Q: A solution has a pH of 5. What is the concentration of hydrogen ions $$[H^+] in $$this solution?

$$[H^+] = 1 \times 10$$^{-5}$$ \ \mathrm{mol/L}$$

Question 1

Which of the following best describes the difference between a molecule and a compound?

Accepted Answer

A molecule consists of two or more atoms of the same element, while a compound consists of two or more atoms of different elements.

Question 2

A patient is diagnosed with an electrolyte imbalance. Which of the following ions, if out of balance, would most directly affect nerve impulse transmission?

Accepted Answer

Potassium (K^+)

Question 3

Which of the following statements about isotopes is correct?

Accepted Answer

Isotopes have the same number of protons but different numbers of neutrons.

Question 4

A solution has a pH of 5. What is the concentration of hydrogen ions $$[H^+] in $$this solution?

Accepted Answer

$$[H^+] = 1 	imes 10$$^{-5}$$ \ \mathrm{mol/L}$$

Question 5

Which of the following best explains why water is considered a polar molecule?

Accepted Answer

It has a partial positive charge on the hydrogen atoms and a partial negative charge on the oxygen atom.

Question 6

A protein is exposed to high heat and loses its function. What is the most likely explanation for this loss of function?

Accepted Answer

The protein is denatured, losing its tertiary and possibly secondary structure.

Question 7

Which of the following best describes the role of enzymes in chemical reactions?

Accepted Answer

Enzymes lower the activation energy, speeding up the reaction.

Question 8

A dehydration synthesis reaction between two monosaccharides results in which of the following?

Accepted Answer

A disaccharide and a molecule of water are produced.

Question 9

Which of the following is a correct example of a reversible reaction in the human body?

Accepted Answer

$$\mathrm{CO}_2 + \mathrm{H}_2\mathrm{O} \rightleftharpoons \mathrm{H}_2\mathrm{CO}_3$$

Question 10

A patient is suffering from acidosis. Which of the following would be an appropriate physiological response to help restore homeostasis?

Accepted Answer

Increase the concentration of sodium bicarbonate (a buffer) in the blood.

Question 11

Which of the following best describes the structure of a phospholipid?

Accepted Answer

A diglyceride attached to a phosphate group and two fatty acid tails.

Question 12

Which of the following statements about ATP is correct?

Accepted Answer

ATP stores energy in the bonds between its phosphate groups.

Question 13

Which of the following is a function of cholesterol in the human body?

Accepted Answer

It is a component of plasma (cell) membranes.

Question 14

A solution is described as hydrophobic. Which of the following substances is most likely to be found in this solution?

Accepted Answer

Triglyceride (fat)

Question 15

Which of the following best explains why proteins are sensitive to changes in pH?

Accepted Answer

Changes in pH can disrupt hydrogen bonds, altering protein shape and function.

Question 16

Which of the following is a correct pairing of a nitrogenous base in DNA?

Accepted Answer

Cytosine (C) pairs with guanine (G)

Question 17

A patient is given an intravenous solution containing a high concentration of sodium chloride. What effect might this have on the patient's cells?

Accepted Answer

Cells will shrink due to water moving out of them.

Question 18

Which of the following best describes the difference between saturated and unsaturated fatty acids?

Accepted Answer

Saturated fatty acids have no double bonds; unsaturated fatty acids have one or more double bonds.

Question 19

Which of the following best explains why enzymes are specific to their substrates?

Accepted Answer

The active site of an enzyme has a unique shape that fits only specific substrates.

The Chemical Level of Organization: Atoms and Elements in Human Physiology

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