Final answer:
Enzyme regulation and turnover are responsible for the disappearance of enzymes from a cell if they are not continually synthesized. These mechanisms ensure that enzymes are produced according to the cell's current needs and conditions, and without them, vital biochemical reactions would not occur efficiently.
Step-by-step explanation:
Because of enzyme regulation and turnover, unless an enzyme is synthesized in an ongoing manner, the enzyme will disappear from the cell. Enzymes are vital for life as they catalyze biochemical reactions within the body, allowing processes to occur at rates sufficient for survival. Without the constant synthesis or regularization of these enzymes, reactions would slow down significantly or even stop, leading to cellular dysfunction.
Enzymes can be classified as inducible enzymes, which are synthesized when needed, and constitutive enzymes, which are always present. Factors such as binding with substrate molecules, presence of metabolic activators or inhibitors, and cellular conditions influence enzyme activity and quantity. For example, a cell's metabolic needs after a meal differ significantly from those many hours later, and the types and levels of enzymes reflect this.