MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) The smallest stable units of matter are
1) _______
A) molecules.
B) neutrons.
C) atoms.
D) electrons.
E) protons.
2) The "atomic number" of an atom is determined by the number of ________ it has.
A) protons + neutrons
B) electrons
C) protons + electrons
D) protons
E) neutrons

2) _______

3) The "atomic weight" of an atom reflects the average number of
A) electrons.
B) protons.
C) protons + neutrons + electrons.
D) neutrons.
E) protons + neutrons.

3) _______

4) One mole of any element
A) has the same number of electrons.
B) has the same mass.
C) has the same weight.
D) has the same number of atoms.


8) The innermost electron shell in an atom holds up to ________ electrons.

8) _______


A) 1

B) 2

C) 6

D) 8

E) 4

9) Radioisotopes have unstable
A) isotopes.
B) protons.
C) nuclei.
D) electron clouds.
E) ions.

9) _______

10) By weight, which element is the most plentiful in the human body?
A) sodium
B) sulfur
C) oxygen
D) potassium


14) Which element commonly has only a proton as its nucleus?
A) argon
B) hydrogen
C) carbon

14) ______
D) helium

E) neon

15) By weight, which element is the second most abundant in the human body?
A) calcium
B) oxygen
C) hydrogen
D) nitrogen
E) carbon

15) ______

16) The mass of an atom is largely determined by the number of ________ it has.
A) protons
B) electrons
C) neutrons
D) protons + neutrons

16) ______


E) protons + electrons

20) ______

A)
B)
C)
D)
E)

carbon monoxide.
carbonated oxygen.
carbonized oxygen.
carbon dioxide.
carbon oxide.

21) The molecule H2 is known as
A)
B)
C)
D)
E)

21) ______

helium.
hydrohydrogen.
hydrogen.
hydroxide.
semi-water.

22) When electrons are transferred from one atom to another, and the two atoms unite as a result of

25) The molecule O2 is known as
A) organic.

B) oxide.

25) ______
C) oxate

D) a salt

E) oxygen.

26) H2O is an example of a(n)
A) covalent formula.
B) ion.
C) glucose molecule.
D) compound.
E) ionic formula.
27) Which of the following is not a cation?
A) Ca2+
B) Na+

26) ______

27) ______
C) Cl-

D) K+

E) Mg2+

B) the number of protons.
C) the mass of the nucleus.
D) the size of the atom.
E) the number of neutrons.

31) ______

32) Ions with a + charge are called
A) cations.
B) isotopes.
C) radicals.
D) positrons.

32) ______


E) anions.
33) The weakest bond between two atoms is the ________ bond.
A) ionic
B) hydrogen
C) covalent
D) polar
E) nonpolar

33) ______

34) When atoms complete their outer electron shell by sharing electrons, they form
A) hydrogen bonds.
B) cations.
C) anions.

37) ______

38) Ions in an ionic molecule are held together due to
A) the presence of water molecules.
B) the sharing of electrons.
C) each electron orbiting all of the ions in the molecule.
D) the attraction of similar charges of the ions' protons.
E) the attraction of opposite electrical charges.

38) ______

39) An unequal sharing of electrons results in what type of chemical bonds?
A) hydrogen
B) ionic
C) covalent
D) polar covalent
E) peptide

39) ______

40) Sodium (Na) has an atomic number of 11. How many electrons are in the outer electron shell of

a

neutral


sodium
atom?


B)
C)
D)
E)

4 molecules, each containing a carbon atom and 4 hydrogen atoms
a molecule with 4 carbon atoms and 16 hydrogen atoms
an inorganic compound with ionic bonds
a molecule with 4 carbon atoms
4 molecules, each containing a carbon and a hydrogen atom

43) In an ionic bond, the electron donor is the ________, whereas the electron acceptor is the
________.
A) salt, ion
B) cation, anion
C) anion, cation
D) base, acid
E) acid, base

43) ______

44) In a molecule of nitrogen, three pairs of electrons are shared by two nitrogen atoms. The type of
bond that is formed is an example of a(n)
A) double divalent bond.
B) triple covalent bond.
C) single trivalent bond.
D) hydrogen bond.
E) polar covalent bond.

44) ______

48) The reaction N2 + 3 H2 → 2 NH3 is an example of a(n)
A)
B)
C)
D)
E)

48) ______

metabolic reaction.
decomposition reaction.
exchange reaction.
synthesis reaction.
enzyme reaction.

49) The reaction A + B + energy → AB is an example of a(n)
A) endergonic reaction.
B) exergonic reaction.
C) equilibrium reaction.
D) exchange reaction.
E) decomposition reaction.

49) ______

50) In hydrolysis reactions, compounds react with
A) glucose, causing decomposition.
B) hydrogen, causing decomposition.
C) water, causing decomposition.
D) water, causing synthesis.
E) carbon, causing decomposition.

C) 8

D) 2

E) 10

54) Chemical reactions that yield energy, such as heat, are said to be
A) exergonic.
B) thermonuclear.
C) neutral.
D) activated.
E) endergonic.

54) ______

55) All of the following are true concerning enzymes, except that they
A) function as biological catalysts.
B) lower the activation energy required for a reaction.
C) are consumed during the reaction.
D) affect only the rate of a chemical reaction.

55) ______


E) are proteins.
56) Compounds that can be synthesized or broken down by chemical reactions inside the body are
called
A) enzymes.
B) inorganic compounds.
C) nutrients.

60) During ionization, water molecules disrupt the ionic bonds of a salt to produce a mixture of ions.
These ions can carry a current and so are called
A) electrolytes.
B) acids.
C) anions.
D) counterions.
E) cations.

60) ______

61) Oppositely charged ions in solution are prevented from combining by
A) water's nonpolar nature.
B) hydration spheres.
C) hydrogen bonding.
D) free radicals.
E) heat capacity of water.

61) ______

62) An example of an inorganic substance is
A) water and carbon dioxide.
B) water.
C) carbon dioxide.
D) fructose.
E) glycerol.

62) ______

63) Hydrophilic molecules readily associate with
A) hydrophobic molecules.

D) pH 2

E) pH 10

66) ______

67) Which pH is closest to normal body pH?
A) pH 8
B) pH 4

E) pH 7

67) ______
C) pH 3

D) pH 2

68) A(n) ________ removes hydrogen ions and a(n) ________ releases hydrogen ions.
A) element; compound
B) molecule; acid
C) base; acid
D) compound; element
E) acid; base

68) ______

69) An excess of hydrogen ions in the body fluids can have fatal results because this can
A) change the shape of large complex molecules, rendering them nonfunctional.
B) change body fluid pH.
C) disrupt tissue functions.


71) ______

72) ______
D) a salt.

73) ______


A) pH 3

B) pH 2

C) pH 1

D) pH 6

E) pH 4

74) Which pH of the following is the least acidic?
A) pH 6
B) pH 4
C) pH 2

D) pH 3

E) pH 1

74) ______


B) A pH of 5 is greater.
C) They are both equal; 4 and 5 are relative values.
D) pH 9, if you mixed the solutions.
E) There is not enough information to determine.

78) ______

79) In the body, inorganic compounds
A) are structural components of cells.
B) can make up proteins.
C) can serve as buffers.
D) are metabolized for cellular energy.
E) are made from organic compounds.

79) ______

80) When placed in water, an inorganic compound dissociates 99 percent, forming hydrogen ions
and anions. This compound would be
A) a strong base.
B) a weak base.
C) a weak acid.
D) a salt.
E) a strong acid.

80) ______

81) When a small amount of HCl or NaOH is added to a solution of Na 2HPO4, the pH of the

81) ______


C) provide the same number of calories as an equivalent amount of sucrose.
D) are naturally similar to sugars.
E) are inorganic sugar substitutes.

84) ______

85) Fructose is
A) a carbohydrate.
B) a hexose.
C) found in male reproductive fluids.
D) an isomer of glucose.
E) All of the answers are correct.

85) ______

86) Molecules that have the same molecular formula but different structural formulas are called
A) isotopes.
B) isozymes.
C) isomoles.
D) isotypes.
E) isomers.

86) ______

87) The most important metabolic fuel molecule in the body is
A) protein.
B) sucrose.
C) glucose.

87) ______


90) ______

91) Carbohydrate molecules
A) form the regulatory molecules known as enzymes.
B) are composed of C, H, O, and N atoms.
C) contain the genetic information found in cells.
D) are the body's most readily available source of energy.
E) are the building blocks of cellular membranes.

91) ______

92) When two monosaccharides undergo a dehydration synthesis,
A) two new monosaccharides are formed.
B) a disaccharide is formed.
C) hydrolysis occurs.
D) a polysaccharide is formed.
E) a starch is formed.

92) ______

93) To bond two monomers together, a molecule of water must be ________ to/from from
monomers. This process is called ________.
A) added; hydrolysis
B) removed; crenation
C) added; denaturation
D) removed; dehydration synthesis
E) added; ionization

93) ______

97) Which of the following is/are needed to form a triglyceride molecule?
A) 3 glycerol molecules
B) 3 glycerol molecules and 3 fatty acid molecules
C) 3 fatty acid molecules and 1 glycerol molecule
D) 1 glycerol molecule
E) 3 fatty acid molecules

97) ______

98) A shortage of steroids in the body would result in a shortage of
A) proteins.
B) glycogen.
C) sex hormones and plasma membranes.
D) sex hormones.
E) plasma membranes.

98) ______

99) Most of the fat found in the human body is in the form of
A) cholesterol.
B) prostaglandins.
C) monoglycerides.
D) triglycerides.
E) phospholipids.

99) ______

100) Lipids that are produced by nearly every tissue in the body and act as local regulators are the
A) phospholipids.
B) glycolipids.


103) _____


104) The monomers of protein are
A) fatty acids.
B) nitrogen base.
C) glucose.
D) nucleotides.
E) amino acids.
105) Substrate molecules bind to enzymes at the ________ sites.
A) carboxyl
B) amino
C) neutral

104) _____

105) _____
D) reactant

E) active

106) You would expect a peptide bond to link
A) two simple sugars.
B) two nucleotides.
C) a sugar and a peptide.
D) two amino acids.
E) a peptide and a fatty acid.

106) _____

B) quaternary
C) pentanary
D) secondary
E) primary

110) _____

111) Interaction between individual polypeptide chains to form a protein complex is ________
structure.
A) quaternary
B) tertiary
C) pentagonal
D) secondary
E) primary

111) _____


112) Glycoproteins and proteoglycans are combinations of amino acids and
A) lipids.
B) inorganic compounds.
C) carbohydrates.
D) fatty acids.
E) nucleic acids.

112) _____

113) Which of the following is the symbol for an amino group?
A) -COOH
B) -OH

E) protein

116) _____

117) Molecules that store and process genetic information are the
A) lipids.
B) steroids.
C) nucleic acids.
D) carbohydrates.
E) proteins.

117) _____

118) An amino acid is to a protein as ________ is to a nucleic acid.
A) a purine
B) a nucleotide
C) a proton
D) a neutron
E) a protein

118) _____

119) A nucleotide consists of
A) a five-carbon sugar and a nitrogenous base.
B) a phosphate group and a nitrogenous base.
C) a five-carbon sugar, a nitrogenous base, and a phosphate group.
D) a five-carbon sugar and an amino acid.
E) a five-carbon sugar and phosphate group.

119) _____

123) The most abundant high-energy compound in cells is
A) DNA.
B) adenosine triphosphate.
C) adenosine monophosphate.
D) RNA.
E) adenosine diphosphate.

123) _____

124) A high-energy bond in ATP is present
A) between the first and second phosphate group.
B) between the second and third phosphate group.
C) between adenine and a phosphate group.
D) between adenine and ribose.
E) between phosphate groups 1 and 2 and between phosphate groups 2 and 3.

124) _____

125) The phosphorylation of adenosine forms
A) 2ATP.
B) ribose.
C) ATP.

125) _____
D) ADP.

E) AMP.

126) Identify the product formed from the phosphorylation of ADP.
A) adenosine diphosphate

A) disease.
B) surveillance.
C) specificity.
D) metabolic turnover.
E) surface tension.

129) _____

130) Continuous breakdown and replacement of cellular molecules is termed
A) metabolic turnover.
B) metabolism.
C) organic chemistry
D) anabolic turnover.
E) catabolic turnover.

130) _____

SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
131) A(n) ________ is a pure substance composed of atoms of only one kind.
131) ____________
132) The center of an atom is called the ________.

132) ____________

133) Electrons whirl around the center of the atom at high speed, forming a(n) ________.

133) ____________

134) Electrons in an atom occupy an orderly series of electron shells or ________.


141) ____________

142) Chemical reactions that absorb energy are called ________.

142) ____________

143) The three familiar states of matter are solids, liquids, and ________.

143) ____________

144) Chemical reactions that occur in the body are accelerated by ________.

144) ____________

145) In living cells, complex metabolic reactions proceed in a series of steps called a(n)
________.

145) ____________

146) Compounds that contain carbon as the primary structural atom are called ________
molecules.

146) ____________


147) Compounds that do not usually contain carbon as the primary structural atom are called
________ molecules.

147) ____________


154) ____________

155) Individual steroids differ in the ________ attached to the carbon rings.

155) ____________

156) The molecule DNA contains a five-carbon sugar called ________.

156) ____________

157) The purines found in DNA are ________ and guanine.

157) ____________

158) The pyrimidine bases found in DNA are ________ and cytosine.

158) ____________

159) The three structural components of a nucleotide are a pentose, a phosphate group, and a
_______ base.

159) ____________

160) A(n) ________ is a covalent bond that stores an unusually large amount of energy.

160) ____________

161) In the process of ________ a phosphate group is transferred to a molecule.

161) ____________

15)
16)
17)
18)
19)
20)
21)
22)
23)
24)
25)
26)
27)
28)
29)
30)
31)
32)
33)
34)
35)
36)
37)
38)
39)
40)
41)
42)
43)
44)

C
B
E
D
C
C
D
A
A
A
B
D
B
B
D
E
D
D
C
A
B
B
A
B
C
D
A
C
C


81)
82)
83)
84)
85)
86)
87)
88)
89)
90)
91)
92)
93)
94)
95)
96)
97)
98)
99)
100)
101)
102)
103)

D
B
A
C
D
A

E
A
D
D
B
D
E
A
C
C
C
D
E
A
B
B


104)
105)
106)
107)
108)
109)
110)
111)
112)
113)
114)
115)

146)
147)
148)
149)
150)
151)
152)
153)
154)
155)

E
E
D
D
E
D
D
A
C
D
B
A
C
C
B
C
E
C
D

micelles
phospholipids
side chains


156)
157)
158)
159)
160)
161)
162)
163)

deoxyribose
adenine
thymine
nitrogenous
high-energy bond
phosphorylation
energy
The number of neutrons in an atom is equal to the mass number minus the atomic number. Thus, sulfur has 32 - 16
= 16 neutrons. The atomic number indicates the number of protons, so a neutral sulfur atom contains 16 protons
plus 16 electrons to balance the protons electrically. The electrons would be distributed as follows: 2 in the first
electron shell, 8 in the second, and the remaining 6 in the third. To achieve a full 8 electrons in the third (outermost)
electron shell, the sulfur atom can accept 2 electrons in an ionic bond or can share 2 electrons in a covalent bond.
Because hydrogen atoms can share one electron in a covalent bond, the sulfur atom can form two covalent bonds
with hydrogen, one with each of two hydrogen atoms. In chemical notation, this is H 2S.

164) Buffer systems help maintain pH within normal limits by removing or replacing hydrogen ions as needed.