Biochemistry (I & II)
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The aim of study: To be able to read what is not written and to hear what is not said! -----Zengyi Chang http://www.bio.pku.edu.cn/lab/proteinsci/
Biochemistry (I & II) Foundations and overview
Definition of Biochemistry
Biochemistry: seeks to understand the structure, organization, and function of living matter in chemical terms.
Kinds of questions asked by biochemists
Three principle areas of Biochemistry
Many drugs were designed as a result of our biochemical understanding of living organisms
History of Biochemistry
Some major events in the history of Biochemistry
The major types of biomolecules were revealed
Biochemistry is interdisciplinary
Biochemistry: a modern science of interdisciplinary nature
Biochemistry: Draws its major themes from many other fields
Biochemistry draws its major themes from other fields (Cont)
Nobel prizes for Biochemical studies
A remarkable number of Nobel prizes have been won by biochemists
Nobel Prizes in revealing the structural chemistry of living matter (1)
Nobel Prizes in revealing the structural chemistry of living matter (2)
Nobel Prizes in revealing the structural chemistry of living matter (3)
Nobel Prizes in revealing the structural chemistry of living matter (4)
Nobel Prizes in revealing the structural chemistry of living matter (5)
Nobel Prizes in revealing the structural chemistry of living matter (6)
Nobel Prizes in revealing the structural chemistry of living matter (7)
Nobel Prizes in revealing the Metabolism of living matter (1)
Nobel Prizes in revealing the Metabolism of living matter (2)
Nobel Prizes in revealing the Metabolism of living matter (3)
Nobel Prizes in revealing the information pathway (1)
Nobel Prizes in revealing the information pathway (2)
Nobel Prizes in inventing important methods for biochemical studies
Books on the history of Biochemistry: 1. 昌增益（译者）《蛋白质、酶和基因：化学与生物 学的交互作用》，清华大学出版社，2005年1月。 Fruton, J. S. (1999). Proteins, Enzymes, Genes: The Interplay of Chemistry and Biology. New Heaven and London: Yale University Press. （electronic version of this book is available in the library of Peking University). 2. 昌增益（译者） 《二十世纪生物学的分子革命：分 子生物学所走过的路》，科学出版社，2002年2 月。
The Foundations of Biochemistry (Chapters 1-2)
Living organisms are classified into various types
Organisms can also be classified based on their biochemical differences (energy and carbon sources)
Living organisms differ from inanimate objects in certain aspects
Structure of prokaryotic and eukaryotic Cells
Cells are the basic structural and functional life units where biomolecules are produced (and degraded) and function, with thousands of biochemical reactions occur in regulated ways.
Prokaryotic (“before nucleus”) cells lack an internal membrane system (i.e., having no organelles).
Eukaryotic cells have evolved a complicated internal membrane system, thus forming all kinds of organelles including a nucleus.
Cellular components are first isolated for biochemical studies
Life molecules are made of six principle elements : C, H, N, O, P, and S. (revealed by around the end of the first half of 19th century)
Life molecules are made around carbon.
Carbon is extremely versatile in forming covalent bonds with other atoms or itself
Carbon compounds are three dimensional!
A carbon-based biomolecule may have stereoisomers of different configuration or conformation
Configuration may result from the presence of a C=C bond
Enantiomers, discovered by Louis Pateur in 1848, demonstrate almost identical chemical properties, but rotate the plane of plane-polarized light in opposite directions with the same degree of rotation; racemic mixtures show no such optical activity.
A molecule having n asymmetric carbons may have 2n stereoisomers
A biomacromolecule usually exhibit a limited number of stable conformations among the many possible ones
The function of a biomolecule usually depends on its specific tree-dimensional structure, a combination of its configuration and conformation.
Carbon-based biomolecules vary in sizes: from small ones to biomacromolecules (biopolymers)
Biomolecules interact covalently and noncovalently
Interactions between biomolecules are usually stereospecific
Five general types of chemical transformations occur in living organisms
Oxidation-reduction: reactions involve electron transfers.
Nucleophilic substitution reactions involve the attack of an electron-rich nucleophile towards an electron-poor center.
Isomerization reactions involve electron transfers within the same molecule.
Group transfer reactions are common for activating metabolic intermediates
Condensation reactions join two molecules into one
Energy for life
Cells are consummate transducers of energy! The flow of electrons (i.e., oxidation-reduction reactions) provides energy for organisms.
The common form of energy for life is free energy (G)
Interaction between biomolecules are usually understood in thermodynamic and kinetic terms.
The thermodynamics and kinetics for a chemical reaction deal with its free energy change and activation energy respectively.
Noncovalent interactions between biomolecules are essential to life
Genetic Foundations The information to make functional proteins are stored in DNA and expressed via RNA.
Water and life
Life has been evolved in water
Water is central to biochemistry
Organic biomolecules are believed to be produced abiotically early on the earth
Biomolecues first arose by chemical evolution before subject to biological evolution: Building blocks of biomacromolecules need to be formed during prebiotic evolution.
Some scientific journals and organizations in the field of Biochemistry
Instructors for Biochemistry I
Teaching Assistants: 康瑞玉:email@example.com; 陈方圆faye@pku.edu.cn； 雷剑leijian@pku.edu.cn
Textbook and reference books
Grading policy for Biochemistry I
Enjoy the molecular trip of life! Please study with a historical perspective, an interdisciplinary spirit, and a questioning mind.
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