Which enzyme initiates protein digestion in the stomach?
- A. Pepsin
- B. Salivary Amylase
- C. CCK
- D. Secretin
Correct Answer: A
Rationale: Pepsin is the enzyme that initiates protein digestion in the stomach. It breaks down proteins into smaller peptides, aiding in their further digestion and absorption in the intestines. Salivary Amylase (Choice B) functions in breaking down dietary carbohydrates in the mouth, not proteins. CCK (Choice C) and Secretin (Choice D) are hormones involved in the digestion of fats and carbohydrates, not proteins. Therefore, Choices B, C, and D are incorrect in the context of protein digestion in the stomach.
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Where in the body are microvilli located, facilitating the absorption of most nutrients?
- A. Stomach
- B. Pancreas
- C. Large Intestine
- D. Small Intestine
Correct Answer: D
Rationale: The correct answer is D: Small Intestine. Microvilli are present in the small intestine, significantly increasing its surface area for efficient absorption of nutrients. The small intestine is the primary site for nutrient absorption in the body. The stomach (choice A) primarily functions to break down food with its acidic environment but is not where most nutrients are absorbed. The pancreas (choice B) produces enzymes to aid in digestion but does not directly absorb nutrients. The large intestine (choice C) mainly absorbs water and electrolytes from undigested food, rather than nutrients.
Which chemical structure is represented by glycerol combined with two fatty acids?
- A. Compound lipids
- B. Monoglycerides
- C. Diglycerides
- D. Structural lipids
Correct Answer: C
Rationale: The correct answer is C: Diglycerides. A diglyceride is a glycerol molecule combined with two fatty acids. This is a common form of fat during digestion and absorption. Choice A, Compound lipids, is incorrect because these lipids are composed of simple lipids plus additional compounds, which is not the case with a glycerol molecule combined with two fatty acids. Choice B, Monoglycerides, is incorrect because these are glycerol molecules combined with only one fatty acid, not two. Lastly, choice D, Structural lipids, is incorrect because these are major components of cell membranes and do not directly relate to the combination of glycerol and two fatty acids.
Which of the following statements are true about iron?
- A. The iron needs of vegans are 20% higher, and the needs of endurance athletes are 10% lower.
- B. It is one of the most common nutrient deficiencies in the world.
- C. Its absorption is increased by Vitamin C and during pregnancy.
- D. Its absorption is increased by tannic acid and calcium in milk.
Correct Answer: C
Rationale: Choice C is correct because iron absorption is indeed increased by Vitamin C and during pregnancy. The other choices are incorrect. Choice A is wrong as there are no universally accepted percentages for the iron needs of vegans and endurance athletes. Choice B is inaccurate as iron deficiency is actually one of the most common nutritional deficiencies worldwide. Choice D is incorrect because tannic acid and calcium in milk actually inhibit iron absorption rather than increasing it.
In which condition is underconsumption of fat not a concern?
- A. Malabsorption syndromes
- B. Cystic fibrosis
- C. AIDS
- D. Hypertension
Correct Answer: D
Rationale: The correct answer is D, Hypertension. Hypertension is not typically associated with underconsumption of fat; instead, it is more related to the consumption of excess fat, especially saturated and trans fats, which can contribute to increased blood pressure. Malabsorption syndromes, cystic fibrosis, and AIDS are conditions where underconsumption of fat can be a concern due to various reasons such as malabsorption issues, pancreatic insufficiency, or increased energy needs.
What are the potential consequences of damage to the stomach?
- A. Reduced digestion of carbohydrates
- B. Inability to produce or secrete bile
- C. Inability to produce or secrete gastric acid
- D. Increased ability to produce or secrete intrinsic factor
Correct Answer: C
Rationale: Damage to the stomach can lead to a reduced ability to produce gastric acid (Choice C) and intrinsic factor, the latter of which is crucial for vitamin B12 absorption (Choice D). That's why these two choices are correct. The stomach doesn't play a direct role in the digestion of carbohydrates (Choice A) as this process primarily occurs in the small intestine with the help of pancreatic enzymes. Similarly, bile is produced by the liver and stored in the gallbladder, not the stomach, hence stomach damage wouldn't lead to an inability to produce or secrete bile (Choice B).