An enzyme is a biological catalyst that is usually a protein but could be RNA. The point of a catalyst is to increase the speed with which a reaction happens. And there are many enzymes that are encoded by the genome to make proteins or RNAs that speed up various chemical reactions to do thousands of different functions inside a cell.

In simple terms, enzymes speed up chemical reactions by helping molecules meet and interact the right way.

For example:

1. Enzymes in your saliva break down starches into sugar.
2. Enzymes in your cells copy DNA during cell division.
3. Enzymes in plants help turn sunlight into energy during photosynthesis.

Enzymes are fast because they:

1. Lower activation energy they reduce the energy needed to start a reaction.
2. Bring the right molecules together like a matchmaker for chemistry.
3. Use precise shapes they fit their target molecules (called substrates) like a key in a lock.

Some enzymes can catalyze thousands of reactions per second an impressive speed for a molecule that you can’t even see with a regular microscope.

First, a substrate (the molecule to be transformed) binds to the enzyme’s active site, forming an enzyme-substrate complex. This temporary structure allows the enzyme to perform its catalytic function.

The substrate is then converted into products, which are released, leaving the enzyme unchanged and ready to catalyze another reaction.

This cycle shows how enzymes work quickly and efficiently to support countless biological processes in cells.

1. In your brain: for neurotransmitter synthesis.
2. In your blood: to help clot wounds.
3. In your muscles: to generate energy during movement.
4. In plants: to capture sunlight and make sugar.
5. In labs and industries: used in PCR, detergents, food processing, and more.

Enzymes are the silent engines of life, driving chemical reactions that would otherwise be far too slow to sustain living systems. From digesting food to building DNA, enzymes work with incredible speed, precision, and efficiency. Their unique ability to lower activation energy and remain unchanged after use makes them some of the most powerful tools in biology.

Whether you're studying cells in a lab or simply enjoying a meal, enzymes are hard at work behind the scenes making life happen at just the right pace.