Biology - Mutations and mutagens
Mutations and mutagens
Mutations can occur after exposure to environmental factors such as
A mutation early in development can cause people with the genotype for
blue eyes to develop one brown eye
A mutation is a change in the genetic material in a cell. If the sequence
of bases in the DNA of a cell is altered in some way then the production of
proteins in the cell is affected. There is some evidence that cells have
'self repairing' abilities to correct errors in DNA  replication.
Mutations can be random (spontaneous) or initiated by some environmental
factor (induced) such as UV radiation, X-rays or chemicals. A factor that
causes an increase in the frequency of mutations is a mutagen.
Some mutations  are harmful or even lethal. Many mutations have no
effect at all or the effect is harmless. Occasionally a mutation may be
beneficial to an organism in that it results in a variation in a
characteristic that increases its chances of survival. The effect of the
mutation is entirely dependent on the location and amount of the DNA
affected. It can be a point mutation or a whole or part chromosomal
Cancer cells dividing. Mutations which affect a cell's ability to
regulate growth and development can cause cancer.
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