Final answer:
The average time between synthesis and breakdown is known as the turnover time, a concept that plays a key role in understanding protein and enzyme metabolism, where proteins have different turnover rates based on their function and enzymes have specific turnover numbers.
Step-by-step explanation:
The average time between synthesis and breakdown is known as the turnover time. This concept is crucial in understanding protein turnover, which refers to the balance between protein synthesis and protein degradation. Not all amino acids required for biological functions need to be obtained through the diet, as the body can recycle proteins that have already served their purpose in metabolism. Proteins have varying turnover rates, with structural proteins such as collagen having a long half-life and enzymes having shorter half-lives to quickly adapt to the body's metabolic needs.
Metabolism is the sum of all catabolic and anabolic reactions in the body. Both these processes occur simultaneously, with anabolic reactions involving the synthesis of compounds and catabolic reactions involving their breakdown. The rate at which this occurs is tied to the body's metabolic rate, which indicates the amount of energy needed to sustain life. The idea of turnover also applies to enzymes, where the enzyme turnover number refers to the amount of substrate molecules an enzyme can convert per unit of time.