Because they lower the activation energy that is needed for reactions to take place faster in the body. Many reactions in the body would take place without enzymes, but at a speed that would not be conducive to biochemical processes needed in the body. So, enzymes are the bodies answer to reaction speed up.
Yes, that is exactly what an enzyme is.
an enzyme
Biological catalyst
an enzyme
enzyme
A biological catalyst is an enzyme, enzyme are found all over living things, each with specific use
DNA helicase. This is the enzyme that "unzips" DNA.
It is acting as a biological catalyst.
enzyme
biological catalysts
biological catalyst
Enzyme