Control of gene expeession Flashcards
Define gene mutation
Spontaneous changes in the sequence of nucleotides in DNA molecules
What are insertion/deletion mutations?
One or more nucleotide is inserted or deleted from the sequence and can cause a frame shift
What is a duplication mutation?
One or more bases is repeated and therefore produces a frame shift
What is an inversion mutation?
Group of bases become separated form the DNA sequence then rejoin at the same position in reverse order.
What is a translocation mutation?
Group of bases become separated from the DNA sequence on one chromosome and are inserted into the DNA sequence on another chromosome
What are the 3 types of substitutions and explain them?
Silent- does not alter the amino acid sequence
Missense - alters a single amino acid in the polypeptide
Nonsense- creates a premature stop codon
What are the effects of a mutation?
- Change amino acid
- Change in primary structure
- Change in tertiary structure
How do mutations arise?
-Spontaneously during DNA replication
- Mutagenic agents
What are the mutagenic agents?
- Chemical mutagens: like alcohol, tobacco
- Ionising radiation: alpha and beta, UV
- Spontaneous errors in replication
What are stem cells?
Undifferentiated cells which can keep dividing by mitosis to differentiate into different cell types
What is a totipotent stem cell?
Can differentiate into any stem cell
What is a pluripotent stem cell?
Can differentiate to most cell types
What is a multipotent stem cell?
Can differentiate to some cell types
What is a unipotent stem cell?
Can differentiate to one type of stem cell
What is a cardiomyocyte?
Muscle cell that makes up the heart and is responsible for contraction (unipotent)
What are embryonic stem cells?
Derived form totipotent cells and pluripotent cells
What are Adult stem cells?
Derived from multipotent cells
What are iPS cells?
Induced pluripotent stem cells, pluripotent cells that are created by unipotent cells, via protein transcription factors
How do cells differentiate?
Differences in how cells are expressed, so results in the synthesis of different polypeptide, determines the type of cell
What is stem cell therapy?
When pluripotent cells are stimulated to multiply and differentiate, these can be transplanted
