Q: A solution has a pH of 4. What is the concentration of hydrogen ions ($$[H^+]) in $$this solution?

$$[H^+] = 1 \times 10$$^{-4}$$ \ \mathrm{mol/L}$$

Question 1

Which of the following best explains why water is considered the 'universal solvent' in biological systems?

Accepted Answer

Because water's polarity allows it to dissolve most polar molecules and ions by forming hydration shells around them.

Question 2

A patient is admitted to the hospital with a blood pH of 7.0. Which physiological response would help restore homeostasis?

Accepted Answer

The buffer system would accept H+ ions, raising the pH toward normal.

Question 3

Which of the following statements about isotopes is correct?

Accepted Answer

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

Question 4

A solution has a pH of 4. What is the concentration of hydrogen ions ($$[H^+]) in $$this solution?

Accepted Answer

$$[H^+] = 1 	imes 10$$^{-4}$$ \ \mathrm{mol/L}$$

Question 5

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

Accepted Answer

A molecule is made of two or more atoms held together by chemical bonds, while a compound is a molecule that contains at least two different elements.

Question 6

Which of the following is a correct example of a dehydration synthesis reaction?

Accepted Answer

Forming a peptide bond between two amino acids with the release of a water molecule.

Question 7

Which of the following best explains why saturated fatty acids are solid at room temperature while unsaturated fatty acids are liquid?

Accepted Answer

Saturated fatty acids have straight chains that pack closely together, while unsaturated fatty acids have kinks due to double bonds that prevent tight packing.

Question 8

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

Accepted Answer

The protein underwent denaturation, losing its three-dimensional shape.

Question 9

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

Accepted Answer

Enzymes act as catalysts, lowering the activation energy and speeding up reactions.

Question 10

Which of the following pairs is correctly matched regarding nucleic acids?

Accepted Answer

DNA contains deoxyribose sugar and thymine.

Question 11

A patient is found to have a blood pH of 6.5. Which buffer system reaction would help restore normal pH?

Accepted Answer

$$\mathrm{$$HCO_3$$^-} ($$bicarbonate) accepts H+ to form $$\mathrm{H_2CO_3} ($$carbonic acid).

Question 12

Which of the following best describes the relationship between the atomic number and the mass number of an atom?

Accepted Answer

Atomic number is the number of protons; mass number is the sum of protons and neutrons.

Question 13

Which of the following is true regarding the structure of DNA?

Accepted Answer

DNA is double-stranded and contains thymine.

Question 14

Which of the following best explains why nonpolar molecules such as oil do not dissolve in water?

Accepted Answer

Nonpolar molecules are excluded by water due to hydrophobic exclusion and cannot form hydrogen bonds with water.

Question 15

Which of the following is a correct statement about the pH scale?

Accepted Answer

A solution with pH 2 is 100 times more acidic than a solution with pH 4.

Question 16

Which of the following best describes the difference between ionic and covalent bonds?

Accepted Answer

Ionic bonds involve the transfer of electrons from one atom to another, resulting in oppositely charged ions, while covalent bonds involve the sharing of electrons between atoms.

Question 17

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

Accepted Answer

Energy storage, insulation, and protection

Question 18

Which of the following best describes the primary structure of a protein?

Accepted Answer

The sequence of amino acids in the polypeptide chain.

Question 19

Which of the following is true regarding the formation of ATP in cells?

Accepted Answer

ATP is formed from ADP and phosphate ($$\mathrm{P}) $$during anabolic reactions, requiring energy input.

The Chemical Level of Organization: Study Notes for Anatomy & Physiology

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