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Which of the following substances is responsible for donating H+ ions to act as a buffer when blood pH rises?  

A. Carbon dioxide

B. Carbon monoxide

C. Carbonic acid

D. Oxygen

Answer Explanation:

Carbonic acid.

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.

Therefore, the Correct Answer is C.

More Questions on TEAS 7 Science

  • Q #1: Which of the following structures in the female reproductive system secretes hormones to maintain the uterine lining during pregnancy?

    A. Umbilical cord

    B. Corpus luteum

    C. Oviduct

    D. Oocyte

    Answer Explanation

    The corpus luteum is a structure that develops in the ovary after an egg has been released.

    It secretes the hormone progesterone, which prepares the uterus for a fertilized egg to implant and helps maintain the uterine lining during pregnancy1.

     

     

    Choice A.

    Umbilical cord is not correct because it is a structure that connects the developing fetus to the placenta and provides nutrients and oxygen to the fetus, but does not secrete hormones.

    Choice C.

    Oviduct is not correct because it is a tube that transports eggs from the ovary to the uterus, but does not secrete hormones.

    Choice D.

    Oocyte is not correct because it is an immature egg cell, but does not secrete hormones.

     

  • Q #2: Which of the following is the function of a totipotent cell?  

    A. Fights infectious diseases.

    B. Aids in the maturation of sex cells.

    C. Carries electrical impulses.

    D. Develops into any kind of cell.

    Answer Explanation

    A totipotent cell can self-renew by dividing and develop into the three primary germ cell layers of the early embryo and into extra-embryonic tissues such as the placenta.

    A fertilized egg is a totipotent stem cell and as such can develop into any specialized cell found in the organism.

    Choice A is not correct because totipotent cells do not fight infectious diseases.

    Choice B is not correct because totipotent cells do not aid in the maturation of sex cells.

    Choice C is not correct because totipotent cells do not carry electrical impulses.

     

  • Q #3: Which of the following is a group that can be measured against the experimental group?

    A. Responding

    B. Manipulated

    C. Control

    D. Variable

    Answer Explanation

    Control.

    A control group is a group in an experiment that does not receive the treatment or manipulation being tested and is used as a benchmark to measure how the other tested subjects do.

    The control group is used to minimize the effects of all variables except the independent variable.

    This allows researchers to determine if changes in the dependent variable are due to the manipulation of the independent variable or if they are due to some other factor.

    Choice A.

    Responding is not the correct answer because it refers to the dependent variable, which is the variable that is being measured in an experiment.

    Choice B.

    Manipulated is not the correct answer because it refers to the independent variable, which is the variable that is being manipulated in an experiment.

    Choice D.

    Variable is not the correct answer because it refers to any factor that can change in an experiment and can include both independent and dependent variables.