8.1-2 Gene Expression Flashcards
What are the 6 types of mutation?
Substitution Addition Deletion Inversion Duplication Translocation
What are the substitution mutations?
Silent - the same amino acid is coded for
Mis-sense - a different amino acid is coded for
Non-sense - a stop codon is coded for
What does addition and deletion mutations result in?
A frame shift
All subsequent codons are altered and therefore every amino acid after that - it can have devastating effects
What is an inversion mutation?
A group of bases is separated and rejoins at the same position but in the reverse order
What is a duplication mutation?
One or more bases are repeated which can result in a frame shift
What is a translocation mutation?
A group of bases is separated in one chromosome and inserted in the base sequence of another chromosome
= significant effects in the phenotype
What causes mutations?
Ionising radiation
Chemical mutagens
Spontaneous errors
How can mutations benefit organisms?
It produces genetic diversity which is necessary for natural selection
What are stem cells?
Undifferentiated cells which can keeping dividing to give rise to other cells
What are the types of stem cells? Order of ability to differentiate
Order of ability to differentiate: Totipotent Pluripotent Multipotent Unipotent
What are totipotent and pluripotent stem cells?
Totipotent - They can form any type of cell as they only translate part of their DNA
Including embryonic stem cells
Pluripotent - they can form any type of cell in the body but not embryonic
They are found in the early stages of an embryo
What are multipotent and unipotent stem cells?
Multipotent - can differentiate into other cell types but are more limited eg bone marrow and umbilical cord
Unipotent - they can only differentiate into one type of cell
How are embryonic stem cells produced?
The inner mass of a blastocyst is removed and isolated once the trophoblast (outer layer of cells) is destroyed using lasers
The embryonic stem cells are cultivated and they can add different growth factors to trigger
What can be produced from unipotent cells?
Induced pluripotent cells (iPS)
By using the appropriate protein transcription factors
What can affect gene transcription?
Oestrogen
siRNA