Year 12 Gene Expression - mutations to phenotype and environment

Mutation

change in the base sequence of DNA to make new alleles.

Spontaneous mutation

Mutation caused by mistake happening in DNA REPLICATION.

Sometimes can be reversed (enzymes).

Generally get more as get older

Induced mutation

Mutation caused by MUTAGENS (virus, radiation, chemicals).

Can change genotype and then phenotype of living thing.

Insertion mutation

Insert bases(s) in DNA

Substitution mutation

Different base in DNA than original base

Deletion mutation

Remove base(s) from DNA

Same-sense mutation

Change of base doesn't change amino acid being coded for

Missense mutation

Change in base changes amino acid, but not over protein

nonsense mutation

Change in base completely changes DNA (stop codon) and protein

Frame-shift

Deletion or insertion bases changes reading of triplets. (usually lethal)

Enzyme

Biological catalysts, type of protein (speed up or slow down chemical reactions in living things)

Denatured

Change the shape of an enzyme so that it can no longer speed up a reaction.

Metabolic pathway

Series of enzyme controlled reactions where the reactants (substrate) become products and can then become reactants for the next reaction step.

Substrate

The reactant on which an enzyme works.

Phenotype

Characteristic (or feature) expressed

Genotype

An organism's genetic makeup, or allele combinations.

Allele

An alternative form of a gene.

Gene

A section of DNA that codes for a particular phenotype.