Substances that cause DNA mutations are known as mutagens, and mutagens that cause cancers are known as carcinogens. Particular substances have been linked to specific types of cancer. Tobacco smoking is associated with many forms of cancer, and causes 90% of lung cancer.
Human diploid cells have 46 chromosomes and human haploid gametes (egg and sperm) have 23 chromosomes. Retroviruses that contain two copies of their RNA genome in each viral particle are also said to be diploid.
Human Chromosomes Our chromosomes are found in the nucleus of each of our body cells. We have 46 of them, matched up into 23 pairs. Egg and sperm cells, however, have only 23 chromosomes; and when they come together to make a baby, he or she will get 46. The first 22 chromosome pairs (called âautosomesâ) are the same in men and women. The sex. chromosomes make up the 23rd pair.