aetiological agents linked to cancer

Question 1

describe how smoking can lead to mutations?

Answer 1

polycyclic aromatic hydrocarbons can form adducts with DNA guanine, leading to replication errors (the nucleotide with the massive adduct cannot be replicated properly)

Question 2

give 2 viral mutagens

Answer 2

HPV, Epstein Barr

,

Question 3

give 3 environmental mutagens

Answer 3

UV, asbestos, cigarette smoke

Question 4

What di dPercival Pott prove

Answer 4

a malignancy could be caused by an environmental carcinogen.

Question 5

what proportion of global deaths are caused by smoking

Answer 5

10%

Question 6

what do cytochrome p450 enzymes do and what has that got to do with smoking. which cells are affected?

Answer 6

polycyclic aromatic hydrocarbons in smoke are made into more soluble compounds by p450 for excretion.
However, the compounds produced(BDPE) are highly reactive and highly mutagenic, BDPE makes adducts with guanine. epithelial cells of the lungs

Question 7

which important gene is more commonly mutated in the lungs cancers of smokers than in other lung cancers

Answer 7

p53

Question 8

how does alcohol form mutagens

Answer 8

ADH enzyme transforms etoh into acetaldehyde. acetaldehyde is itself a weak mutagen and can form adducts with deoxyguanosine, but acetaldehyde can also interact with other amino acids to form a stronger adduct

Question 9

name 3 types of DNA damage that can be caused by mutagens

Answer 9

depurination, depyrimidation, DNA adducts

Question 10

what do pre-carcinogens need to form mutagens

Answer 10

metabolic activation

Question 11

what are ultimate carcinogens?

Answer 11

highly reactive species which directly bind to DNA

Question 12

how can viruses cause cancer?

Answer 12

by integrating genes (often oncogenes or TSG inhibitors) into the chromosomal DNA of an infected cel