Environmental Effects On Phenotype Flashcards
Environmental Effects
Environmental factor - an internal or external factor that affects the organism’s phenotype but does not affect the organism’s genotype.
Mutagen - a physical or chemical factor that causes/increases the chance of changes to the base sequence of DNA, and therefore, the genotype of an organism.
Phenotype and Environment
Phenotype - the set of observable characteristics of an individual resulting from the interaction of its genotype with the environment.
Phenotype = genotype + environment
Mutations impact the phenotype because they cause a change in the genotype which results in a change to the protein. The environment can also impact the phenotype of the individual without changing the genotype (e.g. enzyme denaturing).
The offspring do not inherit the phenotype, as the genotype hasn’t changed. The organism’s phenotype may also change if the environment changes. Interactions with the environment stop the gene from being expressed, without altering the gene itself.
Environmental Effects on Metabolic Pathways
The enzymes in a pathway can become denatured or deactivated if exposed to environmental conditions outside the optimum, e.g. high/low temperatures, pH values. This can change the outcome of the metabolic pathway even though the gene is normal/non-mutated and is producing a fully functional enzyme during protein synthesis. It is the environmental condition which is denaturing the enzyme even though it was originally produced with the correct active site. This means that if the environment were to change, the enzyme could return to normal function because the body is constantly producing more proteins, and the genetic instructions are unchanged.
