Mutations Flashcards
What is a genetic mutation?
Anything that changes the original DNA sequences in some way
Are all mutations major?
No. Most are subtle , and most people have some amount of mutations
What are the ways mutations can be brought on?
Either externally or internally
Define mutagen
Something that is capable of causing a mutation
External mutagens
Mutation caused by external influences
Examples: chemicals ingested in foods, cigarettes, gamma rays, UV rays, extreme heat. Can also be caused by simply being near something (ie somewhere like Chernobyl)
Internal mutagens
When a mistake occurs in the genetic process, internal cause
Chromosomal mutation
A mutation that effects the entire chromosome, can affect several genes. Usually occurs when the chromosome is crossing over
Substitution mutations
When one nucleotide base is replaced for another
Missence mutations
When a substitution mutation occurs and causes an amino acid different then intended
Nonsense mutation
When a mutation occurs and creates a premature stop/start codon
What is a stop codon?
When the nucleotides are being read 3 at a time, there are stop codons to tell when to stop translating (ends the protein)
Neutral mutation
Have no impact at all
For example: CCA and CCG code for the same amino acid, so if they are switched there will be no effect
What is a frame shift mutation
Causes the “stream” of nucleotides to be shifted in the ways it’s read. Caused by either an insertion (inserting an extra nucleotide) or a deletion (removing a nucleotide)
Causes amino acid to be affected
Benefits of mutations
Genetic diversity, can give an organism an advantage or disadvantage. Allows evolution
