human genome Flashcards
Describe different ways of DNA damage
- Base loss
- Base modification
- Single-stranded breaks
- Double strand breaks
How does ionising radiation cause DNA damage
double stranded breaks
How to repair double stranded breaks
- Homology-dependent repair
* Non-homologous end-joining
Describe homology dependent repair
• information is copied from the sister chromatid
or homologous chromosome
• no information is lost
describe non-homologous end-joining
non-conservative
DNA sequences are lost from the cell
when does apoptosis occur
when DNA damage is irreparable
Which one requires a lot of energy
homology dependent repair
The enzyme that adds complimentary bases to a growing DNA strand is a?
polymerase
Sometimes, when a cell acquires a lot of DNA damage, it will undergo a process called apoptosis, also known as programmed cell death. Why?
Because the risk of not repairing the damage is too great
What is the condition where covalent bonds are formed between adjacent thymine bases due to damage from UV light.
Thymidine dimerisation
Which enzyme follows DNA polymerase to check for mistakes during DNA replication?
DNA mismatch repair complex
What is the condition due to defect in homology dependent repair?
Nijmegen breakage syndrome
What is the condition due to mutation in DNA mismatch repair genes
Hereditary non-polyposis colon cancer
What is the condition caused by double-stranded breaks in chromosomes, resulting in translocation of the chromosomes.
Chronic myelogenous leukaemia
