Nokea
The lining of the stomach and intestine is protected from self-digestion by:
- A. pepsinogen.
- B. bile.
- C. mucus.
- D. fat.
Correct Answer: C
Rationale: The correct answer is C: mucus. Mucus forms a protective barrier that prevents the stomach and intestine from digesting themselves. Pepsinogen (choice A) is an inactive form of pepsin, a digestive enzyme, and does not protect the stomach lining. Bile (choice B) aids in the digestion and absorption of fats but does not protect the stomach lining. Fat (choice D) is a nutrient and energy source; it does not play a role in protecting the stomach and intestine from self-digestion.
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After absorption, the end products of carbohydrate and protein digestion enter the:
- A. enterohepatic circulation.
- B. gastrointestinal circulation.
- C. common bile duct.
- D. portal blood system.
Correct Answer: D
Rationale: The correct answer is D: portal blood system. After absorption, carbohydrates and proteins are transported via the portal blood system to the liver for further processing and distribution to the rest of the body. Choices A, B, and C are incorrect. Enterohepatic circulation refers to the recycling of compounds between the liver and the intestines, not the direct route for absorbed nutrients. Gastrointestinal circulation is a vague and non-specific term, not specifically related to the transport of absorbed nutrients. The common bile duct is involved in transporting bile from the liver and gallbladder to the small intestine, not the end products of carbohydrate and protein digestion.
Which of the following is one of the simplest amino acids?
- A. Arginine
- B. Valine
- C. Lysine
- D. Glycine
Correct Answer: D
Rationale: Failed to generate a rationale of 500+ characters after 5 retries.
Feces are composed mainly of bacteria, mucosal cells, mucus, and what else?
- A. bile
- B. enzymes
- C. fiber
- D. chyme
Correct Answer: C
Rationale: The correct answer is 'C: fiber.' Feces are primarily made up of indigestible material, such as fiber. Bile (choice A) is produced by the liver to aid in digestion but is not a major component of feces. Enzymes (choice B) are involved in digestion but are not a significant component of feces. Chyme (choice D) is the semi-fluid mass of partially digested food that moves from the stomach to the small intestine and is not a major component of feces.
What is the term for the production of glucose from protein, lactate, or glycerol?
- A. glycolysis
- B. gluconeogenesis
- C. glycogenolysis
- D. glucogenesis
Correct Answer: B
Rationale: Gluconeogenesis is the correct term for the production of glucose from non-carbohydrate sources such as protein, lactate, or glycerol. Choice A, glycolysis, is the process of breaking down glucose into pyruvate. Choice C, glycogenolysis, is the breakdown of glycogen into glucose. Choice D, glucogenesis, is not a recognized term in biochemistry.
Which pathogenic bacterium is associated with peptic ulcer disease and gastric cancer?
- A. Lactobacillus.
- B. Bifidobacterium.
- C. H. pylori.
- D. E. coli.
Correct Answer: C
Rationale: The correct answer is H. pylori. This bacterium is known to be associated with the development of peptic ulcers and an increased risk of gastric cancer. Lactobacillus (Choice A) and Bifidobacterium (Choice B) are probiotic bacteria that are beneficial to human health and not associated with causing these conditions. E. coli (Choice D) is a diverse group of bacteria, some of which can be pathogenic, but they are not primarily linked to peptic ulcers and gastric cancer like H. pylori.