Is this sentence correct?

Question

During periods of low levels of glucose in the blood, skeletal muscle cells use their glycogen stores to increase blood glucose levels.

Answer 1

No, I would actually say that sentence is incorrect! During the fasting state, blood sugar drops (hypoglycemia). As a result, the body must dip into its carbohydrate stores. The main place that this happens is the liver.

Once glycogen is broken down with various enzymes, you end up with glucose-6-phosphate (G6P). This is a glucose molecule with a phosphate group attached. To get that (G6P) out of the cells, you need to use Glucose-6-Phosphatase enzyme to remove the phosphate group. The liver has this enzyme, but skeletal muscles do not.

The end result is that any glycogen stored in skeletal muscle can only be used by that skeletal muscle, not by the rest of the body. It is a way that the muscles can "hoard" energy to use later!