7.1 芳香烃的分类 结构及命名 Classification, Structures and Nomenclature of Aromatic Compounds 7.2 芳香烃的来源及物理性质 Sources and Physical Properties of Aromatic Hydrocarbons
Of the three groups of biopolymers, protein have the most diverse function. Most of its molecular weights are much larger. Their shaps cover a range from the globular protein to the helical coils of a α–keratin. But all proteins have common features. Proteins are polyamides and their monomeric units are about 20 different α-amino acids
The nucleic acids, deoxyribonucleic (DNA) and ribonucleic (RNA) , are, respectively , the molecules that preserve hereditary information and that transcribe and translate it in a way that allows the synthesis of all the varied proteins of the cell 25.2 NUCLEOTIDES AND NUCLEOSIDES
The important of acid-base reaction: 1. is a simple, fundamental reaction. 2. enable you to see the mechanism of the reaction 3. illustrate the process of bond breaking and bond making 4. examine important ideas about the relationship between the structure of molecules and their reactivity
Chapter 6 Ionic Reactions--- Nucleophilic substitution and elimination reactions of alkylhalides (卤代烃的亲核取代反 Because halogen atoms are more electronegative 应和消除反应） than carbon, the carbon-halogen bond of alkyl halides is polarized; the carbon atom bears a partial positive charge, the halogen atom a partial negative charge
1.1 Distinctive Properties of Living Systems 1.2 Biomolecules: The Molecules of Life 1.3 A Biomolecular Hierarchy: Simple Molecules Are the Units for Building Complex Structures 1.4 Properties of Biomolecules Reflect Their Fitness to the Living Condition 1.5 Organization and Structure of Cells 1.6 Viruses Are Supramolecular Assemblies Acting as Cell Parasites
Valence & Hybridization The number of atoms which are typically bonded to a given atom is termed the valence of that atom. Thus, in the examples shown below, hydrogen would have a valence of one, oxygen would have a valence of two, nitrogen and boron would have a valence of three
