In what form is glucose stored in muscle and liver?

In what form is glucose stored in muscle and liver?

• A. Glycogen
• B. Maltose
• C. Lactose
• D. Starch

Answer: (A)

Glucose is stored in muscle and liver as glycogen, a highly branched polysaccharide that serves as a ready source of glucose when energy is needed. In the liver, glycogen helps maintain blood glucose levels between meals, releasing glucose to the bloodstream as needed. In skeletal muscle, glycogen provides a rapid internal energy reserve for muscle contraction during activity. The branching structure of glycogen creates many terminal ends, allowing quick synthesis and breakdown to glucose-6-phosphate for glycolysis. The liver has the enzyme glucose-6-phosphatase to convert G6P back to free glucose for release into the blood, while muscle lacks this enzyme, so glycogen breakdown in muscle fuels local energy production rather than blood glucose. This storage form is characteristic of animals; plants store glucose as starch. The other options are not storage forms in this context: maltose and lactose are disaccharides, and starch is the plant storage polysaccharide.

Glucose is stored in muscle and liver as glycogen, a highly branched polysaccharide that serves as a ready source of glucose when energy is needed. In the liver, glycogen helps maintain blood glucose levels between meals, releasing glucose to the bloodstream as needed. In skeletal muscle, glycogen provides a rapid internal energy reserve for muscle contraction during activity. The branching structure of glycogen creates many terminal ends, allowing quick synthesis and breakdown to glucose-6-phosphate for glycolysis. The liver has the enzyme glucose-6-phosphatase to convert G6P back to free glucose for release into the blood, while muscle lacks this enzyme, so glycogen breakdown in muscle fuels local energy production rather than blood glucose. This storage form is characteristic of animals; plants store glucose as starch. The other options are not storage forms in this context: maltose and lactose are disaccharides, and starch is the plant storage polysaccharide.