Question

1. Which of these is not true about carcinogens:

	a.	all of these are true
	b.	They do not need to be ingested to cause cancer
	c.	They typically damage DNA
	d.	They are always artificial (or non-natural)

Answer 1

d.false.

They are always artificial is false

A carcinogen is any substance, radionuclide, or radiation that promotes carcinogenesis, the formation of cancer.

There are many natural carcinogens. Aflatoxin B₁, which is produced by the fungusAspergillus flavus growing on stored grains, nuts and peanut butter, is an example of a potent, naturally occurring microbial carcinogen. Certain viruses such as hepatitis B and human papilloma virus have been found to cause cancer in humans.

Option b and c are true about carcinogens.

They do not need to be ingested to cause cancer.

Eg.radiations like gamma and UV rays are not need to be ingested to cause cancer.

They typically damage DNA.

Carcinogens may increase the risk of cancer by altering cellular metabolism or damaging DNA directly in cells, which interferes with biological processes, and induces the uncontrolled, malignant division, ultimately leading to the formation of tumors. Usually, severe DNA damage leads to programmed cell death, but if the programmed cell death pathway is damaged, then the cell cannot prevent itself from becoming a cancer cell.