11/13/2023 0 Comments Radium effects on body biologyBecause of this, alpha particle sources are usually not dangerous if outside the body, but are quite hazardous if ingested or inhaled (see the Chemistry in Everyday Life feature on Radon Exposure). A very thin barrier, such as a sheet or two of paper, or the top layer of skin cells, usually stops alpha particles. This is why patients undergoing radiation therapy often feel nauseous or sick to their stomach, lose hair, have bone aches, and so on, and why particular care must be taken when undergoing radiation therapy during pregnancy.ĭifferent types of radiation have differing abilities to pass through material ( Figure 21.33). Its effects are more pronounced in cells that reproduce rapidly, such as the stomach lining, hair follicles, bone marrow, and embryos. Radiation can harm either the whole body (somatic damage) or eggs and sperm (genetic damage). Biological Effects of Exposure to Radiation Examples of direct and indirect damage are shown in Figure 21.32.įigure 21.32 Ionizing radiation can (a) directly damage a biomolecule by ionizing it or breaking its bonds, or (b) create an H 2O + ion, which reacts with H 2O to form a hydroxyl radical, which in turn reacts with the biomolecule, causing damage indirectly. (This is true of any substance with unpaired electrons, known as a free radical.) This hydroxyl radical can react with all kinds of biological molecules (DNA, proteins, enzymes, and so on), causing damage to the molecules and disrupting physiological processes. The damage can also be done indirectly, by first ionizing H 2O (the most abundant molecule in living organisms), which forms a H 2O + ion that reacts with water, forming a hydronium ion and a hydroxyl radical:īecause the hydroxyl radical has an unpaired electron, it is highly reactive. Ionizing radiation, however, may cause much more severe damage by breaking bonds or removing electrons in biological molecules, disrupting their structure and function. Although biological systems are sensitive to heat (as we might know from touching a hot stove or spending a day at the beach in the sun), a large amount of nonionizing radiation is necessary before dangerous levels are reached. The damage this does to biomolecules in living organisms can cause serious malfunctions in normal cell processes, taxing the organism’s repair mechanisms and possibly causing illness or even death ( Figure 21.30).įigure 21.31 Lower frequency, lower-energy electromagnetic radiation is nonionizing, and higher frequency, higher-energy electromagnetic radiation is ionizing.Įnergy absorbed from nonionizing radiation speeds up the movement of atoms and molecules, which is equivalent to heating the sample. When these particles strike and penetrate matter, they produce ions and molecular fragments that are extremely reactive. For example, alpha and beta particles emitted from nuclear decay reactions possess much higher energies than ordinary chemical bond energies. The most serious biological damage results when these radioactive emissions fragment or ionize molecules. When this radiation encounters living cells, it can cause heating, break chemical bonds, or ionize molecules. All radioactive nuclides emit high-energy particles or electromagnetic waves. The increased use of radioisotopes has led to increased concerns over the effects of these materials on biological systems (such as humans).
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