Chapter 2

Which of the following statements is incorrect? a. Isotopes have the same atomic number and different mass numbers. b. All molecules consist of atoms. c. Free radicals are dangerous because they emit energy.

Which element has only one proton? a. hydrogen b. an isotope c. helium d. a free radical

The mutual attraction of opposite charges holds atoms together as molecules in a(n) \(-\) bond. a. ionic b. hydrogen c. polar covalent d. nonpolar covalent

A salt does not release ___________ in water. a. ions b. \(\mathrm{H}^{+}\)

A(n)=$ _________ substance repels water. a. acidic b. basic c. hydrophobic d. polar

When dissolved in water, a(n) _______ donates \(\mathrm{H}^{+}\) and \(\mathrm{a}(\mathrm{n})\) ________ \(\text { accepts } \mathrm{H}^{+}\). a. acid; base b. base; acid c. buffer; solute d. base; buffer

Organic molecules consist mainly of __________ atoms. a. carbon b. carbon and oxygen c. carbon and hydrogen d. carbon and nitrogen

________________ is a simple sugar (a monosaccharide). a. Ribose b. Sucrose c. Starch d. all are monosaccharides

Unlike saturated fatty acids, the tails of unsaturated fatty acids incorporate one or more _________ .

Which of the following is a class of molecules that encompasses all of the other molecules listed? a. triglycerides b. fatty acids C. Waxes d. steroids e. lipids f. phospholipids

__________ are to proteins as ________ are to nucleic acids. a. Sugars; lipids b. Sugars; proteins c. Amino acids; hydrogen bonds d. Amino acids; nucleotides

A denatured protein has lost its _________ . a. hydrogen bonds b. shape c. function d. all of the above

Match the terms with their most suitable description. $$ \text {hydrophilic } \quad \quad \text {a. protons \(>\) electrons} $$ $$ \text {atomic number } \quad \quad \text {b. number of protons in nucleus} $$ $$ \text {hydrogen bonds } \quad \quad \text {c. polar; dissolves easily in water} $$ $$ \text {positive charge } \quad \quad \text {d. collectively strong} $$ $$ \text {negative charge} \quad \quad \text {e. protons \(<\) electrons} $$ $$ \text {temperature } \quad \quad \text {f. measure of molecular motion} $$ $$ \text {\(\mathrm{pH}\) } \quad \quad \text { g. decays} $$ $$ \text {covalent bond} \quad \quad \text {h. electron sharing} $$ $$ \text {radioisotope } \quad \quad \text {i. reflects \(\mathrm{H}^{+}\) concentration} $$

Match the molecules with the best description. $$ \text {WaX } \quad \quad \text {a. protein primary structure} $$ $$ \text {starch } \quad \quad \text {b. an energy carrier} $$ $$ \text {triglyceride} \quad \quad \text {c. water-repellent secretions} $$ $$ \text {DNA } \quad \quad \text {d. richest energy source} $$ $$ \text {polypeptide} \quad \quad \text {e. sugar storage in plants} $$ $$ \text {\(\mathrm{ATP}\) } \quad \quad \text {f. sugar storage in animals and fungi} $$ $$ \text {glycogen} \quad \quad \text { g. carries heritable information} $$

Match the molecules with the best description. $$ \text {protein } \quad \quad \text {a. phosphate, fatty acids} $$ $$ \text {phospholipid } \quad \quad \text {b. amino acids, sugar(s)} $$ $$ \text {glycoprotein} \quad \quad \text {c. glycerol, fatty acids} $$ $$ \text {fat } \quad \quad \text {d. nucleotides} $$ $$ \text {nucleic acid} \quad \quad \text {e. glucose onlys} $$ $$ \text {cellulose } \quad \quad \text {f. sugar, phosphate, base} $$ $$ \text {nucleotide} \quad \quad \text { g. amino acids} $$ $$ \text {Sucrose} \quad \quad \text {h. glucose, fructose} $$