深圳大学生物化学下册生物能学-讲义

1.5 Transform of chemical energy (化学能的转化)
➢ 化学能和其它能量形式的转化。 ➢ 高能化合物→ 低能化合物+自由能+热 ➢ 物质氧化的不同途径：
①体外燃烧 ②生物氧化
Antoine Lavoisier, before he lost his head in the French Revolution, observed that “. . . in general, respiration is nothing but a slow combustion of carbon and hydrogen, which is entirely similar to that which occurs in a lighted lamp or candle.”
! 内能、焓、熵以及自由能的概念
1.1 System and surroundings （体系和环境）
➢System （体系、系统） ➢Surroundings（环境、外界） ➢open system(开放体系), closed systems(封闭 体系) , isolated systems (隔离体系) ➢Parameters of a system(体系的状态参数)
热：温差、质点无序运动 功：定向、有序的运动
1.3 Internal energy and Enthalpy (内能与焓)
➢Internal energy(内能，U或E, J/mol)：体系内 质点的能量。
➢Enthalpy(焓, H, J/mol)：焓包含体系内质点自 身的能量以及质点之间的相互作用。
深圳大学生物化学下册生物能学
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百度文库
易水寒江雪敬奉
1. 生物能学和热力学 2. 化学反应和自由能 3. 高能化合物
1. Bioenergetics and Thermodynamics （生物能学和热力学）
1.1 体系和环境 1.2 能的两种形式 1.3 内能与焓 1.4 热力学第一定律 1.5 化学能的转化 1.6 热力学第二定律和熵 1.7 自由能的概念
The entropy of the universe increases during all chemical and physical processes.
Living organisms are open system and in order. ?
Living organisms preserve their internal order by taking from the surroundings free energy in the form of nutrients or sunlight, and returning to their surroundings an equal amount of energy as heat and entropy.
energy matter
System
Surroundings
System+ Surroundings = Universe
Parameters of a system： 压力、体积、温度、组成、比热……
1.2 Two forms of energy (能的两种形式)
一个体系在状态发生改变时与环境交换能量 的两种形式：
3. 3.All naturally occurring processes proceed toward equilibrium, that is to a state of minimum potential energy
Entropy, (熵, S, J/mol•K ) is a quantitative expression for the randomness or disorder in a system.
ΔU = Q - W
➢Biological system is an open system (生物体系 是一个开放体系)
➢Biochemical processes are almost in condition of constant pressure and volume (生物化学过程 近似恒压、恒容过程) 由于 ΔH = ΔU + ΔPV 因此，生物化学中“能量变化” ≈ ΔH ≈ ΔU
1.6 The second law and Entropy (热力学第二定律和熵)
1. System tend to proceed from ordered states to disordered states.
2. 2.The entropy of the system plus surroundings is unchanged by reversible processes;the entropy of the system plus surroundings increases for irreversible processes.
熵（S）:代表体系能量分散程度的状态 函数，也就是代表体系质点散乱无序的程度。
ΔS = ΔQ/T >0
由于熵不易测量，用它判定生物化学反应过 程能否自发进行较为困难。 用自由能作为衡量标准可排除此困难。
1.7 Free energy（自由能）
➢Free energy (G) expresses the amount of energy capable of doing work during a reaction at constant temperature and pressure (自由能: 可以在恒温恒压下做功的能量.) ➢热能: 做功只能引起温度或压力变化；
ΔH = ΔU + ΔPV
1.4 The first law of thermodynamics (热力学第一定律)
The first law of thermodynamics is the principle of the conservation of energy: The total amount of energy in the universe remains constant, although the form of the energy may change.