Supplementary reading

meristem culture plant cells cultured from the undifferentiated meristematic tissue from which new cells arise.

mesophile an organism which has an optimum growth between 20*C and 40*C, including most human pathogens.

microscope an instrument for making very small objects appear larger, especially for scientific study.

muscle a piece of elastic body tissue that can be tightened or relaxed to produce movement.

mycelium composed of a mass of fungal hyphae tangled together.

natural selection the process by which heritable advantageous traits become more common in successive generations, and unfavourable traits become less common.

nutrient a substance that helps a living thing to grow.

order a group of related animals or plants below a class and above a family.

pathogen a microorganism or virus that causes disease.

phylum (plural phyla) a major group to which animals or plants belong.

plant a living thing that grows in the earth and usually has a stem, leaves and roots.

plasmid a small, usually circular molecule of DNA that occurs in bacteria but is not part of the bacterial chromosome. Plasmids have been used as cloning vectors to transfer genes between species.

prokaryotae a kingdom of microscopic, mainly unicellular microorganisms, including bacteria. Their DNA is circular, naked, and not situated inside a nuclear membrane. Prokaryotic cells also lack membrane-bound organelles, such as mitochondria.

protoctista a kingdom of microscopic, eukaryotic organisms. They may be unicellular or multicellular, and mainly show sexual reproduction. It is a diverse group including heterotrophic and photosynthetic organisms.

protoplasts plant cells that have had their rigid cellulose cell walls removed. They are fused to produce cell hybrids and used as targets for gene transfer in plant genetic engineering.

recombinant DNA DNA molecule that has been formed by joining together segments of DNA from two or more sources.

root the part of a plant that grows under the ground, absorbing water and minerals.

sample one of a number of things, one part of a whole, that can be examined in order to seewhat the rest is like; a specimen.

sap the liquid in a plant that carries food to all parts of it.

seed the part of a plant from which a new plantof the same kind can grow.

species a group of animals or plants within a Genus. Members of a species are able to breed with each other but usually not with other species.

stem the main long thin part of a plant above the ground, or any of the smaller parts growing from this, from which the leaves or flowers grow.

substrate a compound acted on by an enzyme and converted to a product.

vector in biotechnology, a vector is a DNA molecule which is used to transfer genes into cells; usually this is plasmid or viral DNA.

vegetation plants in general; plants found in a particular environment.

viable live; capable of reproducing.

virology the study of viruses and some other virus-like agents.

virus a particle containing a nucleic acid core, either DNA or RNA, surrounded by a protein coat called a capsid. Viruses are obligate parasites that reproduce by entering cells and taking over the cell`s own protein synthesizing mechanisms.

vital connected with or essential to life.