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什么是代谢?
Metabolism represents all of the chemical activity in a cell, including reactions that build molecules (anabolism) and those that break molecules…
热力学第一定律
The First Law of Thermodynamics states that energy cannot be created or destroyed, only transformed. This can be demonstrated within a classic food…
热力学第二定律
The Second Law of Thermodynamics states that entropy, or the amount of disorder in a system, increases each time energy is transferred or…
动能
Kinetic energy is the ability of an object in motion to do work or enact change. It can take on many forms. For instance, water flowing down a…
势能
Potential energy is a stored form of energy that has the potential to do work, and therefore, to be converted into kinetic energy. Gravitational…
自由能
Free energy—abbreviated as G for the scientist Gibbs who discovered it—is a measurement of useful energy that can be extracted from a…
活化能
Activation energy is the minimum amount of energy necessary for a chemical reaction to move forward. The higher the activation energy, the slower the…
ATP水解
The bonds of adenosine triphosphate (ATP) can be broken through the addition of water, releasing one or two phosphate groups in an exergonic process…
磷酸化
The addition or removal of phosphate groups from proteins is the most common chemical modification that regulates cellular processes. These…
诱导契合模型
Most chemical reactions in cells require enzymes—biological catalysts that speed up the reaction without being used up or permanently changed.…
酶促反应动力学
Enzymes speed up reactions by lowering the activation energy of the reactants. The speed at which the enzyme turns reactants into products is called…
酶抑制
Inhibitors are molecules that reduce enzyme activity by binding to the enzyme. In a normally functioning cell, enzymes are regulated by a variety of…
反馈抑制
Biochemical reactions are occurring constantly in cells, converting starting substances to different products, usually with the help of enzymes that…
变构规则
Allosteric regulation of enzymes occurs when the binding of a molecule to a different location from the active site causes a change in enzymatic…
辅助因子和辅酶
Enzymes require additional components for proper function. There are two such classes of molecules: cofactors and coenzymes. Cofactors are metallic…
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