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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. 2) _______
A) protons + neutrons
B) electrons
C) protons + electrons
D) protons
E) neutrons
3) The "atomic weight" of an atom reflects the average number of 3) _______
A) electrons.
B) protons.
C) protons + neutrons + electrons.
D) neutrons.
E) protons + neutrons.
4) One mole of any element 4) _______
A) has the same number of electrons.
B) has the same mass.
C) has the same weight.
D) has the same number of atoms.
E) All of the answers are correct.
5) The nucleus of an atom consists of 5) _______
A) protons + neutrons.
B) protons.
C) protons + electrons.
D) electrons.
E) neutrons.
6) Isotopes of an element differ in the number of 6) _______
A) neutrons in the nucleus.
B) electrons in energy shells.
C) electrons in the nucleus.
D) protons in the nucleus.
E) electron clouds.
7) The mass number represents the number of 7) _______
A) electrons in an ion.
B) protons + neutrons.
C) neutrons + electrons.
D) protons in an atom.
E) neutrons in an atom.
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 9) _______
A) isotopes.
B) protons.
C) nuclei.
D) electron clouds.
E) ions.
10) By weight, which element is the most plentiful in the human body? 10) ______
A) sodium
B) sulfur
C) oxygen
D) potassium
E) carbon
11) Indicate which of these lists contains only trace elements. 11) ______
A) selenium, hydrogen, calcium
B) sulfur, chlorine, oxygen
C) cobalt, calcium, sodium
D) silicon, fluorine, tin
E) boron, oxygen, carbon
12) The atomic number represents the number of 12) ______
A) electrons in an atom.
B) neutrons in an atom.
C) protons in an atom.
D) chemical bonds the atom may form.
E) protons and neutrons in an atom.
13) Helium (He) has an atomic number of 2. It is chemically stable because it 13) ______
A) is neutral in electrical charge.
B) will form a covalent bond with another He atom.
C) readily ionizes to react with other atoms.
D) lacks electrons, thus the He atom is stable.
E) has a full outer electron shell.
14) Which element commonly has only a proton as its nucleus? 14) ______
A) argon B) hydrogen C) carbon D) helium E) neon
15) By weight, which element is the second most abundant in the human body? 15) ______
A) calcium
B) oxygen
C) hydrogen
D) nitrogen
E) carbon
16) The mass of an atom is largely determined by the number of ________ it has. 16) ______
A) protons
B) electrons
C) neutrons
D) protons + neutrons
E) protons + electrons
17) If an isotope of oxygen has 8 protons, 10 neutrons, and 8 electrons, its mass number is 17) ______
A) 12. B) 16. C) 18. D) 8. E) 26.
18) If an element is composed of atoms with an atomic number of 6 and a mass number of 14, then a
neutral atom of this element contains
18) ______
A) 6 protons.
B) 8 electrons.
C) 8 neutrons.
D) 6 protons and 8 electrons.
E) 6 protons and 8 neurons.
19) The molecule NO is known as 19) ______
A) nitrous oxide.
B) nitric oxide.
C) nitric oxygen.
D) noxious oxygen.
E) noxious oxide.
20) The molecule CO2 is known as 20) ______
A) carbon monoxide.
B) carbonated oxygen.
C) carbonized oxygen.
D) carbon dioxide.
E) carbon oxide.
21) The molecule H2 is known as 21) ______
A) helium.
B) hydrohydrogen.
C) hydrogen.
D) hydroxide.
E) semi-water.
22) When electrons are transferred from one atom to another, and the two atoms unite as a result of
the opposite charges,
22) ______
A) an ionic bond is formed.
B) a molecule is formed.
C) an ion is formed.
D) a hydrogen bond is formed.
E) a covalent bond is formed.
23) Magnesium atoms have two electrons in the outermost shell. As a result, you would expect
magnesium to form ions with a charge of
23) ______
A) +1.
B) -2.
C) +2.
D) -1.
E) either +2 or -2.
24) Which of the following statements about hydrogen bonds is false? 24) ______
A) Hydrogen bonds are responsible for many of the properties of water.
B) Hydrogen bonds are strong attractive forces between hydrogen atoms and negatively
charged atoms.
C) Hydrogen bonds can form between neighboring molecules.
D) Hydrogen bonds can occur within a single molecule.
E) Hydrogen bonds are important for holding large molecules together.
25) The molecule O2 is known as 25) ______
A) organic. B) oxide. C) oxate D) a salt E) oxygen.
26) H2O is an example of a(n) 26) ______
A) covalent formula.
B) ion.
C) glucose molecule.
D) compound.
E) ionic formula.
27) Which of the following is not a cation? 27) ______
A) Ca2+ B) Na+ C) Cl- D) K+ E) Mg2+
28) A dust particle floating on a water surface illustrates 28) ______
A) hydrophilic attraction.
B) chemical tension.
C) surface tension.
D) heat capacity.
E) static electricity.
29) In an aqueous solution, cations are attracted toward 29) ______
A) salt.
B) hydrogen ions.
C) buffers.
D) anions.
E) sodium.
30) In an aqueous solution, sodium ions would move toward 30) ______
A) a negative terminal.
B) a positive terminal.
C) the bottom.
D) a pH terminal.
E) an organic terminal.
31) The chemical behavior of an atom is determined by 31) ______
A) the outermost electron shell.
B) the number of protons.
C) the mass of the nucleus.
D) the size of the atom.
E) the number of neutrons.
32) Ions with a + charge are called 32) ______
A) cations.
B) isotopes.
C) radicals.
D) positrons.
E) anions.
33) The weakest bond between two atoms is the ________ bond. 33) ______
A) ionic
B) hydrogen
C) covalent
D) polar
E) nonpolar
34) When atoms complete their outer electron shell by sharing electrons, they form 34) ______
A) hydrogen bonds.
B) cations.
C) anions.
D) covalent bonds.
E) ionic bonds.
35) Ionic bonds are formed when 35) ______
A) hydrogen forms bonds with negatively charged atoms.
B) an electron or electrons are completely transferred from one atom to another.
C) atoms share electrons.
D) two or more atoms lose electrons at the same time.
E) a pair of electrons is shared unequally by two atoms.
36) If a pair of electrons is unequally shared between two atoms, a(n) ________ occurs. 36) ______
A) double covalent bond
B) polar covalent bond
C) triple covalent bond
D) single covalent bond
E) hydrogen bond
37) Elements that have atoms with full outer shells of electrons 37) ______
A) will normally form cations.
B) frequently form hydrogen bonds.
C) will normally form anions.
D) are inert gases.
E) will form many compounds.
38) Ions in an ionic molecule are held together due to 38) ______
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.
39) An unequal sharing of electrons results in what type of chemical bonds? 39) ______
A) hydrogen
B) ionic
C) covalent
D) polar covalent
E) peptide
40) Sodium (Na) has an atomic number of 11. How many electrons are in the outer electron shell of a neutral
sodium
atom?
40) ___
___
A) 2 B) 8 C) 4 D) 1 E) 3
41) Oxygen (atomic number 8) requires how many additional electrons to fill its outer electron
shell?
41) ______
A) 8 B) 1 C) 2 D) 6 E) 4
42) The formula for methane gas is CH4. What does the formula 4CH4 represent? 42) ______
A) 4 molecules, each containing a carbon atom and 4 hydrogen atoms
B) a molecule with 4 carbon atoms and 16 hydrogen atoms
C) an inorganic compound with ionic bonds
D) a molecule with 4 carbon atoms
E) 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
________.
43) ______
A) salt, ion
B) cation, anion
C) anion, cation
D) base, acid
E) acid, base
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)
44) ______
A) double divalent bond.
B) triple covalent bond.
C) single trivalent bond.
D) hydrogen bond.
E) polar covalent bond.
45) In chemical notation, the symbol Ca2+ means ________. 45) ______
A) a calcium ion that has lost two electrons
B) a calcium ion that has lost two protons
C) a calcium ion that has gained two protons
D) two calcium atoms
E) a calcium ion that has gained two electrons
46) Magnesium atoms have two electrons in the outermost shell and chlorine atoms have seven. The
compound magnesium chloride would contain
46) ______
A) 1 magnesium and 1 chlorine.
B) 1 magnesium and 2 chlorine.
C) 2 magnesium and 7 chlorine.
D) 2 magnesium and 1 chlorine.
E) impossible to tell without more information
47) AB → A + B is to decomposition as A + B → AB is to 47) ______
A) combustion.
B) replacement.
C) synthesis.
D) metabolism.
E) exchange.
48) The reaction N2 + 3 H2 → 2 NH3 is an example of a(n) 48) ______
A) metabolic reaction.
B) decomposition reaction.
C) exchange reaction.
D) synthesis reaction.
E) enzyme reaction.
49) The reaction A + B + energy → AB is an example of a(n) 49) ______
A) endergonic reaction.
B) exergonic reaction.
C) equilibrium reaction.
D) exchange reaction.
E) decomposition reaction.
50) In hydrolysis reactions, compounds react with 50) ______
A) glucose, causing decomposition.
B) hydrogen, causing decomposition.
C) water, causing decomposition.
D) water, causing synthesis.
E) carbon, causing decomposition.
51) Which one of the following statements is not correct about the reaction H2 + Cl2 → 2 HCl? 51) ______
A) One molecule of hydrogen contains two atoms.
B) H2 and Cl2 are the reactants.
C) This reaction is easily reversible.
D) HCl is the product.
E) Two molecules of HCl are formed in the reaction.
52) In dehydration synthesis reactions, compounds 52) ______
A) gain water molecules.
B) convert water molecules to hydrogen and oxygen.
C) gain electrons.
D) lose water molecules.
E) convert hydrogen and oxygen to water.
53) In the reaction listed below, what coefficient needs to be added to balance the equation?
6 CO2 + 6 H2O → C6H12O6 + ________ O2
53) ______
A) 4 B) 6 C) 8 D) 2 E) 10
54) Chemical reactions that yield energy, such as heat, are said to be 54) ______
A) exergonic.
B) thermonuclear.
C) neutral.
D) activated.
E) endergonic.
55) All of the following are true concerning enzymes, except that they 55) ______
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.
E) are proteins.
56) Compounds that can be synthesized or broken down by chemical reactions inside the body are
called
56) ______
A) enzymes.
B) inorganic compounds.
C) nutrients.
D) metabolites.
E) organic compounds.
57) Each of the following is an example of an inorganic compound, except 57) ______
A) carbohydrates.
B) bases.
C) salts.
D) acids.
E) water.
58) Identify which of the following is both an anion and a compound: 58) ______
A) Na+ B) HCO3- C) Cl- D) NaCl E) K+
59) Nonpolar organic molecules are good examples of 59) ______
A) solutes.
B) electrolytes.
C) molecules that will dissociate when placed into water.
D) hydrophobic compounds.
E) hydrophilic compounds.
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
60) ______
A) electrolytes.
B) acids.
C) anions.
D) counterions.
E) cations.
61) Oppositely charged ions in solution are prevented from combining by 61) ______
A) water's nonpolar nature.
B) hydration spheres.
C) hydrogen bonding.
D) free radicals.
E) heat capacity of water.
62) An example of an inorganic substance is 62) ______
A) water and carbon dioxide.
B) water.
C) carbon dioxide.
D) fructose.
E) glycerol.
63) Hydrophilic molecules readily associate with 63) ______
A) hydrophobic molecules.
B) water molecules.
C) acids.
D) lipid molecules.
E) salts.
64) Which of the following statements about water is not correct? 64) ______
A) It is composed of polar molecules.
B) It has a relatively low heat capacity.
C) It is responsible for much of the mass of the human body.
D) It contains hydrogen bonds.
E) It can dissolve many substances.
65) Which property of water helps keeps body temperature stabilized? 65) ______
A) thermal inertia
B) kinetic energy
C) surface tension
D) reactivity
E) lubrication
66) Of the list below, which has the highest concentration of hydroxide ions? 66) ______
A) pH 1 B) pH 14 C) pH 7 D) pH 2 E) pH 10
67) Which pH is closest to normal body pH? 67) ______
A) pH 8 B) pH 4 C) pH 3 D) pH 2 E) pH 7
68) A(n) ________ removes hydrogen ions and a(n) ________ releases hydrogen ions. 68) ______
A) element; compound
B) molecule; acid
C) base; acid
D) compound; element
E) acid; base
69) An excess of hydrogen ions in the body fluids can have fatal results because this can 69) ______
A) change the shape of large complex molecules, rendering them nonfunctional.
B) change body fluid pH.
C) disrupt tissue functions.
D) break chemical bonds.
E) All of the answers are correct.
70) A solution containing equal numbers of hydrogen ions and hydroxide ions is 70) ______
A) basic.
B) in equilibrium.
C) acidic.
D) alkaline.
E) neutral.
71) The chemical notation that indicates concentration is represented as 71) ______
A) ||. B) (). C) <>. D) [ ]. E) {}.
72) If a substance has a pH that is greater than 7, it is 72) ______
A) acidic. B) alkaline. C) neutral. D) a salt. E) a buffer.
73) Which pH of the following is the most acidic? 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? 74) ______
A) pH 6 B) pH 4 C) pH 2 D) pH 3 E) pH 1
75) An important buffer in body fluids is 75) ______
A) H2O.
B) NaOH.
C) NaCl.
D) NaHCO3.
E) HCl.
76) Which of the following substances would be most acidic? 76) ______
A) stomach secretions, pH = 1
B) urine, pH = 6
C) lemon juice, pH = 2
D) tomato juice, pH = 4
E) white wine, pH = 3
77) Of the following choices, the pH of the least acidic solution is 77) ______
A) 1.0. B) 4.5. C) 6.0. D) 2.3. E) 12.0.
78) Which has the greater concentration of hydrogen ions, a substance with a pH of 5 or a substance
with a pH of 4?
78) ______
A) A pH of 4 is greater.
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.
79) In the body, inorganic compounds 79) ______
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.
80) When placed in water, an inorganic compound dissociates 99 percent, forming hydrogen ions
and anions. This compound would be
80) ______
A) a strong base.
B) a weak base.
C) a weak acid.
D) a salt.
E) a strong acid.
81) When a small amount of HCl or NaOH is added to a solution of Na2HPO4, the pH of the
solution barely changes. Based on these observations, all of the following are true concerning the
compound Na2HPO4, except
81) ______
A) Na2HPO4 adsorbs excess H+ and OH- directly onto the surface of its crystalline structure.
B) Na2HPO4 acts as a buffer.
C) Na2HPO4 is able to accept extra hydrogen ions from the HCl.
D) Na2HPO4 is able to donate hydrogen ions to the OH- from NaOH.
E) Na2HPO4 is a salt formed from reacting a strong base with a weak acid.
82) Carbohydrates, lipids, and proteins are classified as 82) ______
A) salts.
B) inorganic molecules.
C) organic molecules.
D) acids.
E) bases.
83) A functional group is best described as reoccurring clusters of 83) ______
A) atoms that greatly influence the chemical properties of molecules they are part of.
B) elements that form at high pH.
C) atoms that function in the body.
D) amino acids in a globular protein.
E) elements that occur in a salt.
84) Artificial sweeteners 84) ______
A) are usually not broken down by the body.
B) are always some form of carbohydrate.
C) provide the same number of calories as an equivalent amount of sucrose.
D) are naturally similar to sugars.
E) are inorganic sugar substitutes.
85) Fructose is 85) ______
A) a carbohydrate.
B) a hexose.
C) found in male reproductive fluids.
D) an isomer of glucose.
E) All of the answers are correct.
86) Molecules that have the same molecular formula but different structural formulas are called 86) ______
A) isotopes.
B) isozymes.
C) isomoles.
D) isotypes.
E) isomers.
87) The most important metabolic fuel molecule in the body is 87) ______
A) protein. B) sucrose. C) glucose. D) caffeine. E) vitamins.
88) A polysaccharide that is formed in liver and muscle cells to store glucose is 88) ______
A) lactose.
B) sucrose.
C) fructose.
D) cellulose.
E) glycogen.
89) The group of organic compounds containing carbon, hydrogen, and oxygen in a near 1:2:1 ratio
is defined as a
89) ______
A) carbohydrate.
B) lipid.
C) protein.
D) saturated fat.
E) nucleic acid.
90) An example of an organic substance is: 90) ______
A) sodium chloride
B) nitric oxide
C) carbonic acid
D) sucrose
E) oxygen
91) Carbohydrate molecules 91) ______
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.
92) When two monosaccharides undergo a dehydration synthesis, 92) ______
A) two new monosaccharides are formed.
B) a disaccharide is formed.
C) hydrolysis occurs.
D) a polysaccharide is formed.
E) a starch is formed.
93) To bond two monomers together, a molecule of water must be ________ to/from from
monomers. This process is called ________.
93) ______
A) added; hydrolysis
B) removed; crenation
C) added; denaturation
D) removed; dehydration synthesis
E) added; ionization
94) Lipids 94) ______
A) form essential structural components of cells.
B) cushion organs against shocks.
C) help to maintain body temperature.
D) provide a significant energy reserve.
E) All of the answers are correct.
95) A fatty acid that contains two or more double covalent bonds is said to be 95) ______
A) polyunsaturated.
B) hydrogenated.
C) saturated.
D) monounsaturated.
E) carboxylated.
96) Alaska Natives have a lower incidence of heart disease even though their diets are high in fat
and cholesterol. This may be due to the large amount of ________ in their diets.
96) ______
A) vitamins
B) prostaglandins
C) omega-3 fatty acids
D) triglycerides
E) oleic acid
97) Which of the following is/are needed to form a triglyceride molecule? 97) ______
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
98) A shortage of steroids in the body would result in a shortage of 98) ______
A) proteins.
B) glycogen.
C) sex hormones and plasma membranes.
D) sex hormones.
E) plasma membranes.
99) Most of the fat found in the human body is in the form of 99) ______
A) cholesterol.
B) prostaglandins.
C) monoglycerides.
D) triglycerides.
E) phospholipids.
100) Lipids that are produced by nearly every tissue in the body and act as local regulators are the 100) _____
A) phospholipids.
B) glycolipids.
C) steroids.
D) monoglycerides.
E) prostaglandins.
101) Cholesterol, phospholipids, and glycolipids are examples of 101) _____
A) structural lipids.
B) lipid drugs.
C) dietary fats.
D) prostaglandins.
E) steroids.
102) A fatty acid with no double bonds between carbon atoms is 102) _____
A) polyunsaturated.
B) saturated.
C) denatured.
D) dehydrated.
E) unsaturated.
103) Lipids are composed of fatty acids and 103) _____
A) polypeptides.
B) glycerol.
C) amino acids.
D) monosaccharides.
E) sugars.
104) The monomers of protein are 104) _____
A) fatty acids.
B) nitrogen base.
C) glucose.
D) nucleotides.
E) amino acids.
105) Substrate molecules bind to enzymes at the ________ sites. 105) _____
A) carboxyl B) amino C) neutral D) reactant E) active
106) You would expect a peptide bond to link 106) _____
A) two simple sugars.
B) two nucleotides.
C) a sugar and a peptide.
D) two amino acids.
E) a peptide and a fatty acid.
107) Each amino acid differs from another in the 107) _____
A) size of the amino group.
B) number of carboxyl groups.
C) number of peptide bonds in the molecule.
D) nature of the side chain.
E) number of central carbon atoms.
108) The term ________ means each enzyme catalyzes only one type of reaction. 108) _____
A) saturation
B) monoreactive
C) inertia
D) activation
E) specificity
109) A side chain on an amino acid is sometimes called ________. 109) _____
A) a polypeptide chain
B) fibrous or globular
C) nucleic acid
D) an R group
E) an isozyme
110) The alpha-helix and pleated sheet are examples of ________ protein structure. 110) _____
A) tertiary
B) quaternary
C) pentanary
D) secondary
E) primary
111) Interaction between individual polypeptide chains to form a protein complex is ________
structure.
111) _____
A) quaternary
B) tertiary
C) pentagonal
D) secondary
E) primary
112) Glycoproteins and proteoglycans are combinations of amino acids and 112) _____
A) lipids.
B) inorganic compounds.
C) carbohydrates.
D) fatty acids.
E) nucleic acids.
113) Which of the following is the symbol for an amino group? 113) _____
A) -COOH B) -OH C) -AMO D) -NH2 E) -PO3
114) The maximum rate of an enzyme reaction occurs at 114) _____
A) synthesis.
B) saturation limit.
C) hydrolysis.
D) reversible.
E) dehydration.
115) How would the lack of a cofactor for an enzyme affect that enzyme's function? 115) _____
A) The enzyme would not be able to function.
B) The enzyme would function more quickly.
C) The enzyme's function would not be altered.
D) The enzyme would function more slowly.
E) The enzyme would cease to function after reaching a maximum rate.
116) An example of an organic substance is: 116) _____
A) lipid and protein
B) nucleic acid
C) lipid, nucleic acid, and protein
D) lipid
E) protein
117) Molecules that store and process genetic information are the 117) _____
A) lipids.
B) steroids.
C) nucleic acids.
D) carbohydrates.
E) proteins.
118) An amino acid is to a protein as ________ is to a nucleic acid. 118) _____
A) a purine
B) a nucleotide
C) a proton
D) a neutron
E) a protein
119) A nucleotide consists of 119) _____
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.
120) According to the rules of complementary base pairing in nucleic acids, cytosine would pair with
the base
120) _____
A) uracil. B) thymine. C) adenine. D) cytosine. E) guanine.
121) Adenine and guanine are 121) _____
A) nucleotides represented by A and G.
B) purines represented by T and C.
C) purines represented by A and G.
D) pyrimidines represented by A and G.
E) pyrimidines represented by T and C.
122) The structure of RNA differs from DNA in that 122) _____
A) DNA contains pyrimidines but not purines.
B) RNA contains pyrimidines but not purines.
C) RNA contains purines but not pyrimidines.
D) the backbone of RNA contains ribose.
E) DNA contains purines but not pyrimidines.
123) The most abundant high-energy compound in cells is 123) _____
A) DNA.
B) adenosine triphosphate.
C) adenosine monophosphate.
D) RNA.
E) adenosine diphosphate.
124) A high-energy bond in ATP is present 124) _____
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.
125) The phosphorylation of adenosine forms 125) _____
A) 2ATP. B) ribose. C) ATP. D) ADP. E) AMP.
126) Identify the product formed from the phosphorylation of ADP. 126) _____
A) adenosine diphosphate
B) deoxyribonucleic acid
C) adenine
D) adenosine triphosphate
E) ribose
127) AMP + P → 127) _____
A) ADP B) DNA C) 2ADP D) ATP E) adenine
128) The average time between synthesis and breakdown is known as the ________ time. 128) _____
A) anabolism
B) metabolism
C) turnover
D) specificity
E) catabolism
129) Muscle proteins are destroyed after 17 days and then replaced. This is an example of 129) _____
A) disease.
B) surveillance.
C) specificity.
D) metabolic turnover.
E) surface tension.
130) Continuous breakdown and replacement of cellular molecules is termed 130) _____
A) metabolic turnover.
B) metabolism.
C) organic chemistry
D) anabolic turnover.
E) catabolic turnover.
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 ________. 134) ____________
135) The actual mass of an atom is known as its ________ ________. 135) ____________
136) Atoms of the same element whose nuclei contain the same number of protons, but
different numbers of neutrons, are called ________.
136) ____________
137) The ________ of a radioactive substance is the time required for 50 percent of a given
amount of radioisotope to decay.
137) ____________
138) Ions with a positive charge are called ________. 138) ____________
139) Ions with a negative charge are called ________. 139) ____________
140) Kinetic energy is stored as ________ energy when a spring is stretched. 140) ____________
141) Chemical reactions that release energy are called ________. 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) ____________
148) A(n) ________ is a homogeneous mixture containing a solvent and a solute. 148) ____________
149) Soluble inorganic compounds whose solutions will conduct an electric current are called
________.
149) ____________
150) Molecules that do not readily interact with water are called ________. 150) ____________
151) The ________ of a solution is the negative logarithm of the hydrogen ion concentration
expressed in moles per liter.
151) ____________
152) All fatty acids contain a functional group at one end called the ________. 152) ____________
153) In water, phospholipids tend to form tiny droplets with hydrophobic tails buried inside
called ________.
153) ____________
154) Molecules with two fatty acid chains and a phosphate group that form biological
membranes are called ________.
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) ____________
162) The hydrolysis of ATP yields ADP, phosphate ion, and ________. 162) ____________
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
163) The element sulfur has an atomic number of 16 and mass number of 32. How many neutrons are in the
nucleus of a sulfur atom? If sulfur forms covalent bonds with hydrogen, how many hydrogen atoms can
bond to one sulfur atom?
164) What role do buffer systems play in the human body?
165) Blood has a very narrow normal pH range but urine has a very broad normal pH range. What does that
indicate about the physiology of pH?
166) Explain the role of water molecules in polysaccharide formation.
167) How does the DNA molecule control the appearance and function of a cell?
1) C
2) D
3) C
4) D
5) A
6) A
7) B
8) B
9) C
10) C
11) D
12) C
13) E
14) B
15) E
16) D
17) C
18) E
19) B
20) D
21) C
22) A
23) C
24) B
25) E
26) D
27) C
28) C
29) D
30) A
31) A
32) A
33) B
34) D
35) B
36) B
37) D
38) E
39) D
40) D
41) C
42) A
43) B
44) B
45) A
46) B
47) C
48) D
49) A
50) C
51) C
52) D
53) B
54) A
55) C
56) D
57) A
58) B
59) D
60) A
61) B
62) A
63) B
64) B
65) A
66) B
67) E
68) C
69) E
70) E
71) D
72) B
73) C
74) E
75) D
76) A
77) E
78) A
79) C
80) E
81) A
82) C
83) A
84) A
85) E
86) E
87) C
88) E
89) A
90) D
91) D
92) B
93) D
94) E
95) A
96) C
97) C
98) C
99) D
100) E
101) A
102) B
103) B
104) E
105) E
106) D
107) D
108) E
109) D
110) D
111) A
112) C
113) D
114) B
115) A
116) C
117) C
118) B
119) C
120) E
121) C
122) D
123) B
124) E
125) E
126) D
127) A
128) C
129) D
130) A
131) element
132) nucleus
133) electron cloud
134) energy levels
135) atomic weight
136) isotopes
137) half-life
138) cations
139) anions
140) potential
141) exergonic
142) endergonic
143) gases
144) enzymes
145) pathway
146) organic
147) inorganic
148) solution
149) electrolytes
150) hydrophobic
151) pH
152) carboxylic acid group
153) micelles
154) phospholipids
155) side chains
156) deoxyribose
157) adenine
158) thymine
159) nitrogenous
160) high-energy bond
161) phosphorylation
162) energy
163) 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 H2S.
164) Buffer systems help maintain pH within normal limits by removing or replacing hydrogen ions as needed.
165) Homeostasis requires that the pH of body fluids be maintained almost constant to avoid disruptions of healthy
function. To accomplish this, the urinary system eliminates or retains hydrogen ion as needed. These actions cause
the pH of urine to vary widely, depending on whether there is too much or not enough hydrogen ion in the body.
166) Water molecules are removed in the dehydration synthesis of polysaccharides.
167) The DNA molecule controls the synthesis of enzymes and structural proteins. By controlling the synthesis of
structural proteins, the DNA is able to influence the physical appearance of a cell. By controlling the production of
enzymes, the DNA is able to control all aspects of cellular metabolism and thus control the activity and biological
functions of the cell.
