Final answer:
An enzyme is a biological catalyst that speeds up biochemical reactions without being consumed, playing a vital role in digestion and metabolic processes. Enzyme deficiencies or malfunctions can lead to diseases like phenylketonuria.
Step-by-step explanation:
An enzyme is a protein that acts as a biological catalyst. It speeds up biochemical reactions by lowering the activation energy needed for the reaction to proceed. Enzymes are essential for maintaining life's processes, as they are involved in most of the chemical reactions within organisms.
For instance, enzymes are integral in the digestion process, where they help break down complex food molecules into simpler nutrients that the body can absorb. Moreover, a deficiency in a specific enzyme's production or function can lead to metabolic disorders, as enzymes are highly specific and can only catalyze certain types of reactions. An example of a health consequence due to enzyme malfunction is phenylketonuria, which results from the inability to break down the amino acid phenylalanine.
Since enzymes are not consumed during the reactions they facilitate, they are available to catalyze multiple rounds of the same reaction. This characteristic makes enzymes indispensable in regulating various biochemical pathways critical for health and disease management.