Lecture 7 Flashcards
1
Q
Mutations
A
- Permanent change in DNA of a cell
- Change in gene position/number
- Change in nucleotide structure
- Mutations are rare but important (disease, variation)
- Occur randomly, usually detrimental
2
Q
Somatic cell mutations
A
- Not passed on to offspring
- Passed onto cells descended from original mutants
- 85% cancers caused
3
Q
Germ-line/Gamete tissues mutations
A
- Passed onto offspring
- Cause of genetic diseases
4
Q
Sickle cell anaemia
A
- Caused by single nucleotide substituation in haemoglobin
- From Glutamic acid -> valine
- Creates a sickle shaped haemoglobin
5
Q
Causes of mutation
A
- Spontaneous
- Physical mutagens
- Chemical mutagens
6
Q
DNA instabilites
A
- Can be caused by spontaneous mutations
- An incorrect base insertion can led to mismatched pairs
- Nucelotides can change to other conformatives (e.g., isomers)
7
Q
Induced mutations
A
Occurs when an outside agent (mutagen) damages DNA
8
Q
Chemical mutagens
A
- Resemble DNA base pairs but pair incorrectly
- That remove the amino group from edeniine or cytosine
- Chemicals that add hydrocarbon groups to nucelotide bases
9
Q
Intercalating agents
A
Inset between bases and distort DNA structure/ replication
10
Q
Physical
A
- Ionising radiation, damaging bases and cause double strand strand breaks
- Ultra-violet radiation, blocks DNA synethesis
11
Q
Cancer
A
- Caused by mutations in oncogenes or tumour suppressors
- Mainly in somatic cells (not inherited)
- 15% cause of cancer is inherited
