changes due to 'the absorption of energy of these agents. differ significantly from the changes occurring in the energy absorption of ionizing radiation. When the energy absorption of ionizing radiation are excited molecules of the body, accompanied by energy migration along the giant organic molecules. This property determines the radiation iopieiruyuschey some features of its biological action. However, these processes occur at the molecular level and under the influence of other agents. The same can be said about the ability of ionizing radiation induce formation of reactive radicals, which exist in neobluchenpom body, but in much lower concentrations. It is widely believed that radiation has a very high ability to affect the body by a very small expenditure of energy. This argument is usually used dtgya evidence that ionizing radiation is exceptional stimulus, not comparable with any. any other. For example, Mayrer (1958) gives the following account: 'irradiated in a lethal dose 10 000 * p-ionieir uetsya in the body of 1 atom of 10 million, the body temperature rises by 0.020 C. This temperature change is not only not harmful, but in practice and is not noticeable. However, if you count the energy consumed with th not in 1 gram, as is usually done based on the definition of the unit dose, and throughout the body, then the result will be different. Followed up the calculations. In a man weighing 70 kg and 10 000 irradiated at a dose of P absorbed energy is about 7,000 joules. If this amount of electrical energy to bring to the body at once, the fatal effect is inevitable. Indeed, a deadly current of 1 ampere at a voltage of 7000 volts, which is equivalent to the energy release 7 kilojoules. Consequently, unsettled agents who, by their energy costs required to produce a specific biological effect, close enough to ioniziruyushey radiation. ' Rightly considered to be a threshold effect of ionizing radiation as well as any of its quantum, having an energy of at least 30 elec-tron-ox (eV), which can disrupt chemical bonds. However, it is not on the threshold of the reaction of the organism, but only the doorsteps of the biological stimulus. In other words, this property characterizes the feature of ionizing radiation, rather than the body's ability to respond to radiation exposure that • very important for the characteristics of an organism as reacting substrate. Based on the doorsteps of the concepts of radiation genetics ionnziruyuschey developed understanding of the probability of damage cells by inactivation of biologically important molecules in contact with her ionizing photon and p- * X-ray (p) - a unit of exposure dose of gamma-and X-rays. At a dose of 1 r in 1 ml of air at a temperature of 00 C and a pressure of 760 mm ps: ST. formed 2,1. 109 ion pairs.