Unit 1: Human Cells - Key Area 4 - Mutations Flashcards
What is a mutation?
Mutations are changes in the DNA, either in a gene or a chromosome, that can result in no protein at all or an altered protein being synthesised. this change in DNA can result in genetic disorders.
Are mutations rare and random?
Yes
What are mutations the only source of?
Mutations are the only source of new variation in populations.
What can mutations be for an organism?
Sometimes a mutation can be useful but many mutations have a harmful and lethal effect on an organism,
What is a mutant?
An organism which has been effected by and is the result of a mutation.
What are the two main types of mutation?
Gene and chromosome mutations.
What do single gene mutations involve?
A single gene mutation involves a change in the number or sequence of bases in a gene.
or
Single gene mutations involve the alteration of a DNA nucleotide sequence as a result of the substitution, insertion or deletion of nucleotides.
What are the three types of gene mutation?
Substitution, Insertion and Deletion.
What are substitution mutations?
Substitution mutations are point mutations and involve ONE base being exchanged for another. THEY WILL ONLY EFFECT ONE CODON.
What are insertion and deletion mutations?
Insertion and deletion are frame-shift mutations and effect every single codon after the mutation. This involves whole sections of DNA being misread.
What results in frame-shift mutations?
Nucleotide Insertion and Deletion.
What are the 3 types of substitution mutation?
Missense, Nonsense and Splice-Site.
What are the 2 frame-shift mutations?
Insertion and Deletion.
What is the description of a Missense mutation?
A type of substitution mutation which changes the codon for an amino acid so that a different amino acid is inserted into the protein.
What is the effect on the protein from a Missense mutation?
Different amino acid is inserted into the protein meaning a different protein is produced.
What is an example of a condition caused by a Missense mutation?
Sickle cell anaemia.
What is the description of a Nonsense mutation?
A mutation which results in a codon for a specific amino acid being changed to a stop codon.
What is the effect on the protein from a Nonsense mutation?
It causes the protein to be stopped prematurely and a shorter protein being produced.