Final answer:
In the liver cells of a healthy individual, enzyme molecular size and total quantity vary in response to hormonal changes. Up-regulation occurs with an increase in hormone levels and receptors, enhancing cell activity, while down-regulation does the opposite. Cellular enzyme amounts and activity are tightly controlled and varied based on the cell type, environmental conditions, and hormonal interactions.
Step-by-step explanation:
In the normal liver cells from a healthy individual, the molecular size of the enzyme changes in response to hormones, while the total amount of enzyme also fluctuates. When hormone levels increase and the number of target cell receptors increase, this results in a process known as up-regulation, enhancing the cell's sensitivity and activity towards the hormone. Conversely, when hormone levels increase but the number of receptors decrease, this is referred to as down-regulation, effectively diminishing the cellular response. Such regulatory mechanisms are crucial for maintaining homeostasis and are evident across various cell types, including liver cells, which play a vital role in metabolism and detoxification.
The relative amounts and functioning of enzymes are controlled by cellular demands and environmental factors, such as pH and temperature. Furthermore, hormones like insulin can change a cell's permeability, whereas others, like epinephrine, function through a second messenger such as cAMP (cyclic Adenosine Monophosphate), which can either activate or inhibit certain enzymes, tailoring the cellular response.