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.
We can also study enzymes in the context of activation energy. Many biochemical reactions need a little input of energy to jump-start a thermodynamically favorable reaction. The activation energy is the amount of energy needed for the reaction to go forward and get over its activation barrier. ATP (adenosine triphosphate), the cellâs energy carrier, needs a little help to get over its activation barrier.