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Recombinant DNA technology

changing the DNA of an organism by using vectors to add foreign DNA to the cells

Mutagenesis

taking wild strains of micro-organisms and causing mutations with radiation or chemicals

Microorganisms

organisms too small to be seen without magnification

Migration

the avoidance of metabolic diversity by expending energy to relocate to a more suitable environment

Aestivation

a dormancy response caused by very dry or hot conditions

Hibernation

a way of surviving low temperatures by building up fat stores before entering a state of dramatically reduced metabolic rate

Daily torpor

a period of reduced activity in some animals with small body size and high metabolic rates

Glycolysis

the breakdown of glucose to pyruvate in the cytoplasm

Enzyme inhibitor

a substance which slows down or stops the activity of an enzyme

Activation energy

the energy needed to allow a reaction to occur

Membrane pump

a protein that actively takes certain substances across the membrane by changing shape

Protein pore

a channel through a membrane that allows substances to pass in and out

Catabolic reactions

ones which break down large molecules into smaller molecules and release energy

Anabolic reactions

ones which build up large molecules from small molecules and require energy

Metabolic pathways

chains of integrated and controlled enzyme-catalysed reactions within a cell

Translation (in ribosome)

the formation of a polypeptide from the code carried by mRNA

Transcription (in nucleus)

transfer of the genetic code from DNA to mRNA

Primers

short sequence of single stranded DNA

Genetic code

the specific sequence of bases

Personalised medicine

using genome information to determine the exact drug and dosage for an individual

Pharmacogenetics

using the genome information to choose the most effective drugs for an individual

Molecular clocks

measure of the mutations that occur over time, used to work out when speciation occurred

Phylogenetics

using genomic sequencing to work out evolutionary relationships between different species

Genomic sequencing

when the sequence of nucleotide bases is determined for individual genes or for the entire genome

Species

a group of organisms capable of breeding to produce fertile offspring and which does not normally breed with other groups

Speciation

the generation of new biological species by evolution as a result of isolation, mutation and selection

Stabilising selection

when the average phenotype is most successful in a given habitat. frequency of extreme phenotypes is reduced

Disruptive selection

when the average phenotype is least successful in a given habitat, frequency of extreme phenotype is increased

Directional selection

when one extreme phenotype is more successful in a given habitat, frequency of the other extreme will decrease

Natural selection

the non-random increase in frequency of DNA sequences that increase survival and the non-random reduction in the frequency of deleterious sequences

Evolution

changes in organisms over generations as a result of genomic variations

Gene duplication

when a mutation causes a second copy of a gene to be made, which becomes altered and provide new DNA sequences, important for evolution

Splice site mutation

the codons that control exon-intron splicing are changed - altered mature mRNA is formed

Nonsense mutation

an amino acid coding codon is replaced by a premature stop codon, the protein translation stops too early so the correct protein is not formed

Missense mutation

one amino acid is replaced by another

Single gene mutation

the alteration of a DNA nucleotide sequence

Mutations

changes in DNA that can result in no protein or an altered protein being synthesised

Genome

the entire hereditary information coded on DNA

Multipotent cells

stem cells in a tissue, they can differentiate into any cell type of that tissue

Pluripotent cells

cell in a very early embryo, can differentiate into any of the cell types found in the individual

Meristems

regions of unspecialised cells in plants that can divide or differentiate

Stem cells

undifferentiated cells that are capable of cell division

Gene expression

when the DNA code of a gene is used to produce a protein

Codons

sets of three bases on mRNA that carry the genetic code

Anticodons

three exposed bases on tRNA

Cellular differentiation

When a cell becomes specialised by expressing certain genes that make characteristic proteins