Nokea
Which of the following statements is false?
- A. Hemoglobin functions as a buffer
- B. Bicarbonate ions tend to diffuse out of red blood cells into the blood plasma.
- C. The movement of molecules is in different directions in the metabolically active tissues and the alveoli.
- D. Carbonic anhydrase is an enzyme that promotes the formation of oxyhemoglobin.
Correct Answer: D
Rationale: The correct answer is D because carbonic anhydrase catalyzes the conversion of carbon dioxide and water into bicarbonate ions and protons, not the formation of oxyhemoglobin. Step-by-step rationale: 1. Hemoglobin functions as a buffer by binding to hydrogen ions to help regulate pH levels in the blood. 2. Bicarbonate ions do tend to diffuse out of red blood cells into the plasma to maintain the balance of CO2 and pH. 3. The movement of molecules is indeed different in metabolically active tissues (where oxygen is released and CO2 is taken up) compared to the alveoli (where the opposite occurs). Therefore, choices A, B, and C are all correct statements, making D the false statement.
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During transportation of Carbon dioxide, blood will not become acidic, because
- A. It contains hemoglobin
- B. It contains Hemoglobinc acid
- C. It contains Buffers
- D. It contains high CO2
Correct Answer: C
Rationale: Rationale: Choice C is correct because blood contains buffers like bicarbonate that help maintain pH balance by neutralizing excess acids or bases. This prevents blood from becoming acidic during CO2 transportation. Choices A and B are incorrect as hemoglobin doesn't directly regulate blood pH, and hemoglobinc acid is not a component in blood. Choice D is incorrect as high CO2 levels can actually lead to blood becoming more acidic if not properly buffered.
Fick's law of diffusion is related to
- A. Diffusion and Surface area
- B. Diffusion and membrane potential
- C. Diffusion and water content
- D. Diffusion and pore diameter
Correct Answer: A
Rationale: Fick's law of diffusion states that the rate of diffusion is directly proportional to the surface area and concentration gradient, and inversely proportional to the distance over which diffusion occurs. Therefore, Choice A - Diffusion and Surface area is correct because surface area directly affects the rate of diffusion. Choices B, C, and D are incorrect as they do not directly relate to Fick's law. B is incorrect as membrane potential is not a factor in Fick's law. C is incorrect as water content is not a key factor in the law of diffusion. D is incorrect as pore diameter is not explicitly mentioned in Fick's law.
The last mammalian structure that air moves through before the alveoli is the
- A. larynx.
- B. glottis.
- C. bronchioles.
- D. trachea.
Correct Answer: C
Rationale: The correct answer is C: bronchioles. After air passes through the trachea, it enters the bronchi, which further divide into bronchioles. The bronchioles are the last structures where air passes before reaching the alveoli for gas exchange. The larynx is involved in sound production and the glottis is the opening between the vocal cords in the larynx. While the trachea is the initial passage for air into the respiratory system, the bronchioles are the final branching structures where air reaches the alveoli, making them the correct answer.
The organ of the respiratory system that traps bacteria with a ring of tonsils is the:
- A. nose
- B. pharynx
- C. larynx
- D. trachea
Correct Answer: B
Rationale: The correct answer is B: pharynx. The pharynx is the organ that traps bacteria with its tonsils. The tonsils are located in the pharynx and act as the body's first line of defense against pathogens entering the respiratory system. The nose (choice A) is responsible for warming, humidifying, and filtering air, but it does not trap bacteria with tonsils. The larynx (choice C) is involved in sound production and preventing food from entering the airway, not trapping bacteria. The trachea (choice D) is the windpipe that carries air to and from the lungs, but it does not have tonsils to trap bacteria.
The partial pressure of carbon dioxide in venous blood is approximately
- A. 40 mm Hg
- B. 45 mm Hg
- C. 50 mm Hg
- D. 70 mm Hg
Correct Answer: B
Rationale: The correct answer is B (45 mm Hg) because the partial pressure of carbon dioxide in venous blood is typically around 40-45 mm Hg. This value represents the amount of CO2 dissolved in the blood plasma. Option A (40 mm Hg) is slightly on the lower side and may not fully reflect the average value. Option C (50 mm Hg) is higher than the usual range for venous blood CO2 levels. Option D (70 mm Hg) is significantly higher than the normal range and is more characteristic of arterial blood CO2 levels. Therefore, option B is the most accurate representation of the partial pressure of CO2 in venous blood.