undifferentiated cells called callus. After a few weeks, single callus cells can be removed and placed on a growing medium containing plant hormones that encourage shoot growth, after a few weeks, on a different medium containing different hormone concentrations that encourage root growth, growing plants transferred to a greenhouse, then outside.

Disadvantages: reduced variation, all plants equally susceptible to disease.

Advantages: fives desired characteristics, know what you're getting, reduced costs, quick.

CLONE: been produced using the same genetic information as another animal, has the same genotype as the donor organism.

Splitting embryos: cells from a developing embryo can be separated out, with each one then going on to produce a separate, genetically identical organism.

Nuclear transfer: a differentiated cell from an adult can be taken, and its nucleus placed in an egg cell which has had its own nucleus removed (enucleated). Egg then goes through the stages of development using genetic information from the inserted nucleus.

Advantages: high value, rare animals, GM animals can be cloned.

Disadvantages: no animal welfare considerations, clones unable to adapt to change, it is still unclear whether animals cloned using nuclear transfer will remain healthy in the long term.

Non-reproductive cloning: advantages: no rejection, no waiting for donor, can be used generate any new cell type, less dnagerous. Possibilities: new heart muscle, new nervous tissue, repair spinal chord-therapeutic cloning. Induced pluripotent stem cells (iPS cells).

BIOTECHNOLOGY: technology based on biology and involves the exploitation of living organisms or biological processes, to improve agriculture, animal husbandry, food…