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.
Lesson Summary. The activation energy is the energy required to start a reaction. Enzymes are proteins that bind to a molecule (substrate) to modify it and lower the energy required to make it react. The rate of reaction is given by the Arrhenius equation. The rate of reaction increases if the activation energy decreases.