A2 OCR Biology Biotechnology and Gene Technologies

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A2 Biology Revision Notes Biotechnology and gene technologies
Clones in nature
Natural vegetative propagation
Asexual reproduction in plants takes place naturally in a variety of different ways. For example, a
number of plant species, including the English elm are adapted to reproduce asexually following
damage to the parent plant. This allows the species to survive catastrophes such as disease or
burning. New growth in the form of root suckers, or basal sprout, appears within 2 months of the
destruction of the main trunk, these suckers grow from meristem tissue in the trunk close to the
ground, where least damage is likely to have occurred.
Artificial clones and agriculture
Artificial vegetative propagation
The two main methods of artificial propagation for plants are;
Taking cuttings ­ a section of stem is cut between leaf joints. The cut end of the stem is then
often treated with plant hormones to encourage root growth, and planted.
Grafting ­ a shoot section of a woody plant is joined to an already growing root and stem
(called the rootstock).
Artificial propagation using tissue culture
Cuttings and graftings cannot produce huge numbers of cloned plants very easily. More modern
methods use plant tissue culture in order to generate huge numbers of genetically identical plants
Micropropagation by callus tissue culture
Small piece of tissue is taken from the plant to be clones, usually from the shoot tip. This is
called an explant
The explant is placed on a nutrient growth medium
Cells in the tissue divide, but they do not differentiate. Instead they form differentiated cells
called callus
After a few weeks, single callus cells can be removed from the mass and placed on a
growing medium containing plant hormones that encourage shoot growth
After a further few weeks, the growing shoots are transferred onto a different growing
medium containing different hormone concentrations that encourage root growth
The growing plants are then transferred to a greenhouse to be acclimatised and grown
further before they are planted outside
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A2 Biology Revision Notes Biotechnology and gene technologies
Advantages and disadvantages of plant cloning in agriculture
Advantages;
Farmers know what the crop plant produced will be like as it is coned from plants with known
features such as high yield, taste, colour and disease-resistance
Farmer's costs are reduced as all the crop is ready for harvest at the same time
Micropropagation is much faster than selective breeding, as huge numbers of genetically
identical plants can be generated from a small number of plants or a…read more

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A2 Biology Revision Notes Biotechnology and gene technologies
Advantages and disadvantages of cloning animals
Advantages Disadvantages
High-value animals (e.g. cows giving high milk High value animals aren't necessarily produces
yield) can be cloned in large numbers with animal welfare in mind.…read more

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A2 Biology Revision Notes Biotechnology and gene technologies
Biotechnology basics
Biotechnology ­ technology based on biology and involves the exploitation of living organisms or
biological process to improve; agriculture, animal husbandry, food science, medicine and industry
The use of microorganisms in biotechnology
Many biotechnological processes make use of microorganisms.…read more

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A2 Biology Revision Notes Biotechnology and gene technologies
Primary and secondary metabolites
Primary metabolites ­ substances produced by an organism as part of its normal growth.
They include;
Amino acids
Proteins
Enzymes
Nucleic acids
Ethanol
Lactate
Production of primary metabolites matches the growth in population of the organism
All microorganisms produce primary metabolites
Secondary metabolites ­ substances produced by an organism that are not part of its normal growth.…read more

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A2 Biology Revision Notes Biotechnology and gene technologies
Very useful for processes involving production of Very useful for processes involving production of primary
secondary metabolites metabolites
Importance of manipulating growing conditions
The precise growing conditions depend on the microorganism being cultures, and on whether the
process is designed to produce a primary or secondary metabolite.…read more

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A2 Biology Revision Notes Biotechnology and gene technologies
However, if the enzyme molecules are held so their active site is not changed and is
displayed, adsorption can give very high reaction rates
Covalent bonding
Enzyme molecules are covalently bonded to a
support, often by covalently linking enzymes
together and to an insoluble material (e.g.…read more

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A2 Biology Revision Notes Biotechnology and gene technologies
The sequencing reaction can only operate on a small length of DNA. This means that the genome must
be broken up and sequenced in sections. In order to ensure that the assembled code is accurate,
sequencing is carried out a number of times on overlapping fragments.
The stages involved are as follows;
Genomes are first mapped to identify
which part of the genome they have come
from.…read more

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A2 Biology Revision Notes Biotechnology and gene technologies
Electrophoresis is used to separate DNA fragments based on their size. It is widely used in gene
technology to separate DMA fragments for identification and analysis. The technique uses a gel plate
containing aragose (a sugar) which is covered in buffer solution. Electrodes are attached to each end
of the gel so that a current can be passed through it.…read more

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A2 Biology Revision Notes Biotechnology and gene technologies
Mixture is heated to 95°C. This breaks the hydrogen bonds holding the complementary
strands together, so making the samples single-stranded
Short lengths of single-stranded DNA are added. These are called primers
Temperature is reduced to around 55°C, allowing the primers to bind and form small sections
of double-stranded DNA at either end of the sample
DNA polymerase can bind to these double-stranded sections
Temperature is raised to 72°C.…read more

Comments

Swallowtail

A complete and detailed set of notes on biotechnology and gene technologies that contain lots of coloured images and flow diagrams to help illustrate the key points. Although written with the OCR A2 Biotechnology specification in mind, these notes would be useful for any student needing to study these topics.

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