Gene Expression Flashcards
Define gene mutation
Change to one or more of the nucleotide bases in DNA. These might arise during DNA replication
Name the six types of gene mutation
Substitution/ Deletion / Addition/ Duplication /inversion/ translocation
What does substitution case?
What are the three possible effects?
When nucleotides are replaced by another with a different base
Forms a stop codon
Forms codon for different aa
Form same aa due to degenerative code
Gene mutations can occur________
Gene mutations can occur spontaneously
Name two types of mutagenic agents
High ionisation radiation energy
Chemicals
What is a zygote?
Fertilized egg
Name 4 places were stem cells are found
Embryo
Umbilical cord blood
Placental
Adult - bone marrow
Name the four types of stem cells
totipotent
pluripotent
multipotent
unipotent
Where are totipotent and pluripotent found?
Embryo
Where are multipotent stem cells found?
What is their limitation?
Found in the adults
Can specialise into specific number of cells
How many types of cells can a unipotent stem cell turn into ?
one
What are iPS?
How are they produced?
Induced pluripotent stem cells
Produced from unipotent stem cells using appropriate protein transcription factor
Name the DNA-Histone complex
-Chromatin
Define acetylation
When acetyl group is transferred to a molecule
Describe what occurs when deacetylation occurs
makes histones more positive
so increases attraction to phosphate
so association of complex is stronger so transcription factors are less accessible
more difficult to switch on genes
Define methylation
Addition of CH3 group to a molecule
Describe was occurs when increased methylation happens
Prevents binding of transcriptional factor to DNA
Attact proteins that condense the complex
so gene switched off
Explain how the methylation of tumour suppressor genes can lead to cancer.
Methylation prevents transcription of gene;
Protein not produced that prevents cell division/
causes cell death/apoptosis;
No control of mitosis;
Suggest how transcription factors can reprogramme cells to form iPS cells
attach 2 gene + stimulate RNA polymerase
Describe how alterations to tumour suppressor genes can lead to the development of
tumours.
(Increased) methylation (of tumour suppressor
genes);
Mutation (in tumour suppressor genes);
Tumour suppressor genes are not
transcribed/expressed
OR
Amino acid sequence/primary structure altered;
Results in) rapid/uncontrollable cell division;
