Three groups of drugs are used to reduce the stickiness of platelets, thus preventing platelets from clumping together to form platelet plugs. The anti-platelet drugs are most effective in preventing abnormal blood clots from forming in arteries (as opposed to veins). Aspirin and dipyridamoleâ (Aggrenox).
In order to react, colliding molecules must have a total kinetic energy equal to or greater than some minimum value [Figure 14.13(b)]. The minimum energy required to initiate a chemical reaction is called the activation energy, Ea. The value of Ea varies from reaction to reaction.
Enzymes & the Need for Energy. 1: Enzymes. â¢ Catalysts: substances that speed up chemical reactions without being affected by the reactions themselves. â¢ Enzyme: a protein that increases the rate of reactions by lowering the activation energy. â¢ Activation Energy: the amount of energy needed to start a chemical reaction.