Topic 20: Regulation of gene expression Flashcards
(21 cards)
What is degenerate code in genetics?
Some amino acids have more than one code word coding for them
What is a codon?
A triplet of three consecutive nucleotides that code for one amino acid
What does substitution refer to in a nucleotide sequence?
A nucleotide in a sequence has been substituted with another
What is deletion in the context of nucleotide sequences?
A nucleotide in a sequence has been removed from the sequence
What can be the three consequences of base substitution
- The new codon now codes for a stop codon
- The new codon now codes for a different amino acid
- The new codon now codes for the same amino acid (because the genetic code is degenerate)
What type of mutation causes frame shift
Base deletion / insertion
What are the 6 types of base mutations
- insertion / addition
- deletion
- inversion
- translocation
- substitution
- duplication
What is base inversion
when a short DNA sequence becomes separated from the full sequence then re-join at the same place but is back-to-front
What is translocation
a group of bases becomes detached from one chromosome and inserted into another chromosome
What do you call things that increase the chance of mutations
Mutagens / carcinogens
What are the two stages where you can stop genes being expressed
- Stopping translation
- Stopping transcription
Why can stem cells differentiate into different types of cells
Becuse no gene regulation in place
Which cells are 1-3 days old and can specialise into any type of body cell/extraembryonic cells or placenta cells
Totipotent
Which cells are 4-14 days old and can specialise into every type of body cell, but not the cells of the placenta or umbilical cord
Pluripotent
Which cells are adult stem cells that can differentiate into a few types of closely related cells
Multipotent
Which cells are adult stem cells that can only become one type of cell
Unipotent
State the types of stem cells from highest ability to differentiate to lowest
- Totipotent
- Pluripotent
- Multipotent
- Unipotent
How can you get pluripotent stem cells from adults and not embryos
Induced Pluripotent stem cells (iPSCs)
Where does a transcription factor bind to
Promoter region
Explain how transcription factors allow for transcription
- transcription factor binds to promoter region
- this forms a transcription initiation complex
- this allows RNA polymerase to attach and allows for transcription
