3.8 Mutations and stem cells Flashcards
What is a mutation ?
A change in the DNA base sequence of a gene
What can a gene mutation result in ?
A different amino acid sequence in the primary structure that causes hydrogen and ionic bonds to form in different locations, which results in a different 3D shape
What is an addition mutation ?
One extra base is added to the sequence
What is the result of an addition mutation ?
Frameshift- alters the codons which can code for different amino acids
What is a deletion mutation ?
One base is deleted from the sequence
What is the result of a deletion mutation ?
Causes frameshift to the left
What is a substitution mutation ?
One of the bases is changed for a different base
What is an inversion mutation ?
When a section of bases detach from the DNA sequence, but when they rejoin they are inverted so this section of code is back to front
What is duplication ?
One particular base is duplicated at least once in the sequence
What effect does a duplication mutation have ?
Cases frameshift to the right and a different sequence of amino acids are coded for
What is translocation ?
A section of bases on one chromosome detaches and attaches onto a different chromosome
What are the impacts of translocation ?
Can cause significant impact to gene expression and therefore the resulting phenotype
What are stem cells ?
They are undifferentiated cells that can continually divide and become specialised
What is the name of the process by which stem cells become specialised ?
Differentiation
What is a totipotent stem cell ?
Can differentiate into any type of body cell
