Mutation Flashcards
What is germ line mutation?
mutation in gametes - that will pass on to offspring
What is Somatic mutation?
Changes in body cells - might lead to cancer
What are the possible affects of mutation?
- No effect
- Malfunction/Loss of function/Gain of function
- Disease/Disorders
- Lethal
What are the causes of mutation
- Errors in DNA replication
- Errors in cell cycle
- Errors in DNA repair mechanism
- Exposure to radiation, heavy metals and chemicals
- Organisms - Bacteria, pathogens and others
- Non-living thing - virus
Types of mutations
- Point mutation
- Silent
- Missense
- Nonsense
- Transistion
- Transversion - Frameshift mutation
- Deletion
- Insertion - Exon skipping
What is silent mutation?
silent mutation is a point mutation, no change in amino acid in the protein sequence.
What is missense mutation?
missense mutation is a point mutation. A base substitution result in an amino acid change.
What is nonsense mutation?
nonsense mutation is a point mutation. Base substitution results in coding of a stop codon. which causes premature termination of the protein.
What is frame shift mutation?
Frame shift mutation is due to insertion or deletion of one or more nucleotides. It causes an alteration of the reading frame.
What is exon skipping?
If the splice accpetor site AG is mutated, the splicing machinery will look for the next acceptor site. As a result, the exon between two introns is also removed.
What chemicals alter DNA structure?
Psoralens - found in some vegetables and used in treatments of some skin conditions cause intra- and inter-strand cross links)
Peroxides - chemicals causing DNA strand breaks
What are the types of radiation that causes DNA mutation.
X ray, gamma and cosmic rays - are energetic enough that they produce reactive ions (charged atoms or molecules) that can break the DNA duplex.
Radioactive elements
UV radiation - reacts with DNA and make thymine dimer (T-T)
