IndexIntroductionDefinition and ExplanationMutagenChemical mutagenAlkylatorsPhysical mutagensCarcinogenConclusionIntroductionNowadays, there are various chemicals that are exposed to humans naturally or synthetically. It can be present in pharmaceuticals, cosmetics, pesticides and even foods. Few of the chemicals found in the typical everyday product may be carcinogenic chemicals that can be dangerous to humans over long periods of exposure. Cancer is characterized by the uncontrollable proliferation of cells and the spread of abnormal cells in the human body system. It can also cause death without proper treatment. Some chemicals can cause mutations and disrupt DNA replication in humans by providing or interrupting certain signals in humans. These types of chemicals are known to be toxic compounds. There are several types of toxic compounds that are teratogenic, mutagenic and carcinogenic. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an Original EssayDefinition and ExplanationMutagenMutagen is a physical or chemical agent that can cause permanent mutations to DNA and can also induce cancerous cells. According to the Occupational Safety and Health Act (2017), mutagen is also generally considered genotoxic because it can alter the structure, information or segregation of DNA. Mutagen can be divided into chemical and physical mutagen. Chemical mutagen Chemical mutagen can be defined as compounds that increase the rate of mutation. It works by interacting with DNA and causing changes in the DNA sequence. It occurs through the process of deletion, addition or replacement of DNA bases. When there is a mutation in the DNA sequence, protein synthesis will be prevented or produce a modified protein. As a result, it will cause diseases and give different signals to the organ and cells. An example of chemical mutagens are alkylating agents and azides. Base Analogues Base analogue mutagen is a chemical base capable of disturbing the replication system. mimics normal purine and pyrimidine bases. This will lead to incorrect insertion of nucleotides into replication. As a result, the base pairing and structure of DNA will change. Examples of mutagenic base analogs are 5-bromouracil because it can pair with both adenine and guanine. It shows that 5-bromouracil can mimic thymine and added to DNA by pairing with adenine or guanine. It is added into DNA due to tautomerization. For this reason, incorrect base pairing will eventually lead to mutation. In addition to this, mutagenic base analogs can also prevent DNA synthesis by inhibiting the production of certain enzymes. Alkylators Alkylators are chemicals that can change the structure and pairing properties of DNA. It can modify the structure by adding an alkyl group into the basic DNA structure. Examples of alkylating agents are ethyl methanesulfonate (EMS) and nitrosoguanidine (NG). According to Griffiths, Miller, Suzuki, Lewontin, and Gelbart (2000), ethyl methanesulfonate will add oxygen to the 6-position of guanine resulting in an O-6-alkylguanine. As a result it will pair poorly with thymine and produce different base pairings in replication, while inducing mutation. In addition to this, alkylating agents are also said to modify the bases of dNTPs. This can cause a disruption in DNA synthesis as they are the precursors to the process. Physical mutagens There are two types of physical mutagens: ionizing radiation and non-ionizing radiationionizing. Ionizing radiation is radiation with sufficient energy needed to remove bound electrons from an atom. This process will result in the formation of excited molecules that can cause damage to DNA and even cellular components when exposed to humans. Furthermore, ionizing radiation is capable of penetrating cells and causing mutations in human cells. Examples of ionizing radiation are X-rays, γ-rays, and α-particles. It is highlighted by Lerner and Lerner (2003) that X-rays and γ-rays have a high penetration compared to other radiations. Because of this, it will cause an even distribution of energy causing more serious damage. Meanwhile, an example of non-ionizing radiation is UV radiation. UV radiation can also affect DNA bases producing lethal lesions in DNA that are pyrimidine dimmers. This dimer will block the transcription and DNA replication process. Meanwhile, teratogens are substances that can cause birth defects by injuring or attacking the fetus during pregnancy. Teratogens may be closely related to embryotoxins which are poisonous to the developing fetus. The teratogenicity of an agent depends on the ability of the compounds to penetrate the placenta. Apart from this, it can also induce birth defects in newborns during the development of the fetus. The severity of the defects depends on the duration of exposure, the amount of substance, the concentration of the substance and also the embryonic stage of the fetus. The most famous case in the history of teratogenic compounds would be the use of thalidomide as a medicine against nausea and morning sickness. Over the years, there has been an increasing number of newborns with limb malformations called phocomelia. After extensive research, it was concluded that thalidomide is the main cause of phocomelia as it is a teratogenic agent. Phocomelia is the shortening of the limbs due to the reduced length of the proximal elements and the abandonment of only the distal elements. Thalidomide is a synthetic derivative of glutamic acid and the parent molecule of thalidomide is said to be the teratogenic compound in humans. Furthermore, metabolic conditions occurring in pregnant women are also considered as second category of teratogens. This is because abnormalities that occur in the chemical process of the pregnant woman will significantly affect the development of the fetus. According to Tantibanchachai (2014), diabetes can cause neural tube, brain, and spinal cord defects due to the presence of excessive blood sugar levels in a pregnant woman's system. This shows that teratogenic agents can also be the disease of a pregnant woman, as well as foreign compounds that people are ingested or exposed to. It is important for the pregnant woman to avoid contact with teratogenic substances. The first trimester of a woman's pregnancy is vital to the development of the fetus, so the mother should be especially cautious about what she eats and the chemicals she is exposed to. Teratogens include ethanol, mercury compounds, carbon disulfide, and toluene. Besides that, there are also common items that contain teratogenic compounds such as alcohol, cigarettes, and drugs. Apart from that, the pregnant woman must also ensure that she is in good condition and avoid any dangerous compounds. CarcinogenicCarcinogenic substances are commonly associated with causing cancer not only in humans but also in animals. The process that causes cancer is called carcinogenesis. Carcinogenesis is a process of cancer forming from normal cells. Carcinogens can occur naturally or synthetically. Carcinogens are also capable of accelerating cell division and preventing it automatically.