Nokea
Which metal ion is often present in the active site of carbonic anhydrase enzymes?
- A. Iron (Fe)
- B. Calcium (Ca)
- C. Zinc (Zn)
- D. Magnesium (Mg)
Correct Answer: C
Rationale: The correct answer is C: Zinc (Zn). Zinc is often present in the active site of carbonic anhydrase enzymes because it plays a crucial role in catalyzing the conversion of carbon dioxide to bicarbonate and protons. Zinc ions have the appropriate coordination geometry and charge to facilitate this reaction efficiently. Iron (Fe) is not typically found in the active site of carbonic anhydrase enzymes. Calcium (Ca) and Magnesium (Mg) do not have the appropriate properties to serve as the catalytic metal ion in this enzyme. Therefore, zinc (Zn) is the correct answer due to its specific role and properties in the catalytic mechanism of carbonic anhydrase enzymes.
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The term "blue bloater" refers to which of the following conditions?
- A. Acute respiratory distress syndrome (ARDS)
- B. Asthma
- C. Chronic obstructive bronchitis
- D. Emphysema
Correct Answer: C
Rationale: The correct answer is C: Chronic obstructive bronchitis. The term "blue bloater" is a classic descriptor used in the context of chronic obstructive bronchitis. It refers to patients who exhibit cyanosis (blue discoloration of the skin due to lack of oxygen) and are often overweight and edematous. This term is used to differentiate from "pink puffers" who have emphysema. Both conditions are part of chronic obstructive pulmonary disease (COPD), but the "blue bloater" presentation is more characteristic of chronic bronchitis due to the chronic hypoxia and retained carbon dioxide.
Now, let's evaluate why the other choices are incorrect:
A: Acute respiratory distress syndrome (ARDS) typically presents with severe difficulty breathing and rapid onset of respiratory failure. It is not referred to as a "blue bloater."
B: Asthma is characterized by reversible airway obstruction and wheezing, usually triggered by allergens or irrit
A nurse has educated a client on isoniazid. What statement by the client indicates that teaching has been effective?
- A. I need to take extra vitamin C while on isoniazid.
- B. I should take this medicine with milk or juice.
- C. I will take this medication on an empty stomach.
- D. My contact lenses will be permanently stained.
Correct Answer: C
Rationale: The correct answer is C: "I will take this medication on an empty stomach." This indicates effective teaching because isoniazid should be taken on an empty stomach to maximize absorption. Taking it with food can reduce absorption.
A: Taking extra vitamin C is not necessary for isoniazid.
B: Taking isoniazid with milk or juice can reduce its effectiveness.
D: Contact lenses are not affected by isoniazid, so they will not be permanently stained.
Wall of Larynx is supported by the cartilage
- A. Cricoid
- B. Thyroid
- C. Artynoid
- D. All these
Correct Answer: D
Rationale: The correct answer is D, All these. The wall of the larynx is supported by a combination of cartilages, including the cricoid, thyroid, and arytenoid cartilages. The cricoid cartilage forms the base of the larynx, the thyroid cartilage forms the front and sides, and the arytenoid cartilages sit on top of the cricoid and are involved in vocal cord movement. Each of these cartilages plays a crucial role in supporting and maintaining the structure and function of the larynx. Therefore, all of these cartilages collectively support the wall of the larynx. Choices A, B, and C are incorrect because each of these cartilages individually contributes to the support of the larynx, but it is the combination of all three that fully supports the wall of the larynx.
Respiratory mechanism is controlled by
- A. Central nervous system
- B. Sympathetic nervous system
- C. Parasympathetic nervous system
- D. Autonomic nervous system
Correct Answer: A
Rationale: The correct answer is A: Central nervous system. The respiratory mechanism is controlled by the brainstem, specifically the medulla oblongata and pons. These areas of the central nervous system regulate breathing by monitoring levels of carbon dioxide and oxygen in the blood. The medulla sets the basic rhythm of breathing, while the pons helps fine-tune the breathing rate. Choices B, C, and D are incorrect because while the sympathetic and parasympathetic nervous systems are involved in regulating various bodily functions, they do not directly control the respiratory mechanism. The autonomic nervous system, which includes both the sympathetic and parasympathetic divisions, plays a role in involuntary functions like heart rate and digestion, but it is not the primary controller of breathing.
Carbon monoxide
- A. has a very low affinity or attraction to hemoglobin.
- B. is unlikely to be transported by the circulatory system.
- C. is not the cause of death of people who breathe excessive amounts of automobile exhausts.
- D. can arise from cigarette smoke
Correct Answer: D
Rationale: The correct answer is D because carbon monoxide can indeed arise from cigarette smoke due to incomplete combustion of tobacco. This is supported by scientific evidence. Carbon monoxide has a high affinity for hemoglobin, so choice A is incorrect. It can be transported by the circulatory system, making choice B incorrect. Breathing excessive amounts of automobile exhaust containing carbon monoxide can lead to death, making choice C incorrect.