What is the function of villi and microvilli in the GI tract?
- A. produce bile
- B. kill bacteria
- C. produce vitamin K
- D. increase the surface area for absorption
Correct Answer: D
Rationale: Villi and microvilli in the GI tract serve to increase the surface area of the small intestine, aiding in the absorption of nutrients into the bloodstream. Choices A, B, and C are incorrect as villi and microvilli are primarily involved in enhancing absorption, not in producing bile, killing bacteria, or producing vitamin K.
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In PEM, which condition is characterized by symptoms such as muscle weakness, hanging skin, delayed tooth eruption, and changes in saliva?
- A. Marasmus
- B. Kwashiorkor
- C. Anemia
- D. Noma
Correct Answer: A
Rationale: The correct answer is Marasmus. Marasmus is a severe form of protein-energy malnutrition (PEM) that leads to muscle wasting, hanging skin, delayed growth, and changes in saliva. These symptoms are commonly seen in vulnerable populations such as children, homeless individuals, older adults, and substance abusers. Kwashiorkor, on the other hand, is characterized by edema, a distended belly, and skin lesions. Anemia is a condition characterized by a low red blood cell count, leading to fatigue and weakness. Noma is a severe infection affecting the face, particularly the mouth and jaw area.
Which enzyme digests fiber in the large intestine?
- A. salivary amylase
- B. pancreatic amylase
- C. cellulase
- D. none of the above
Correct Answer: D
Rationale: The correct answer is 'none of the above.' Human digestive enzymes like salivary amylase and pancreatic amylase cannot digest fiber. Instead, fiber is fermented by gut bacteria in the large intestine. Cellulase, which is an enzyme produced by some animals and microorganisms, can break down cellulose found in plants, but it is not a human digestive enzyme, making it an incorrect choice in this context.
What is considered an acceptable LDL cholesterol level for children and adolescents?
- A. Less than 70 mg/dL
- B. Less than 110 mg/dL
- C. Less than 129 mg/dL
- D. Less than 170 mg/dL
Correct Answer: B
Rationale: An LDL cholesterol level of less than 110 mg/dL is considered acceptable and healthy for children and adolescents. This level helps reduce the risk of cardiovascular diseases. Choices A, C, and D are incorrect because an LDL cholesterol level below 110 mg/dL is the recommended target for children and adolescents to maintain good heart health.
Sickle cell disease is an example of an inherited mistake in the amino acid sequence.
- A. TRUE
- B. FALSE
Correct Answer: A
Rationale: The statement is TRUE. Sickle cell disease is caused by a genetic mutation in the hemoglobin gene, leading to an abnormal amino acid sequence. This results in the production of abnormal hemoglobin molecules, causing red blood cells to become sickle-shaped. This inherited condition is a classic example of a genetic error affecting the amino acid sequence, making choice A the correct answer. Choices B, C, and D are incorrect as they do not accurately reflect the nature of sickle cell disease.
Muscle weakness due to wasting would most likely be evaluated by which test?
- A. recall of food intake
- B. skinfold thickness
- C. handgrip strength
- D. red blood cell levels
Correct Answer: C
Rationale: Handgrip strength is a reliable test to assess muscle function and detect muscle weakness due to wasting. It is often used to identify conditions like sarcopenia in clinical settings. Options A, B, and D are not suitable for evaluating muscle weakness. Food intake recall does not directly measure muscle function, skinfold thickness assesses body fat but not muscle strength, and red blood cell levels are unrelated to muscle wasting.