Mutation Flashcards
What is a mutation?
It is a sudden or spontaneous change in volume structure or arrangement of the DNA within a cell of an organism.
Where is it common for mutations to occur?
It is common in somatic (body) cells during the application before mitosis.
What would happen if the mutation occurred during meiosis?
The mutation would be inherited in the gamete formation of the offspring.
Do organisms with shorter cycles have higher or lower rates of mutation?
Higher
What are mutagens?
These are chemicals or radiation which increase the rate of mutation in the DNA of cells.
Name examples of mutagens?
Ionising radiation e.g. gamma radiation, UV light and x-rays, chemicals e.g. polycyclic hydrocarbons and carcinogens
What happens during gene mutation?
Nucleotides may be added or made from the DNA template strand which are undergoing semiconservative replication. This occurs during interphase before mitosis or meiosis.
What is gene mutation: substitution?
Is that when one base in the sequence is swapped with a different base.
What is the silent mutation?
It is when a change in base may still form a triplet code which codes for the same amino acid as the genetic code is generate.
What is a neutral mutation?
It is when the amino acid that is altered is not essential to the tertiary and Quaternary structure of the protein. Resulting in functionally different protein, so different allele forms.
What is gene point mutation: deletion and addition?
It is a type of mutation which causes a frameshift mutation (which is more severe). The addition or removal of a nucleotide in the DNA sequence changes the triplet of bases as well as the subsequent ones. This results in the mRNA carrying different codons with a polypeptide made up of completely new amino acids.
What is the result likely to be with deletion and addition?
A non-functional polypeptide and protein as a bonding within the tertiary structure is affected which means the shape of the protein has changed. Any mutation which results in the stop codon will have a similar result.
What is gene mutation: inversion?
It is when the gene mutation occurs in the junk DNA which exists between the genes. As this DNA does not code for polypeptide/proteins the mutations found within this area won’t influence the phenotype. This variation assists with genetic fingerprinting.
What are the substances called which cause cancer?
Carcinogens
What do carcinogens do?
They affect the DNA within cells which results in mutations. Most mutated cells are recognises foreign invaders by the immune system and are destroyed.
