Rational drug design involves the development or modification of a drug that is desinged to interact with a specific biological molecule, the biotarget, to provide a therapeutic benefit. many of these drugs are designed to activate or inhibit lipids, enzymes, nerve cells or nucleic acids

The correct answer is this: Many of these drugs are designed to activate or inhibit ENZYMES.

Enzymes are the biological catalyst that increase the speed at which biochemical reactions take place in living things. Most enzymes are proteins. Rational drug design usually target enzymes because they take part in all biochemical reactions that occur in living organisms. By inhibiting or activating an enzyme, a drug can be designed to carry out a particular function or to have particular effects.

The answer is enzymes.

Enzymes are macromolecular biological catalysts. Enzymes accelerate, or catalyze, chemical reactions. The molecules at the beginning of the process are called substrates and the enzyme converts these into different molecules, called products. Almost all metabolic processes in the cell need enzymes in order to occur at rates fast enough to sustain life.

it provides an alternative energy pathway for the reaction to proceed.

a catalyst is a substance that speeds up the rate of a chemical reaction but is not consumed during the course of the reaction.

catalysts increase the rate of reaction without being used up. they do this by lowering the activation energy needed. with a catalyst, more collisions result in a reaction, so the rate of reaction increases. different reactions need different catalysts.

a catalyst works by providing an alternative reaction pathway to the reaction product. the rate of the reaction is increased as this alternative route has a lower activation energy than the reaction route not mediated by the catalyst.