What is the process of converting glycogen to glucose called?

Correct Answer: B

Rationale: The correct answer is B: Glycogenolysis. Glycogenolysis is the process of breaking down glycogen into glucose. Choices A, C, and D are incorrect. Glucogenesis (choice A) is not a term used in biochemistry. Glyconeogenesis (choice C) refers to the synthesis of new glucose molecules from non-carbohydrate sources, not the breakdown of glycogen. Gluconeogenesis (choice D) is the process of producing glucose from non-carbohydrate sources, not the breakdown of glycogen.

Correct Answer: C

Rationale: The correct answer is C: water. Water is the main component of blood plasma, interstitial fluid, and intracellular fluid. It plays a crucial role in various bodily functions, including transporting nutrients, regulating body temperature, and maintaining cell structure. Choices A, B, and D are incorrect because while potassium, sodium, and calcium are essential electrolytes found in the body, they are not the main constituents of these fluids as water is.

Correct Answer: D

Rationale: The correct answer is D: Hydrochloric acid. Hydrochloric acid in the stomach plays a crucial role in converting pepsinogen into its active form, pepsin, which is necessary for digesting proteins. Bile (Choice A) is involved in the emulsification of fats, not in the activation of pepsinogen. Gastrin (Choice B) is a hormone that stimulates the secretion of gastric acid but does not directly activate pepsinogen. Secretin (Choice C) is a hormone that regulates the pH of the duodenum but is not responsible for the activation of pepsinogen.

Correct Answer: A

Rationale: Cholecystokinin (CCK) is produced in the duodenum, not the stomach, pancreas, or liver. It is released in response to the presence of food in the duodenum, where it plays a crucial role in regulating digestive processes by stimulating the release of bile from the gallbladder and enzymes from the pancreas. Therefore, the correct answer is the duodenum (Choice A). Choices B, C, and D are incorrect because CCK is not produced in the stomach, pancreas, or liver.

Correct Answer: C

Rationale: The correct answer is C: 'presence of food in the stomach.' Gastric secretions are stimulated when food enters the stomach, triggering nerve and hormonal responses. This process prepares the stomach for digestion. Choices A, B, and D are incorrect because ingesting water, swallowing reflex, and the closing of the pyloric sphincter do not directly stimulate the release of gastric secretions.

Correct Answer: C

Rationale: Gluconeogenesis mainly occurs in the liver. It is a process where glucose is synthesized from non-carbohydrate sources such as amino acids and glycerol. The liver is the primary site for gluconeogenesis due to the presence of key enzymes and substrates required for this process. Muscles do not play a significant role in gluconeogenesis, making choice A incorrect. The pancreas is involved in the regulation of blood sugar levels through insulin and glucagon but is not the primary site for gluconeogenesis, so choice B is incorrect. The spleen is not a major organ involved in glucose metabolism, making choice D incorrect.

Correct Answer: D

Rationale: The correct answer is D: Absorption of water. The primary nutritional function of the large intestine is to absorb water from the indigestible food residue that enters it from the small intestine. This absorption of water helps to form solid waste, which is then eliminated from the body. Choices A, B, and C are incorrect because the large intestine is not primarily responsible for the absorption of fats, excretion of waste products, or excretion of bacteria. While the large intestine does play a role in waste elimination and contains bacteria beneficial for digestion, its main function in terms of nutrition is the absorption of water.

Correct Answer: B

Rationale: In a low-carbohydrate diet, fats become the primary source of calories as carbohydrate intake is restricted. Proteins can contribute to caloric intake but are not the primary source in a low-carbohydrate diet. Carbohydrates are intentionally limited in this diet, so they do not supply most of the calories. Vitamins are essential nutrients but do not provide calories.

Correct Answer: D

Rationale: The correct answer is D, 'Mastication.' Mastication is the mechanical process of chewing that breaks down food into smaller particles. Peristalsis (choice A) is the involuntary constriction and relaxation of muscles in the gastrointestinal tract that moves food along. Segmentation (choice B) is the mixing movement of the digestive system that helps to break down food and mix it with digestive juices. Metabolism (choice C) refers to the chemical processes that occur within a living organism to maintain life.