生物化学课件：生化引论

1、,Biochemistry I,Wonderful world：Garden of Eden,Diversity and Unity,Amazing?!,Definition of Biochemistry,Biochemistry is the chemistry of life. The study of the molecular basis of life and the interact with each other or understanding life phenomena in chemical terms. The combination of biology and c

2、hemistry or the application of chemical principles to understand biology.,The Chemical Unity of Diverse Lives,Living organisms vs. inanimate objects chemical complexity and organization use energy in a systemic way self-replication and self-assembly Biochemistry Explains: Diverse lives in unifying c

3、hemical terms All macromolecules are made of a few simple compounds,Music in our body!,Main Questions for Biochemistry I (this semester):,What are the composition and structure of bio-molecules? How do these bio-molecules act and interact in living organisms？,All chemical process associated with org

4、anisms at the molecular level - isolate molecules and determine their structure - analyze their function Example: the study of DNA How life began and evolved Organisms: uniform at the molecular level indicate: they arose from a common ancestor,The main objectives are to understand,1. Protein Structu

5、re and Function* （蛋白质的结构和功能） 2. Enzymes: Basic Concepts and Kinetics (酶的基本概念及酶促动力学) 3. Enzymes: Catalytic the structure of proteins and other macromolecules; theories about molecular disease, such as sickle-cell anemia.,Some of Nobel Laureates in the historical development of Biochemistry,Krebs: Cit

6、ric Acid Cycle (TCA): an important way by which the complex chemical processes provide living organisms with high energy phosphate.,Sanger: Sequencing Method Amino acid sequencing method and the complete sequence of insulin. Sanger Sequencing Method for DNA,(Oswald Avery, Colin Macleod and Maclyn Mc

7、Carry),(有荚膜, S; 致病性）,Avery: DNA carries genetic material,（无荚膜, R； 非致病性）,S (heat-killed) Mouse lives,毒力株经加热灭活后会失去其致病性,R + S (heat-killed/ extracts) Mouse dies,结果小结和分析（背景：以往认为蛋白质携带遗传信息）,有荚膜的活细菌（S）：具致病性； 无荚膜的活细菌（R）：无致病性 S 菌株加热灭活后：无致病性 灭活后的 S 菌株 活细菌R：具致病性！ 提示S菌株中的遗传信息被导入活细菌R 该遗传信息对热不敏感，不是蛋白质 未知的物质携带了遗传信

8、息！,DNA carries the genetic information,1869, Miescher isolates nuclei,1944, Avery discovers that DNA carries the genetic material,1953, Watson and Crick propose the double-helical structure of DNA,Various process concerned with DNA. ex. semi-conservative replication.,DNA, RNA and Protein synthesis,S

9、. Ochoa and double or triple bonds between two C atoms. Covalently linked C atoms can form different structures （linear, branched, or cyclic） adding functional groups conferring specific activities to the molecules.,Versatility of carbon in forming covalent bonds,Organic compounds: Molecules contain

10、ing covalently bonding carbon backbones; e.g. alcohols, amines, aldehydes (醛), ketones, 羧基, 巯基, etc Most bio-molecules are organic compounds. “C” : tetrahedral arrangement of its four single bonds. C - C single bonds have freedom of rotation, but not double nor triple bonds. No other chemical elemen

11、t has the capacity to form molecules of such widely different sizes, shapes, with variety of functional groups, Most biomolecules can be considered to be derived from hydrocarbons hydrophilic interactions between biomolecules,Hydrocarbons,fisher,Ball-and-stick,Space filling,Bio-molecules have 3-D st

12、ructures,Bio-molecules have 3-D structures,The special feature of organic compounds is NOT their compositions but the way their atoms are combined (structures, 1820s) Corollary: two substances may show the same chemical formula but physically and chemically different materials (different structures

13、and functions).,Convention used for configuration,Light absorbing pigment in rhodopsin an integral membrane protein,Chiral：手性,Interactions between bio-molecules are stereo-specific,Between pairs of enantiomers 对映(结构)体： usually only one form is biologically active. L-amino acids (S) are found in prot

14、eins D-glucose (R) is biologically active Only one chiral form is generated in living cells due to enzyme specificity (1975 Nobel Prize) In contrast: the two enantiomers are usually synthesized in equal amounts in vitro chemical synthesis,Convention from organic chemistry,Chewing gums,绿薄荷,香菜,Two ste

15、reoisomers may have totally opposite biological effects (e.g., Chewing gums),Neutral sweet 天冬酰苯丙氨酸甲酯,Aspartame, a sugar substitute; its stereoisomer, bitter,Four families: Amino acids；Sugar； Fatty acids；Nucleotides Functions: Used to synthesize larger molecules； Have special biological functions； In

16、volved in complex reaction pathways；,Major Classes of Small Bio-molecules,Five general types of reactions in cells: Oxidation-reduction (氧化还原反应) Internal re-arrangements (isomerization, 异构) Cleavage Synthesis (increasing order, thus energy consuming) to provide building materials, anabolism.,The Rol

17、es of metabolism,Extract energy and reducing power from the environment (生命体通过光合作用和氧化作用从外界吸收能并释放废弃物）,Generation (interconversion) of all the biomolecules for a living organism (biosynthesis).（伴随着物质和能量代谢，生物分子间通过分解和合成作用发生互换）,Anabolism 合成代谢,Catabolism 分解代谢,能源物质,中间代谢产物,废弃物,General Features of metabolism

18、,linear, branched or circular pathways;,Highly interconnected 各个途径相互交接，形成物与能的网络化交流系统,Tightly regulated to achieve best economy 精密调控机制保证机体最经济的利用物质和能量,All living organisms are made up of cells, the smallest unit both the structural and functional of living matters. Cells are capable of self-reproducti

19、on. Most cells are microscopic in size Eukaryotic cells: 5 - 100 mm in size； bacteria: 1-2 mm; mycoplasma: 0.3 mm,Cell: Fundamental Unit of Life,Prokaryotic (原核）cells: Lack a nucleus e.g., Eubacteria and archaea Simple structure; Abundant specialized functions such as muscle contraction and nerve im

20、pulse conduction,Plasma membrane is a lipid bilayer composed of lipid and protein molecules,Others： Peroxisomes过氧化物酶体 Chloroplasts叶绿体 The cytoskeleton system etc,A rough analogy between the the cell and the human society,Nucleus: the highest administrative section. Mitochondria and chloroplasts: the

21、 power plant. Golgi Apparatus: the post office Cytoskeleton system: the highways (transportation) Lysosomes: the recycling center ER: the factory，training & education center Plasma membrane: the border line Like the society, the cytoplasm is crowded, highly organized, and dynamic.,2004年世界十大科技进展新闻是：1

22、.“勇气”&“机遇”号发现火星有水的证据,It is NOT an accident that life arose in association with water, since this substance has several unusual properties that suits to be the medium of life Thermal properties Solvent characteristics,Water: Medium of Life,Thermal Properties: Waters melting & boiling points are excep

23、tionally high compared with related molecules of similar molecular weight,Waters high heat of vaporization and high heat capacity make it an effective modulator of climatic temperature Water plays an important role in the thermal regulation of living organisms helps maintain an organisms internal te

24、mperature,Hydrogen bonding is responsible for this anomalous behavior Each water molecule can form hydrogen bonds with four other water molecules,Solvent Properties of Water,Waters dipolar structure and its capacity to form hydrogen bonds enable water to dissolve many ionic and polar substances Salt

25、s Organic molecules with ionizable groups or with polar functional groups,Noncovalent Bonding, Hydrogen Bonds Electrostatic interactions Van der Waals forces Hydrophobic interactions,Hydrogen Bonds,Electrostatic Interactions,Electrostatic interactions occur between oppositely charged atoms or groups To determine the shape and function of biomolecules Three-dimensional structure of protein Hydration of ions,Electrostatic interactions between charged groups or polar groups on biomolecules are most significant in water depleted region