/

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

A. Carbon dioxide

B. Carbonic acid

C. Oxygen

D. Carbon monoxide

Answer Explanation:

A buffer is a solution that can resist changes in pH when small amounts of acid or base are added. In the human body, blood is an important buffer that helps maintain a stable pH of about 7.4. One of the main components of the blood buffer system is the bicarbonate buffer, which involves the equilibrium between carbon dioxide (CO2), carbonic acid (H2CO3), and bicarbonate ions (HCO3-). When blood pH rises, meaning it becomes more basic, the bicarbonate buffer can donate H+ ions to lower the pH and restore the balance. The substance that donates H+ ions in this case is carbonic acid, which dissociates into H+ and HCO3-. Therefore, 

 

Therefore, the Correct Answer is B.

More Questions on TEAS 7 Science

  • Q #1: Which of the following organic molecules contain both an amine and carboxyl group?

    A. Lipids

    B. Proteins

    C. Chitin

    D. Cellulose

    Answer Explanation

    An amine group is a nitrogen atom bonded to three hydrogen atoms, and a carboxyl group is a carbon atom double-bonded to an oxygen atom and single-bonded to a hydroxyl group. These groups are important for the formation of amino acids, which are the building blocks of proteins.

  • Q #2: Which of the following allows the AIDS virus, which contains RNA, to insert viral DNA into the DNA of a host T-cell after the AIDS virus enters the cell?

    A. Reverse transcriptase, an enzyme encoded by the virus.

    B. Receptor proteins located on the surface of the virus.

    C. The phospholipids found on the envelope of the virus.

    D. The protein that makes up the capsid of the virus.

    Answer Explanation

    Reverse transcriptase, an enzyme encoded by the virus. This enzyme can convert the viral RNA into DNA, which can then integrate into the host cell's genome and hijack its machinery to produce more viruses. The other options are not relevant to this process. Receptor proteins are involved in binding the virus to the cell membrane, but they do not insert viral DNA into the cell. The phospholipids and the protein capsid are structural components of the virus, but they do not have any enzymatic activity.

  • Q #3: Osteoporosis results from which of the following?

    A. An increase in osteocyte activity while osteoclast activity continues at expected levels

    B. A decline in osteoblast activity while osteoclast activity continues at expected levels

    C. An increase in osteocyte activity while osteoblast activity continues at expected levels

    D. A decline in osteoclast activity while osteoblast activity continues at expected levels

    Answer Explanation

     

    Osteoporosis is a condition that affects the bones, making them weak and brittle. It occurs when the balance between bone formation and bone resorption is disrupted. Bone formation is carried out by cells called osteoblasts, while bone resorption is done by cells called osteoclasts. Osteocytes are mature bone cells that maintain the bone matrix. Osteoporosis results from a decline in osteoblast activity while osteoclast activity continues at expected levels, leading to more bone loss than bone gain. This reduces the bone density and increases the risk of fractures.