Where is glycogen stored?

Correct Answer: C

Rationale: The correct answer is C: liver. Glycogen is primarily stored in the liver and muscles. The liver serves as a major storage site for glycogen, acting as a reservoir for glucose when blood sugar levels drop. The pancreas (A) mainly produces digestive enzymes and hormones like insulin and glucagon. The small intestine (B) is involved in nutrient absorption, not glycogen storage. The large intestine (D) is mainly responsible for absorbing water and electrolytes, not storing glycogen. Therefore, C is the correct answer.

Correct Answer: C

Rationale: The correct answer is C: fat droplets. When the liver is unable to break down red blood cells, it affects the metabolism of hemoglobin, leading to decreased production of bile salts necessary for emulsifying fats. This results in decreased production of fat droplets. A: Maltose is a disaccharide formed from the breakdown of starch, not directly related to red blood cell breakdown. B: Peptides are formed from protein digestion, not directly affected by the breakdown of red blood cells. D: Nucleotides are building blocks of nucleic acids and not directly related to red blood cell breakdown.

Correct Answer: C

Rationale: The correct answer is C because salivary glands secrete an enzyme called amylase that catalyzes the breakdown of carbohydrates into maltose. Amylase specifically targets the bonds between glucose molecules in carbohydrates, resulting in the production of maltose. Therefore, the reaction of carbohydrates + H2O -> maltose is catalyzed by salivary gland secretions. Choice A is incorrect because the breakdown of proteins into peptides is not catalyzed by salivary gland secretions. Choice B is incorrect as peptides are broken down into amino acids, not the other way around. Choice D is incorrect as the breakdown of fats into fatty acids and glycerol is not catalyzed by salivary gland secretions.

Correct Answer: A

Rationale: The correct answer is A because during protein digestion, specific enzymes such as proteases break down proteins into amino acids. Proteins are large molecules made up of amino acids, and the body needs to break them down into individual amino acids for absorption and utilization. Choices B, C, and D are incorrect because hormones do not directly break down proteins, and proteins are not broken down into simple sugars or complex starches during digestion. It is essential to understand the role of enzymes in protein digestion to select the correct answer.

Correct Answer: C

Rationale: Rationale for Correct Answer C: 1. Glycogen is a polysaccharide composed of glucose units. 2. It is synthesized and stored in the liver and muscles. 3. Liver glycogen is used to maintain blood glucose levels. 4. Muscle glycogen is used for energy during physical activity. Summary of Incorrect Choices: A: Red blood cells do not store glycogen; they lack organelles. B: Glycogen is not a protein; it is a carbohydrate. D: Glycogen is not a by-product of sucrose digestion; it is a stored form of glucose.