Chapter 2: The Chemistry Of Life - PRACTICE QUESTIONS

Which of these factors will cause an increase in the rate of reaction?

a) presence of an enzyme b) lower reactant concentration c) absence of a catalyst d) decrease in temperature Correct Answer: A

The alpha-helix and beta-pleated sheet are characteristic of:

a) primary protein structure. b) secondary protein structure. c) tertiary protein structure. d) quaternary protein structure. Correct Answer: B

Positively charged subatomic particles are called __________.

a) protons b) neutrons c) nuclei d) electrons Correct Answer: A

Which parts of atoms can interact (react) to form chemical bonds?

a) protons b) the nucleus of each atom c) the orbitals d) valence electrons Correct Answer: D

Salts are held together by:

a) single covalent bonds b) ionic bonds c) polar covalent bonds d) nonpolar covalent bonds Correct Answer: B

Electrolytes are charged particles called ions that are dissolved in body fluids. Which of the following ions would be considered a major anion in the body?

a) sodium b) potassium c) calcium d) chloride Correct Answer: D

Which of the following statements is accurate?

a) A compound consisting of two identical nonmetals is hydrophilic b) A compound made of a metal and nonmetal is hydrophobic c) A compound made of a metal and a nonmetal is hydrophilic d) A compound made only of carbon and hydrogen is hydrophilic Correct Answer: C

What is the function of a buffer system?

a) Buffer systems lower the activation energy of a chemical reaction. b) Buffer systems prevent large swings in pH when an acid or base is added to a solution. c) Buffer systems absorb heat without changing the temperature themselves. d) Buffer systems act as a lubricant between two adjacent surfaces. Correct Answer: B

Which statement best describes enzyme function?

a) Enzymes can perform catabolic reactions only. b) One enzyme can work on thousands of different substrates. c) Enzymes speed chemical reactions by lowering the activation energy. d) Enzymes chemically alter both the reactants and products. Correct Answer: C

Na+ is best known as a(n):

a) Ion b) Macromolecule c) Compound d) Molecule Correct Answer: A

What happens in oxidation-reduction (redox) reactions?

a) Larger molecules are built from smaller subunits. b) Atoms are exchanged. c) Electron exchange occurs. d) Energy is used since these are endergonic reactions. Submit Correct Answer: C

Blood is a mixture of fluid and insoluble particles that are large enough to be visible, such as blood cells and platelets. Therefore, blood is a __________.

a) Solution b) Solvent c) Colloid d) Suspension Correct Answer: D

Enzymes bind with substrates at their active sites and are permanently altered by the binding process.

a) True b) False Correct Answer: B

Foods are broken down into their building blocks by adding water. This would be an example of which characteristic of water?

a) Water acts as a lubricant. b) Water has a high heat of vaporization. c) Water acts as a cushion. d) Water acts as a reactant. Correct Answer: D

Water acts to dissolve molecules in the body. How does water dissolve the salt (NaCl) in your mouth from a salty pretzel?

a) When water is added to the NaCl, NaCl is broken down by adding OH- to one element and H+ to the other. This is known as hydrolysis. b) Water acts as a cofactor for enzymes that dissolve the salt. c) Water acts as a solvent because the partial negative charge on the oxygen in the water attracts sodium, while the partial positive charge on hydrogen attracts chloride. This results in the separation of sodium from chloride, thus breaking the ionic bond. Correct Answer: C

Atoms of oxygen have a total of 8 electrons. Are these atoms stable, and why or why not?

a) Yes, because the Octet Rule says stable atoms have 8 electrons. b) Yes, because oxygen is in the air we breathe and it doesn't hurt us. c) No, because only atoms with 2 valence electrons are stable. d) No, because the atoms have only 6 valence electrons, but need 8 for stability. Correct Answer: D

Carbon atoms have four valence electrons. Are they likely to react with other atoms, and why or why not?

a) Yes, but only with other stable atoms. b) Yes, because they can become more stable by doing so. c) No, because they have an even number of valence electrons so they are already stable. d) No, because they do not have enough valence electrons. Correct Answer: B

In plasma, a typical body fluid, protein floating around would be considered to be which of the following?

a) a solute, specifically both a colloid and a nonelectrolyte b) a solute, specifically both a colloid and an electrolyte c) a solvent Submit Correct Answer: B

This is an example of __________.

a) an ionic bond b) a polar covalent bond c) a nonpolar covalent bond d) a hydrogen bond Correct Answer: A

Which of the following is not produced through chemical bonding?

a) atoms b) cells c) adipose (fat) tissue d) the heart Correct Answer: A

Prions are infectious particles that can cause normal proteins to assume a misfolded shape. When the proteins assume an abnormal three-dimensional shape, they:

a) become enzymes b) become unstable c) lose their primary structure d) lose their function Correct Answer: D

What type of compound is NOT likely to dissolve in water?

a) both polar and nonpolar covalent compounds b) ionic compound c) polar covalent compound d) nonpolar covalent compound Correct Answer: D

What is the building block of a lipid?

a) glucose b) nucleic acid c) fatty acid d) glycogen Correct Answer: C

Amino acids are the monomers for:

a) lipids b) proteins c) carbohydrates d) nucleic acids Correct Answer: B

The four most common elements, comprising 96% of the body's mass, are:

a) oxygen, nitrogen, hydrogen, carbon. b) oxygen, potassium, iron, copper. c) carbon, sodium, phosphorus, sulfur. d) chlorine, sodium, magnesium, potassium. Submit Correct Answer: A

A substance that always donates hydrogen ions to a solution is called __________.

a) pH b) a buffer c) a base d) an acid Correct Answer: D

Which pH is more acidic, a pH of 3, a pH of 7, or a pH of 9?

a) pH of 9 b) pH of 7 c) pH of 3 Correct Answer: C

Cortisol is a type of lipid hormone. Which type of lipid would cortisol be classified as?

a) phospholipid b) triglyceride c) steroid Correct Answer: C

Ionic bonds result from:

a) the unequal sharing of electrons between nonmetal atoms. b) the equal sharing of electrons between nonmetal atoms. c) the transfer of electrons from a metal atom to a nonmetal atom. d) weak attractions between polar molecules. Submit Correct Answer: C