FCAT Grade 8 Science Assessment Practice Questions

Answer: C - Human brain cells (neurons)require about two times more energy than any other cells in the body. Because the neurons are always active, a constant fuel source is required. Neurons use glucose as their source of energy; however,neurons do not possess glucose storage capabilities. The brain receives its fuel supply by a rich network of blood vessels. When blood glucose levels drop, the brain isaffected long before other symptoms of hypoglycemia (low blood sugar) manifest. Recent studies found glucose levels dropped significantly in students involved in complicated mental tasks; as the glucose level dropped, so did the students’ ability to study-an indication of the energy needed for studying!