Final answer:
Proteins can contribute to maintaining blood glucose levels, ensuring adequate energy for the brain, which is true. Glucagon and insulin play key roles in regulating blood glucose levels by stimulating glycogen conversion and glucose uptake, respectively.
Step-by-step explanation:
The statement that protein can help to maintain a steady blood glucose level and therefore meet the glucose needs of the brain is true. When carbohydrate intake is inadequate, the body can utilize protein to produce glucose through a process known as gluconeogenesis. This serves to maintain blood glucose levels within a normal range, ensuring a steady supply of energy to glucose-dependent organs, such as the brain.
Glucagon plays a critical role in blood glucose homeostasis, particularly when blood glucose levels are low. Alpha cells of the pancreas secrete glucagon, which stimulates the liver to convert stored glycogen into glucose, thus increasing blood glucose levels. Conversely, when blood glucose levels become elevated after a meal, beta cells of the pancreas release insulin, prompting cells to take up glucose from the bloodstream and store it as glycogen in the liver, which reduces blood glucose levels.
In summary, both protein and the hormones insulin and glucagon are essential in maintaining blood glucose homeostasis. They respond to fluctuations in blood sugar levels to ensure that cells, particularly brain cells, have a constant supply of energy.