Question 1

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

Accepted Answer

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

Question 2

A sodium atom ($$\mathrm{Na}) $$has an atomic number of 11 and a mass number of 23. How many neutrons does it have?

Accepted Answer

$$23 - 11 = 12$$ neutrons

Question 3

Which of the following statements about covalent bonds is TRUE?

Accepted Answer

Covalent bonds involve the sharing of electron pairs between atoms.

Question 4

A molecule of water ($$\mathrm{H_2O}) is $$held together by which type of bond between its atoms, and which type of bond between different water molecules?

Accepted Answer

Covalent bonds within the molecule; hydrogen bonds between molecules

Question 5

Which of the following best explains why phospholipids are important components of cell membranes?

Accepted Answer

They are amphipathic, having both polar heads and nonpolar tails, allowing them to form bilayers.

Question 6

A solution has a pH of 5. Which of the following statements is correct?

Accepted Answer

The solution is acidic and has more $$\mathrm{H^+}$$ ions than $$\mathrm{OH^-}$$ ions.

Question 7

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

Accepted Answer

The breakdown of glucose during cellular respiration to release energy.

Question 8

Which property of water is most important for its role as a lubricant in the human body?

Accepted Answer

Its ability to reduce friction between surfaces.

Question 9

Which of the following best describes the difference between organic and inorganic compounds?

Accepted Answer

Organic compounds always contain carbon and hydrogen and usually have covalent bonds.

Question 10

A patient’s blood pH is measured at 7.2. Which of the following best describes this condition?

Accepted Answer

The blood is acidic and has excess $$\mathrm{H^+}$$ ions.

Question 11

Which of the following is a polysaccharide stored in the human body?

Accepted Answer

Glycogen

Question 12

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

Accepted Answer

One glycerol molecule bonded to three fatty acids

Question 13

Steroids are characterized by which structural feature?

Accepted Answer

Four rings of carbon atoms

Question 14

Which level of protein structure is primarily responsible for the overall 3D shape of a single polypeptide chain?

Accepted Answer

Tertiary structure

Question 15

Enzymes speed up chemical reactions in the body by:

Accepted Answer

Lowering the activation energy required for the reaction

Question 16

Which of the following is TRUE about hydrogen bonds?

Accepted Answer

They are weak bonds that help determine the three-dimensional structure of proteins and DNA.

Question 17

Which of the following is a correct example of an ionic bond formation?

Accepted Answer

Sodium ($$\mathrm{Na}) $$donates an electron to chlorine ($$\mathrm{Cl}$$), forming $$\mathrm{Na^+}$$ and $$\mathrm{Cl^-}$$ ions.

Question 18

Which of the following best describes the role of buffers in the human body?

Accepted Answer

Buffers help maintain a stable pH by neutralizing excess acids or bases.

Question 19

Which of the following is a correct formula for calculating the pH of a solution?

Accepted Answer

$$\mathrm{pH} = -\log_{10}[\mathrm{H^+}]$$

Chapter 2: The Chemical Level of Organization – Study Notes for Anatomy & Physiology

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