mutation Flashcards
3.34
what are mutations?
rare genetic changes
when do these changes occur?
randomly when the DNA is copied to make new chromosomes before cell division
what are the genetic changes in mutations caused by?
altercations to the DNA base sequence
what happens when mutations occur in the DNA of gametes?
they will be passed onto the next generation- mutations can be inherited
how can mutations sometimes lead to a change in the protein that the gene codes for?
the DNA base sequence determines the sequence of amino acids that make up a protein- mutations in a gene can sometimes lead to a change in the protein that the gene codes for
what can result from mutations?
new forms of genes
what is a mutation?
a change in the sequence of bases in DNA
how can mutations occur?
the replacement of a single base pair with a different pair, or an addition or deletion of one or more base pairs- gives a change in the DNA sequence- changes the sequence of amino acids in the protein- alters the shape and function of the protein
what are chromosomal mutations?
when a cell gains an extra chromosome- such as in Down’s syndrome
why are chromosomal mutations harmful?
they result in over or underproduction of proteins
what will happen if the mutation occurs during meiosis in gamete formation?
it will affect all of the cells in the individual which develops from the gamete- the mutation will be inherited
what happens if the mutation occurs in a body cell?
it will affect only those cells produced by mitosis from the affected cell
give rise to cancers of the cells that are affected
this type of mutation is not inherited
what are mutagens?
chemicals which cause more frequent mutations
what do mutagens include?
ionising radiations (gamma rays, x-rays and ultraviolet light)
some chemicals e.g. in tobacco
what do mutations increase?
genetic variation in a population
