Physical and chemical mutagens. What is the difference between a physical mutagen and a 2022-10-30
Physical and chemical mutagens Rating:
Physical mutagens are agents that cause mutations, or changes in the genetic material, in an organism through physical means. These can include ionizing radiation, such as X-rays and gamma rays, as well as UV light and certain chemicals.
Ionizing radiation can cause mutations by directly damaging the DNA molecule, either through the formation of free radicals or by breaking the sugar-phosphate backbone of the DNA helix. These types of mutations can be particularly harmful, as they can affect multiple genes at once and may lead to cancer or other genetic disorders.
UV light is a type of non-ionizing radiation that can also cause mutations, although these are typically less severe than those caused by ionizing radiation. UV light can cause changes in the DNA molecule through the formation of pyrimidine dimers, which are bonds between adjacent pyrimidine bases on the same strand of DNA. These bonds can disrupt the normal structure of the DNA helix and interfere with the process of DNA replication, leading to mutations.
Certain chemicals can also act as physical mutagens, either through their ability to damage DNA directly or through their ability to interact with and alter the structure of the DNA molecule. These chemicals can include certain drugs and environmental toxins, such as tobacco smoke and air pollution.
Chemical mutagens, on the other hand, are agents that cause mutations through chemical means. These can include certain types of chemical compounds, such as alkylating agents and base analogs, which can react with and modify the DNA molecule.
Alkylating agents are chemicals that can add alkyl groups to the DNA molecule, disrupting its normal structure and function. These agents can be particularly harmful, as they can cause cross-linking between the DNA strands, which can interfere with DNA replication and lead to genetic mutations.
Base analogs are chemical compounds that can mimic the structure of normal DNA bases, such as adenine, cytosine, guanine, and thymine. When these analogs are incorporated into the DNA molecule, they can interfere with the normal process of DNA replication and lead to genetic mutations.
Overall, physical and chemical mutagens are agents that can cause mutations in the genetic material of an organism, which can have a variety of harmful effects on the organism's health and development. It is important to be aware of the potential risks posed by these agents and to take steps to minimize exposure to them.
What are Chemical Mutagens? Definition and Types
A very common and widely used base analogue is 5-bromouracil 5-BU which is an analogue of thymine. Due to such pairing properties 5-BU is used in chemotherapy of viruses and cancer. They are densely ionizing, but lesser penetrating than beta rays and neutrons. Ultraviolet UV Radiation : UV radiation causes damage in the DNA duplex of the bacteria and phages. Is nitrous oxide a mutagen? Such mutations are induced by chemical mutagens or radiations which are present in the external environment to which an organism is exposed. Inter-strand dimers cross link nucleic acid chains, inhibiting strand separation and distribution.
What is Physical Mutagenesis? Definition, Causes & Physical Mutagens
Cells use different DNA-repair mechanisms to undo the changes that occurred in the DNA strand like excision repair, photoreactivation repair, mismatch repair and many more. All these three genes are recessive lethal. The seeds are treated with a mutagen. In a live cell radiation damage to proteins, lipoproteins, DNA, carbohydrates, etc. In Mutagenicity: Assays and Applications.
The mutant form of apolipoprotein possesses antioxidant characteristics in addition to removing cholesterol and dissolving plaques and has aided the Italian population from cardiac diseases. Insertion of the correct base does not alter the normal DNA sequence. The example of mutator gene is dotted gene in maize. They are sparsely ionizing but more penetrating than alpha rays. They are made of two protons and two neutrons and thus have double positive charge.
Physical and chemical mutagens improved Sporotrichum thermophile, strain ST20 for enhanced Phytase activity
Ultraviolet Rays : UV rays are non-ionizing radiations, which are produced from mercury vapour lamps or tubes. Temperature also affects the frequency of spontaneous mutations. Common mutagens include: bromine, sodium azide, psoralen, benzene, x-rays, gamma rays, alpha particles, ultraviolet radiation, etc. The survival curve of bacteria is given in Fig. Insertion of incorrect bases results in transversion or transition mutation.
For example, spontaneous rearrangements of DNA bases result in base pair transitions. Non-ionizing radiations result in DNA excitation due to photon UVA and UVB absorption by the cells. Of these, cobalt 60 is commonly used for the production of Gamma rays. Besides high yield, varieties have been developed with better quality, earliness, dwarfness, disease resistance and low toxin contents in various crops. This produces 50% progeny as curly lobe and 50% as plum. Induced mutations have been used for increasing the range of genetic variability in barley, oats, wheat and many other crops.
In this context, we will discuss the definition and different types of chemical mutagenic agents like base analogues, base altering agents and intercalating agents. X-rays, valproate, and toxoplasma are standard physical, chemical, and biological teratogens, respectively. The 5-BU functions like thymine and pairs with adenine Fig. They cause alternations in base pairing and DNA structure, affecting DNA replication and gene expression. What are some physical and chemical agents that cause mutations? Among the females, half have CIB chromosome and half normal chromosome Fig. Effects : Mutations are generally harmful to the organism.
What is the difference between physical mutagens and chemical mutagens?
Therefore, we can say that the radiations cause damage at a molecular level, as they affect the DNA biomolecule directly ionization or excitation or indirectly through the formation of highly reactive free radicals. This oil is a component of Lemongrass Tea in central and southern India. The change or shift of hydrogen atoms from one position to another either in a purine or in a pyrimidine base is known as tautomeric shift and such process is known as tautomerization. Chapter Ten — Mutagenicity Testing: Regulatory Guidelines and Current Needs. The 2-amino-purine 2-AP and 2, 6-di-amino-purine 2, 6-DAP are the purine analogues. Who find out the physical mutagen in Drosophila? The rare enol form of 5-BU that pairs with G is the first mutagenic step of replication. What are mutagens name a chemical mutagen? The I is a recessive lethal.
What is the difference between a physical mutagen and a
Xanthine pairs with cytosine. ADVERTISEMENTS: In this article we will discuss about the chemical and physical types of mutagens. Since the effect of alkylating agents resembles those of ionizing radiations, they are also known as radiomimetic chemicals. Direction of Change : ADVERTISEMENTS: Mutations usually occur from dominant to recessive allele or wild type to mutant allele. Those which are used as mutagens are nitrous oxide HNO 2 , hydroxylamine HA and ethyl-methane-sulphonate EMS. Heat stress, heat shock or hyperthermia are the terms used for the term heat, which can cause lethal effects on the DNA integrity and termed as heat-stress induced DNA damage.
Tobacco smoke produces mutagenic urine, and it is a human somatic-cell mutagen, producing HPRT mutations, SCEs, microsatellite instability, and DNA damage in a variety of tissues. They may occur in any gene nuclear or cytoplasmic , in any cell somatic or reproductive and at any stage of development of an individual. What is mutagen describe physical mutagen? Spontaneous Mutations : Naturally occurring mutations are known as spontaneous mutations. The F 1 progeny of such cross is grown and a search is made to detect plants with recessive phenotype for a specific gene. Normal Apolipoprotein is the protein responsible for the transportation of cholesterol.
Hence, the ratio of thymine-thymine TT , thymine-cytosine TC , cytosine-cytosine CC dimer Fig. Nickel, chromium, cobalt, cadmium, arsenic, chromium, and iron are a number of the standard metal ions that cause mutations. Example: Chlorophyllin and some dietary fibers. What are mutational hotspots? They are generated from radioactive decay of some elements like 14C, 60C, radium etc. UV rays, X-rays, alpha rays, neutrons, and other ionising and non-ionizing radiations are mutagenic. A wide variety of agents are categorized as carcinogens. These are briefly described below: i.