Final answer:
The claim that protein synthesis peaks between 45-90 minutes after eating and then returns to baseline by 180 minutes is false. Protein turnover is a constant process involving both synthesis and degradation, and the timing of peak synthesis can vary widely based on various factors.
Step-by-step explanation:
The statement that protein synthesis peaks at 45-90 minutes following a meal and returns to baseline at 180 minutes is false. Protein synthesis is indeed a rapid process, with amino acids being added to the peptide chain at a rate of 3-5 per second. An important aspect of protein metabolism is protein turnover, which is the balance between protein synthesis and degradation. This ongoing turnover implies that proteins of the body are regularly replaced. While individual amino acids from a meal can be quickly used for new protein synthesis, the notion that protein synthesis has a sharp peak and then declines to baseline within a short, fixed time frame is an oversimplification.
Protein synthesis is critical because proteins carry out nearly every function of a cell, from structural support to catalyzing metabolic reactions as enzymes. The half-life of proteins can vary significantly, with some lasting only minutes while others can last for years. This variability means that the timing of peak protein synthesis can depend on many factors, including the type of protein and cellular demand. Furthermore, dietary amino acids support the synthesis of new proteins as part of an ongoing process, rather than eliciting a single, acute peak in synthesis after a meal.