Which of the following substances is responsible for donating H+ ions to act as a buffer when blood pH rises?
Carbon dioxide.
Carbon monoxide.
Carbonic acid.
Oxygen.
The Correct Answer is C
In the human body, maintaining the pH of the blood within a narrow range is critical for proper physiological functioning.
One of the buffering systems that helps to regulate blood pH involves the conversion of carbon dioxide (CO2) and water (H2O) into carbonic acid (H2CO3), which then dissociates into hydrogen ions (H+) and bicarbonate ions (HCO3-).
Carbonic acid (H2CO3) is responsible for donating H+ ions to act as a buffer when blood pH rises.
When blood pH rises (becomes more alkaline), carbonic acid dissociates, and the H+ ions combine with bicarbonate ions to form more carbonic acid.
This helps to remove excess H+ ions from the blood and prevent the pH from rising too much.
Option A, carbon dioxide, is involved in the buffering system through its conversion to carbonic acid.
However, it does not directly donate H+ ions to act as a buffer when blood pH rises.
Option B, carbon monoxide, is a toxic gas that binds to hemoglobin in red blood cells, preventing them from carrying oxygen.
It is not involved in the buffering system and does not donate H+ ions.
Option D, oxygen, is carried by hemoglobin in red blood cells and is essential for respiration.
It is not involved in the buffering system and does not donate H+ ions.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is C
Explanation
The two major parts of the nervous system are the Central Nervous System (CNS) and the Peripheral Nervous System (PNS).
The CNS comprises the brain and spinal cord and acts as the integration and command centre of the body.
The PNS represents the conduit between the CNS and the body and is further subdivided into the somatic nervous system (SNS) and the autonomic nervous system (ANS).
Choice A is incorrect because it only mentions two subdivisions of the PNS: the autonomic nervous system (ANS) and the somatic nervous system (SNS).
Choice B is incorrect because it only mentions one major part of the nervous system, the PNS, and one subdivision of it, the SNS.
Choice D is incorrect because it only mentions one major part of the nervous system, the CNS, and one subdivision of the PNS, the ANS.
Correct Answer is B
Explanation
The correct answer is choice B. 3’ TCGATCGCA 5’.
In DNA, the nitrogenous bases adenine (A) and thymine (T) pair together, while cytosine © and guanine (G) pair together.
Therefore, the complementary strand of the given DNA sequence “5’ AGCTAGCGT 3’” would have the nitrogenous bases T, C, G, A, T, C, G, C and A in that order.
Additionally, the 5’ to 3’ direction of the complementary strand is opposite to that of the given strand.
Choice A. 3’ AGCTAGCGT 5’ is not correct because it is not complementary to the given strand.
Choice C. 5’ UCGAUCGCA 3’ is not correct because it contains uracil (U), which is a nitrogenous base found in RNA, not DNA.
Choice D. 3’ TCGUTCGCU 3’ is not correct because it also contains uracil (U), which is a nitrogenous base found in RNA, not DNA.
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