X-ray diffraction and molecular biology _3369

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X-ray diffraction and molecular biology

White matter has also made a major breakthrough. British female chemist in 1948, Hodgkin (D.M.C.Hodgkln1919 ~) and her colleagues are living index B of the first x-ray diffraction photographs, measured the vitamin Cable B: structure; 1951 British physicist Kendrew (J.C.Kendrew.1917 ~) x-ray diffraction analysis applications myoglobin, clarified the three-dimensional structure of myoglobin; 1968, the British physicist Perutz (M. Perutz1919 ~), with x-ray diffraction studies of protein structure, after 30 years of research and clarify the structure of hemoglobin. DNA double helix model of the 20th century's most important biological discovery of the concentration found in addition to Watson,[link widoczny dla zalogowanych], U.S. biochemist (J.D.Watson.1928 ~) and the British physicist SCIENCE Creek (F. Crick, 1916 ~) The ingenuity addition, x-ray diffraction is an important guide Programme. Coincidence is. The two scholars, doctoral thesis, and x-ray are related. Watson's doctoral thesis on phage replication in terms of x-ray effect. Creek's doctoral thesis on peptide and protein x-ray studies. It is this that they come together like-minded. The two scholars determined to make the structure of DNA is the structure of biological macromolecules 1951, the Italian Conference of the British physicist Wilkins (M. H. F. Wilkins, 1916 ~) on the DNA diffraction analysis. Wilkins and his colleagues won the first well-DNA fiber diffraction image and maintain the necessary conditions for crystallization of DNA fibers, in his view of the DNA molecules are elongated longitudinally of the trend. So easy to become a fiber; his DNA molecules to determine the shape of a spiral coil and that manufacturers have to meet the DNA helix DNA model for the diameter and the distance that end, Watson, Crick and Wilkins shared the 1962 Nobel Prize in Physiology and Medicine Award. Thus,[link widoczny dla zalogowanych], X-ray diffraction technique is the golden key to open the door to molecular biology. Experimental tests of air pollution - Environmental series of activities Pengkai Liang (Canton High School 525 200 First City) acid rain, air pollution levels can reflect the measured pH value of rainwater, you can determine whether the affected local air pollution to different degrees of hazard students can successfully and independently to complete the experiment can be divided into several sessions. A clear purpose of the experiment through the experiment, to enable students to master the method of determination of acid rain, environmental awareness, training to analyze and solve practical problems. 2 to impart basic knowledge (1) the causes of people in the production of acid rain, life on coal, oil and other fuel burning, is not on the correct handling of garbage (such as burning), will be containing a large amount of N, Ji S oxides (such as NO,[link widoczny dla zalogowanych], SO). These oxides are adsorbed airborne dust in the air. Further oxidation of NO. , SOs, and the formation of acid mist in the air. When it rains. They just like the reaction of acid rain falling to the ground. The consequences would permanent body and soil acidification, crop production or to curse income. To fish death. (2) the standard when the rain acid rain pH value of less than 56, this water belongs to acid rain. (3) pH value of rain water pH test strips precision measurement method is to measure the pH value of rain the easiest way. PH test paper to release the measured precision of the rain. Out immediately. Within the 5s with the color than the color chart compared to determine its corresponding pH value. 3, method step guide (1) sampling the rain, each group of students, respectively,[link widoczny dla zalogowanych], eliminating the organization to the local 3 different locations. Beaker with clean water 300ml44 a direct Sheng (2) measurements to retrieve the rain samples with pH test strips precision test their pH values; (3) record the results and concluded that the 3 groups of samples, the average pH value of rainwater as the times The pH value of the index. Continuous determination of the local 3 attack when it rains the rain pH. Every time the rain is acid rain on the conclusions. The date recorded in the following table to guide the average pH value of the conclusions of the results of 4 consecutive 3 rounds according to the local pH value of rain recorded, and guide students to analyze the degree of local air pollution, in particular, to guide students around the acid rain caused by environmental factors and external environmental factors for the overall , real analysis, investigation and research, write 5 questions survey measures in the investigation of the causes of acid rain, based on the requirements put forward students of acid rain control measures, such as anti-pollution plant species, transformation of production processes. Change the structure of fuel and fuel stoves. Strengthening vehicle inspection. Additional gas recovery and so on. An increase in the activities of students knowledge and improve the thinking and the ability to solve practical problems heard. Strengthened the sense of environmental awareness and community participation Biology Bulletin 33 of 1998 No. 1