核酸的结构与功能-核酸的化学组成 核酸的结构与功能 The Structure and Function of Nucleic Acic 1868年,瑞士的内科医生 Friedrich Miescher从外科医院包扎伤口的绷带上的脓 细胞核中提取到一种富含磷元素的酸性化合物,将其称为核质(nuclein);后来 他又从鲭鱼精子中分离出类似的物质,并指出它是由一种碱性蛋白质与一种酸 性物质组成的,此酸性物质即是现在所知的核酸(nucleic acid)1944年 Oswalo Avery, Colin Macleod和 Maclyn McCarty发现,一种有夹膜

Changes in the Nature of Work The Interweaving of Technology and Jobs Changes in the Design of Jobs (there will be no stable jobs in the future Integration of Contingent Workers into the Workforce Increased Emphasis on Continuous Learning External Control of Performance Standards by Customers (Boom of services industry) Limitations on Leadership and Supervision Changes in the Structure of Work From Individuals to Teams

经济类课件汇集_Module07 CAPITAL STRUCTURE

Two kinds of data structure Linear: list, stack, queue, string Non-linear: tree, graph

1. General studies of the peptide bond 1.1 The peptide(O=C-N-H) bond was found to be shorter than the C-N bond in a simple amine and atoms attached are coplanar. 1.1.1 This was revealed by X-ray diffraction studies of amino acids and of simple dipeptides and tripeptides. 1.1.2 The peptide (amide) bond was found to be about 1.32 A (C-N single bond, 1.49; C= double bond, 1.27), thus having partial double bond feature (should be rigid and unable to rotate freely)

Chemists use spectroscopy (Ir, UV-Vis, NMR) to determine molecular structure. spectroscopy: technique that measures the amount of radiation a substance absorbs at various wavelengths(based on the quantization of molecular energy levels Molecules exist in quantized energy states (rotational, vibrational, and electronic quantum states) Molecules absorb discrete amounts of energy(ae)and are excited to higher

Unit Two Teaching aims: 1. to learn the new words and expressions; 2. to improve reading skills 3. to analyze the structure of the text II.Teaching focus: 1.key words:

I Teaching aims: 1. to learn the new words and expressions; 2. to improve reading skills 3. to analyze the structure of the text II.Teaching focus: 1.key words:

I Teaching aims: 1. to learn the new words and expressions; 2. to improve reading skills 3. to analyze the structure of the text II.Teaching focus: 1.key words:

I. Vocabulary and structure 1. On my way to school, I saw people _advertisements and sample products. A. conveying B.creating C. discarding D. distributing 2. The professor thought that I was making good progress in my studies and told me to my good work A. keep up B. go ahead with C. hold back D. come up with