Lecture 7

Question 1

Mutations

Answer 1

• 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

Question 2

Somatic cell mutations

Answer 2

• Not passed on to offspring
• Passed onto cells descended from original mutants
• 85% cancers caused

Question 3

Germ-line/Gamete tissues mutations

Answer 3

• Passed onto offspring
• Cause of genetic diseases

Question 4

Sickle cell anaemia

Answer 4

• Caused by single nucleotide substituation in haemoglobin
• From Glutamic acid -> valine
• Creates a sickle shaped haemoglobin

Question 5

Causes of mutation

Answer 5

• Spontaneous
• Physical mutagens
• Chemical mutagens

Question 6

DNA instabilites

Answer 6

• Can be caused by spontaneous mutations
• An incorrect base insertion can led to mismatched pairs
• Nucelotides can change to other conformatives (e.g., isomers)

Question 7

Induced mutations

Answer 7

Occurs when an outside agent (mutagen) damages DNA

Question 8

Chemical mutagens

Answer 8

• Resemble DNA base pairs but pair incorrectly
• That remove the amino group from edeniine or cytosine
• Chemicals that add hydrocarbon groups to nucelotide bases

Question 9

Intercalating agents

Answer 9

Inset between bases and distort DNA structure/ replication

Question 10

Physical

Answer 10

• Ionising radiation, damaging bases and cause double strand strand breaks
• Ultra-violet radiation, blocks DNA synethesis

Question 11

Cancer

Answer 11

• Caused by mutations in oncogenes or tumour suppressors
• Mainly in somatic cells (not inherited)
• 15% cause of cancer is inherited