Final answer:
Glycogen synthesis (glycogenesis) and glycogen breakdown (glycogenolysis) are two opposing processes that are usually not active at the same time due to hormonal regulation, making the statement false.
Step-by-step explanation:
The statement that glycogen synthesis and glycogen phosphorylase can happen simultaneously is false. Glycogen synthesis, or glycogenesis, is the process of forming glycogen from glucose. This involves multiple enzymes, starting with glucose being trapped in the cell as glucose-6-phosphate and eventually forming UDP-glucose. Glycogen phosphorylase, on the other hand, is the enzyme responsible for the breakdown of glycogen into glucose-1-phosphate during glycogenolysis.
Synthetic pathways like glycogenesis are typically active during states of abundant energy and are suppressed when energy needs to be released, such as during fasting or intensive exercise. Conversely, glycogenolysis is upregulated to release glucose when energy is needed. The activities of these processes are tightly regulated and influenced by hormonal signals, such as insulin promoting glycogenesis, while glucagon and epinephrine activate glycogenolysis. Therefore, these two processes are generally not active simultaneously as the cell regulates them to either store or release glucose as needed.