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AP Biology
Unit 1 Homework Set (CH. 2 – 6)
Name: ____________________
Instructions:
Read each question carefully before answering. Work at a steady pace, and you should have
ample time to finish.
-----------------------------------------------------------___ 1. The atomic number of neon is 10. Therefore, it
1. has 8 electrons in the outer electrons shell.
2. is inert.
3. has an atomic mass of 10.
a. 1
b. 2
c. 3
d. Only 1 and 2 are correct
e. 1, 2, and 3 are correct.
___ 2. An atomic form of an element containing different numbers of neutrons is
a. an isotope.
b. an ion.
c. a polar atom.
d. an isomer.
e. radioactive.
___ 3. What are the chemical properties of atoms whose outer electron shells contain eight
electrons?
a. They form ionic bonds in aqueous solutions.
b. They form covalent bonds in aqueous solutions.
c. They are particularly stable and nonreactive
d. The tend to be gases.
e. They are particularly stable and nonreactive AND they tend to be gases.
-----------------------------------------------------------Use the choices below to answer the following question(s). Each choice may be used
once, more than once, or not at all.
1. nonpolar covalent molecule
2. polar covalent bond
3. ionic bond
4. hydrogen bond
5. hydrophobic interaction
UNIT 1 HOMEWORK SET (CH. 2 – 6)
Page 1
___ 4. Results from a transfer of election(s) between atoms.
a. 1
b. 2
c. 3
d. 4
e. 5
___ 5. Results from an unequal sharing of elections between atoms.
a. 1
b. 2
c. 3
d. 4
e. 5
___ 6. What is the maximum number of covalent bonds an element with atomic number 15 can
make with hydrogen?
a. 1
b. 2
c. 3
d. 4
e. 0
-----------------------------------------------------------Use the information extracted from the periodic table in Figure 2.1 to answer the
following question(s).
Atomic Mass -------->
Atomic Number ---->
12
16
1
14
32
31
C
O
H
N
S
P
6
8
1
7
16
15
Figure 2.1
___ 7. How many electrons does carbon have in its outermost (valence) energy level?
a. 4
b. 8
c. 7
d. 5
e. 2
___ 8. The atomic number of each atom is given at left. Which of the atoms has the same
valence as carbon?
a. 7 nitrogen
b. 9 fluorine
c. 10 neon
UNIT 1 HOMEWORK SET (CH. 2 – 6)
Page 2
d. 12 magnesium
e. 14 silicon
___ 9. Which of the following is a trace element that is essential to humans?
a. nitrogen
b. calcium
c. iodine
d. carbon
e. oxygen
___10. A covalent bond is likely to be polar when
a. one of the atoms sharing electrons is much more electronegative than the other.
b. the two atoms sharing electrons are equally electronegative.
c. the two atoms sharing electrons are of the same element.
d. it is between two atoms that are both very strong electron acceptors.
e. it joins a carbon atom to a hydrogen atom.
___ 11. What bonds are easily disrupted in aqueous solutions?
a. covalent
b. polar covalent
c. ionic
d. only covalent and polar covalent
e. covalent, polar
___ 12. From its atomic number of 15, it is possible to predict that the phosphorus atom has
a. 15 neutrons
b. 15 protons
c. 15 electrons.
d. 15 protons and 15 electrons.
e. 15 neutrons, 15 protons, and 15 electrons.
___ 13. The ionic bond of sodium chloride is formed when
a. chlorine gains an electron from sodium.
b. sodium and chlorine share an electron pair.
c. sodium and chlorine both lose electrons from their outer energy levels.
d. sodium gains a electron from chlorine.
e. chlorine gains a proton from sodium.
___ 14. Magnesium has the atomic number of 12. What kind of bonds does it form with chlorine
(atomic number of 17) and what is the formula for magnesium chloride?
a. covalent, MgCl
b. ionic, MgC2
c. covalent, Mg2Cl
d. ionic, MgCl
e. ionic, ClMg
UNIT 1 HOMEWORK SET (CH. 2 – 6)
Page 3
-----------------------------------------------------------Refer to Figure 2.2 to answer the following question(s).
___ 15. Which of the drawings depicts the electron configuration of neon?
___ 16. Which of the drawings depicts the electron configuration of the carbon?
-----------------------------------------------------------Refer to the numbers below to answer the following questions. Each number may be
used once, more than once, or not at all.
1
2
3
4
5
___ 17. The number of electrons carob shares with oxygen molecules in a molecule of CO 2.
a. 1
b. 2
c. 3
d. 4
e. 5
___ 18. The maximum number of electrons in the 1s orbital.
a. 1
b. 2
c. 3
d. 4
e. 5
___ 19. Which four elements make up approximately 96% of living matter?
a. carbon, hydrogen, nitrogen, and oxygen
b. carbon, sulfur, phosphorus, and hydrogen
c. oxygen, hydrogen, calcium, sodium
d. carbon, sodium, chlorine, magnesium
e. carbon, oxygen, sulfur, calcium
UNIT 1 HOMEWORK SET (CH. 2 – 6)
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___ 20. How many electrons would be expected in the outer energy level of an atom with an
atomic number 17?
a. equal numbers of isotopes.
b. ions.
c. polar covalent bonds.
d. nonpolar covalent bonds.
e. ionic bonds.
___ 22. The combining properties of an atom depend on the number of
a. valence shells in the atom.
b. orbital found in the atom.
c. electrons in each orbital in the atom.
d. electrons in the outer valence shell in the atom.
e. hybridized orbital in the atom.
___ 23. Atoms whose outer electron shells contain eight electrons tend to
a. form ionic bonds in aqueous solutions.
b. form covalent bonds in aqueous solutions.
c. be particularly stable and nonreactive.
d. be particularly unstable and very reactive.
e. be biologically important since they are present in organic molecules.
24. A covalent chemical bond is one in which
a. electrons are removed from one atom and transferred to another atom so that the two
atoms become oppositely charged.
b. protons or neutrons are shared by two atoms so as to satisfy the requirements of both.
c. outer shell electrons are shared by two atoms so as to satisfactorily fill the outer
electron shells of both.
d. outer shell electrons on one atom are transferred to the inner electron shells of another
atom.
e. the inner shell electrons of one atom are transferred to outer shell of another atom.
___ 25. If atom 6X (atomic number 6) were allowed to react with hydrogen, the molecule formed
would be
a. X – H
b. H – X – H
c. H – X – H
H
d.
H
H–X–H
H
UNIT 1 HOMEWORK SET (CH. 2 – 6)
Page 5
e. H = X = H
___ 26. The partial negative charge at one end of a water molecule is attracted to the partial
positive charge of another water molecule. What is this attraction called?
a. a covalent bond
b. a hydrogen bond
c. a am ionic bond
d. a hydration shell
e. a hydrophobic bond
___ 27. Life on earth is dependant on all the properties of water as well as the abundance of
water. Which property of water is probably most important for the functioning of organisms at
the molecular level?
a. cohesion and high surface tension
b. high specific heat
c. high hear of vaporization
d. expansion upon freezing
e. versatility as a solvent
___ 28. What would be the pH of a solution with a hydroxyl ion concentration (OH-) of 10?
a. 2
b. 4
c. 8
d. 10
e. 14
___ 29. Which of the following statements about water is correct?
a. Water is more dense as a solid than it is as a liquid
b. Water is more dense at 100 C than it is at 37 C.
c. Water is a good solvent for lipids.
d. Compared to most other substances, the temperature of water rises sharply when it
absorbs heat.
e. Compared to most liquids, the evaporation of water requires a large amount of heat.
___ 30. What do the following have in common with reference to water: cohesion, surface
tension, specific heat?
a. All are products of the structure of the hydrogen atom.
b. All are produced by covalent bonds.
c. All are properties related to hydrogen bonding.
d. All have to do with polarity of water molecules.
e. All are aspects of a semi-crystalline structure.
___ 31. Assume that acid rain has lowered the pH of a particular lake to pH 5.0. What is the
hydroxide ion concentration of this lake?
1. 1 x 10-5 moles of hydroxide ion per liter of lake water
2. 1 x 10-9 moles of hydroxide ion per liter of lake water.
UNIT 1 HOMEWORK SET (CH. 2 – 6)
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3. 5.0 molar with regard to hydroxide ion concentration
4. 9.0 molar with regard to hydroxide ion concentration.
a. 1
b. 2
c. 3
d. 4
e. Both 2 and 4 are correct.
___ 32. The nutritional information on a cereal box shows that one serving of dry cereal has 90
calories (large C). If one were to burn a serving of cereal in a bomb calorimeter, the
amount of heat given off would be sufficient to raise the temperature of one kilogram of
water how many degrees Celsius?
a. 0.9 Celsius
b. 9.0 Celsius
c. 90.0 Celsius
d. 900.0 Celsius
e. 9000.0 Celsius
___ 33. The formation of ice during colder weather helps to temper the seasonal transition to
winter. This is mainly because
a. the formation of hydrogen bonds releases heat.
b. the formation of hydrogen bonds absorbs heat.
c. there is less evaporative cooling of lakes.
d. ice melts each autumn afternoon.
e. ice is warmer than the winter air.
___ 34. The molecular mass of glucose is 180g. To make a one-molar solution of glucose, you
should do which of the following?
a. Dissolve 100g of glucose in a liter of water.
b. Dissolve 180g of glucose in a gallon water.
c. Dissolve 180g of glucose in 100 grams of water.
d. Dissolve 180mg (milligrams) of glucose in one liter of water.
e. Dissolve 180g of glucose in water, and then add more water until the toal volume of
the solution is one liter.
___ 35. In a lake contaminated by acid rain, fish generally die when the water is persistently
below which pH?
a. 8
b. 7
c. 6.5
d. 6
e. 5
-----------------------------------------------------------Refer to Figure 3.2 to answer the following question(s).
UNIT 1 HOMEWORK SET (CH. 2 – 6)
Page 7
Atomic Mass -------->
Atomic Number ---->
1.008
12.00
14.0
16.0
H
C
N
O
1
6
7
8
H H
O
=
N – C – C – OH
H H
___ 36. How many grams of the molecule sown above would constitute a mole of the substance?
a. 32
b. 40
c. 75
d. 114
e. 6.02 x 1023
___ 37. How would one make a 0.5-M solution of the molecule shown above?
1. Mix 0.5 grams with enough water to yield 1 liter of solution.
2. Mix 20 grams with enough water to yield 1 liter of solution.
3. Dissolve 37.5 grams with enough water to yield 1 liter of solution.
4. Dissolve 75 grams in a 0.5 liter of water.
a. 1
b. 2
c. 3
d. 4
e. Only 1 and 4 will yield a 0.5M solution?
___ 38. How many grams of the molecule show below should one add to a liter of water to make
a 0.2-M solution?
H O
||
H– C–C–O–H
H
a. 8
b. 12
c. 24
d. 32
e. 60
UNIT 1 HOMEWORK SET (CH. 2 – 6)
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___ 39. Which of the following ionizes completely in solution and is therefore a strong acid?
a. NaOH
b. H2CO3
c. CH3COOH
d. NH2
e. HCl
___ 40. It is correct to say that the action of buffers
a. is of relatively little significance in living systems.
b. tends to prevent great fluctuations in pH.
c. depends on the formation of a great number of hydrogen ions.
d. depends on the presence of many electron donors.
e. is to remove hydroxyl ions from organic acids.
___ 41. A given solution is found to contain 0.0001 mole of hydrogen ion (H+). Which of the
following best describes this solution?
a. acidic: H+ acceptor
b. basic: H+ acceptor
c. acidic: H+ donor
d. basic: H+ donor
e. neutral
___ 42. What do cohesion, surface tension, and adhesion have in common with reference to
water?
a. All are products of the structure of the hydrogen atom.
b. All are produced by covalent bonding.
c. All are properties related to hydrogen bonding.
d. All have to do with nonpolar covalent bonds.
e. All are aspects of crystalline structure.
-----------------------------------------------------------Use the terms below to answer the following question(s). Each term may be used once,
more than once, or not at all.
1. calorie
2. temperature
3. heat of vaporization
4. mole
___ 43. A measure of the average kinetic energy of the molecules in a body of matter.
a. 1
b. 2
c. 3
d. 4
e. 5
UNIT 1 HOMEWORK SET (CH. 2 – 6)
Page 9
___ 44. Which of the following is a correct definition of a kilocalorie?
a. The amount of heat required to raise 1 gram of water by one degree Fahrenheit.
b. The amount of heat energy required to raise 1 gram of water by ten degrees Celsius.
c. The amount of heat energy required to raise 1 kilogram of water by one degree Celsius.
d. A measure of the average kinetic energy of a pint of water.
e. The amount of energy in one kilogram of glucose.
___ 45. At what temperature is water at its densest?
a. 0° C
b. 4° C
c. 32° C
d. 100° C
e. 212° C
___ 46. A compound contains hydroxyl groups as its predominate functional group. Which of
the following statements is true concerning this compound?
a. It is probably a lipid.
b. I should dissolve in water.
c. It should dissolve in a non-polar solvent.
d. It won’t form hydrogen bonds with water.
e. It is hydrophobic.
___ 47. Which of the following elements is the most abundant (percent dry weight) in both
humans and E. coli?
a. oxygen
b. carbon
c. hydrogen
d. nitrogen
e. phosphorus
___ 48. What is the reason why hydrocarbons are not soluble in water?
a. They are hydrophilic
b. The C-H bond is non-polar.
c. They do not ionize
d. They are large molecules.
e. They are lighter than water.
___ 49. Glucose and fructose differ in
1. The number of carbon, hydrogen, and oxygen atoms
2. The types of carbon, hydrogen, and oxygen atoms.
3. The arrangement of carbon, hydrogen, and oxygen atoms.
a. 1
b. 2
c. 3
d. Only 1 and 2 are correct.
e. 1, 2, 3 are correct.
UNIT 1 HOMEWORK SET (CH. 2 – 6)
Page 10
___ 50. What is the name of the function groups below?
O
//
R–C
\
O–H
a. carbonyl
b. methyl
c. dehydroxyl
d. carbonxyl
e. acetyl
___ 51. Forms covalent cross links within or between protein molecules.
a. 1
b. 2
c. 3
d. 4
e. 5
___ 52. Polar confers solubility in water.
a. 1
b. 2
c. 3
d. 4
e. 5
___ 53. Which of the following contains nitrogen in addition to carbon, oxygen, and hydrogen?
a. alcohol such as ethanol
b. a compound such as glycerol
c. a steroid such as testosterone
d. amino acid such as glycine
e. a hydrocarbon such as benzene
-----------------------------------------------------------Refer to the molecule shown in Figure 4.4 to answer the following question(s).
1.
H H
| |
H – C – C – OH
| |
H H
2.
H H O
| |
//
C–C–H
\
H
UNIT 1 HOMEWORK SET (CH. 2 – 6)
3.
H O H
| || |
H–C–C–C–H
|
|
H
H
Page 11
4.
H O
| //
H–C–C
| \
H OH
5.
H
H
|
/
H–C–N
|
\
H
H
Figure 4.4
___ 54. Which molecule contains a carboxyl group?
a. 1
b. 2
c. 3
d. 4
e. 5
___ 55. Which two of the molecules above contain a carbonyl group?
a. 1 and 2
b. 2 and 3
c. 3 and 4
d. 4 and 5
e. 1 and 5
___ 56. Which of the above is water soluble because it has a functional group that is an alcohol?
a. 1
b. 2
c. 3
d. 4
e. 5
__ 57. Which of the following is a false statement concerning amine groups?
a. They are basic.
b. They are found in amino acids.
c. They contain nitrogen.
d. They are nonpolar
e. They are components of urea.
58. Which two functional groups are always found in amino acids?
a. amine and sulfhydryl
b. carbonyl and carboxyl
c. carbonxyl and amine
d. alcohol and aldehyde
e. ketone and amine
59. Which of the following is the best description of organic compounds?
a. carbon atoms covalently bonded to other carbon atoms
b. polymers composed of many monomer subunits
c. compounds with covalent bonds that are unequally shared with other atoms
d. compounds all containing carbon, hydrogen, oxygen, and nitrogen
UNIT 1 HOMEWORK SET (CH. 2 – 6)
Page 12
e. carbon compounds all having a linear order of atoms
60. Which functional groups can act as acids?
a. amine and sulfhydrl
b. carbonyl and carboxyl
c. carboxyl and phosphate
d. alcohol and aldehyde
e. ketone and amine
61. Which type of lipid is most important in biological membranes?
a. fats
b. steroids
c. phospholipids
d. oils
e. triglycerides
62. Which types of interaction stabilizes the alpha helix structure of proteins?
a. hydrophobic interactions
b. non-polar covalent bonds
c. ionic Interactions
d. hydrogen bonds
e. polar covalent bonds
63. What is the molecule illustrated below?
O
H H H H H H H H H H H H H H H
\\
|
|
| |
| |
|
| | |
| |
|
|
|
C–C–C–C–C–C–C–C–C–C–C–C–C–C–C–C–H
/
| | | | |
| | | | | | | | | |
OH H H H H H H H H H H H H H H H
a. a saturated fatty acid
b. An unsaturated fatty acid
c. a polyunsaturated triglyceride
d. likely to be a common component of plat oils
e. similar in structure to a steroid
64. What is the structure shown in Figure 5.2
Figure 5.2
a. a starch molecule
UNIT 1 HOMEWORK SET (CH. 2 – 6)
Page 13
b. a steroid
c. a protein
d. a cellulose molecule
e. a nucleic acid polymer
___ 65. Which of the following is true both of starch and of cellulose?
a. They are both polymers of glucose.
b. They are geometric isomers of each other.
c. They can both be digested by humans.
d. They are both used for energy storage in plants.
e. They are both structural components of the plant cell wall.
___ 66. Hydrolysis is involved in which of the following?
a. formation of starch
b. hydrogen bond formation between nucleic acids
c. peptide bond formation of proteins
d. the hydrophylic interactions of lipids
e. the digestion of maltose to glucose
___ 67. Large organic molecules are usually assembled by polymerization of a few kinds of
simple subunits. Which of the following is an exception to the above statement?
a. a steroid
b. a cellulose
c. DNA
d. an enzyme
e. a contractile protein
___ 68. At which level of protein structure are interactions between R-groups most important?
a. primary
b. secondary
c. tertiary
d. quaternary
e. They are equally important at all levels
___ 69. What maintains the secondary structure of a protein?
a. peptide bonds
b. hydrogen bonds
c. disulfide bridges
d. ionic bonds
e. electrostatic charges
___ 70. Condensation synthesis reactions are used in forming which of the following
compounds?
a. triglycerides
b. polysaccharides
c. proteins
UNIT 1 HOMEWORK SET (CH. 2 – 6)
Page 14
d. only triglycerides and proteins are correct
e. triglycerides, polysaccharides, and proteins
UNIT 1 HOMEWORK SET (CH. 2 – 6)
Page 15
___ 71. Which of the following is true concerning saturated fatty acids?
a. They have double bonds between the carbon atoms of the fatty acids.
b. They have a higher ratio of hydrogen to carbon than unsaturated fatty acids.
c. They are usually liquid at room temperature.
d. They are usually produced by plants.
e. All of these are true.
___ 72. At which bond in Figure 5.4 would water need to be added to achieve hydrolysis of the
dipeptide shown, back to its component amino acids?
a. 1
b. 2
c. 3
d. 4
e. 5
___ 73. Altering which of the following levels of structural organizations of a protein could
alter the function of an enzyme?
a. primary
b. secondary
c. tertiary
d. only primary tertiary are correct
e. primary, secondary, and tertiary
___ 74. The structural feature that allows the DNA to replicate itself is the
a. sugar-phosphate backbone
b. complimentary pairing of the bases
c. phosphodiester bonding of the helices
d. twisting of the molecules to form an alpha helix
e. three part structure of the nucleotides
___ 75. If one strand of a DNA molecule has the sequence of bases 5’ –ATTGCA -3’, the other
strand would have the sequence
a. 3’ –TAACGT -5’
b. 3’ –TCCCGT -5’
c. 3’ –TUUCGU -5’
d. 3’ –TAAGCT -5’
e. 3’ –TUUGCU -5’
UNIT 1 HOMEWORK SET (CH. 2 – 6)
Page 16
___ 76. Which of the following would yield the most energy per gram when oxidized?
a. starch
b. glycogen
c. fat
d. protein
e. monosaccharides
___ 77. All of the follwing molecules are proteins EXCEPT
a. hemoglobin
b. antibodies
c. collagen
d. enzymes
e. DNA
___ 78. All of the following bases are found in DNA EXCEPT
a. thymine
b. adenine
c. uracil
d. guanine
e. cytosine
___ 79. Which of the following descriptions best first the class of molecules known as
nucleotides?
a. a nitrogen base and a phosphate group
b. a nitrogen bas and a five-carbon group
c. a nitrogen base, a phosphate group, and a five-carbon sugar
d. a five-carbon sugar and adenine or uracil
e. a five-carbon sugar and purine
___ 80. The tertiary structure of a protein is the
a. bonding together of several polypeptide chains by weak bonds
b. order in which amino acids are joined in a peptide chain
c. bonding of two amino acids together to from a dipeptide
d. folding of a peptide chain into an alpha helix
e. folding of the alpha helix
___ 81. Which of the following illustrates hydrolysis?
a. the reaction of two monosaccharides to from a disaccharide with the release of water
b. the synthesis of two amino acids to form a dipeptide with the utilization of water
c. the reaction of a fat to form glycerol ad fatty acids with the release of water
d. the reaction of a fat to form glycerol and fatty acids with the utilization of water
e. the synthesis of a nucleotide from a phosphate , a ribose sugar, and a nitrogen base
with the production of a molecule of water
___ 82. What is a common feature of both starch and glycogen?
UNIT 1 HOMEWORK SET (CH. 2 – 6)
Page 17
a. Both form microfibrils that give support to connective tissue fibers.
b. Both contain repeated monomers of glucose and galactose.
c. They are important structural components of plant cell walls.
d. They are polymers of glucose.
e. They are water-soluble disaccharides.
-----------------------------------------------------------Refer to Figure 5.6 (based on the molecules illustrated) to answer the following
questions(s).
___ 83. An amino acid.
a. 1
b. 2
c. 3
d. 4
e. 5
___ 84. A structural component of cell membranes.
a. 1
b. 2
c. 3
d. 4
e. 5
UNIT 1 HOMEWORK SET (CH. 2 – 6)
Page 18
___ 85. Polysaccharides, lipids, and proteins are similar in that they
a. are synthesized from monomers by the process of hydrolysis.
b. are synthesized from monomers by the process of dehydration synthesis.
c. are synthesized by peptide bonding between amino acids.
d. are decomposed into their subunits by the process of dehydration synthesis.
e. all contain nitrogen in their monomers.
___ 86. How does an enzyme catalyze a reaction?
a. by supplying the energy to speed up a reaction
b. by lowering the energy of activation of a reaction
c. by lowering the ⌂G of a reaction
d. by changing the equilibrium of a spontaneous reaction
e. by increasing the amount of free energy of a reaction
___ 87. Why is ATP an important molecule in metabolism?
a. It has high energy phosphate bonds.
b. Its phosphate bonds are easily made and broken.
c. Its hydrolysis is endergonic.
d. It is readily obtained from an organism’s environment.
e. It is extremely stable.
___ 88. Which of the following would decrease the entropy within a system?
a. dehydration synthesis
b. hydrolysis
c. respiration
d. digestion
e. catabolism
___ 89. Increasing the substrate concentration in an enzymatic reaction could overcome which
of the following?
a. denaturing of the enzyme
b. allosteric inhibition
c. competitive inhibition
d. noncompetitive inhibition
e. insufficient cofactors
___ 90. Whenever energy is transformed, there is always an increase
a. in the free energy of the system.
b. in the free energy of the universe.
c. in the entropy of the system.
d. in the entropy of the universe.
e. in the enthalpy of the universe.
___ 91. Which of the following is true of exergonic reactions?
a. The products have more potential energy than the reactants.
UNIT 1 HOMEWORK SET (CH. 2 – 6)
Page 19
b. They products have less potential energy than the reactants.
c. Reactants will always be completely converted to products.
d. A net input of energy from the surrounds is required for the reactions to proceed.
e. The reactions upgrade the chemical energy in the products at the expense of energy
from the surroundings
___ 92. ATP generally energizes a cellular process by
a. releasing heat upon hydrolysis.
b. acting as a catalyst.
c. direct chemical transfer of phosphate group.
d. releasing ribose electrons to drive reactions.
e. emitting light flashes.
___ 93. A solution of starch at room temperature does not spontaneously decompose rapidly to a
sugar solution because
a. the start solution has less free energy than the sugar solution.
b. the hydrolysis of starch to sugar is endergonic.
c. the activation energy barrier cannot be surmounted by most of the starch molecules.
d. starch cannot be hydrolyzed in the presence of so much water.
e. starch hydrolysis is non spontaneous.
___ 94. According to the second law of thermodynamics, all of the following are true EXCEPT
a. the synthesis of large molecules from small molecules is exergonic.
b. the Earth is not a closed system.
c. life exists at the expense of greater energy than it contains.
d. entropy increase in a closed system.
e. every chemical transformed represents a loss of free energy.
___ 95. A chemical reaction that has positive ⌂G is correctly described as
a. endergonic
b. exergonic
c. enthalpic
d. spontaneous
e. exothermic
___ 96. Which of the statements regarding enzymes is false?
a. Enzymes are proteins that function as catalysts.
b. Enzymes display specificity for certain molecules to which they attach.
c. Enzymes provide activation energy for the reactions they catalyze.
d. The activity of enzymes can be regulated by factors in their immediate environment.
e. An enzyme may be used many times over for a specific reaction.
-----------------------------------------------------------Refer to the following information to answer the question(s).
A series of enzymes catalyze the reaction X  Y  Z  A.
UNIT 1 HOMEWORK SET (CH. 2 – 6)
Page 20
Product “A” binds to the enzyme that converts X to Y at a position remote from its active
site. This binding decreases the activity of the enzyme.
___ 97. In this example substance X is
a. a coenzyme.
b. an allosteric inhibitor.
c. a substance
d. an intermediate.
e. the product.
___ 98. Which of the following statements is true concerning catabolic pathways?
a. They combine molecules into more complex and energy rich molecules.
b. They are usually coupled with anabolic pathways to which they supply energy in the
from of ATP.
c. They involve endergonic reactions that break complex molecules into simpler ones.
d. They are spontaneous and do not need enzyme catalysis.
e. They build up complex molecules such as protein from simpler compounds.
___ 99. According to the induced fit hypothesis of enzyme function, which of the following is
correct?
a. The binding of the substrate depends on the shape of the active site.
b. Some enzymes become denatured which activators bind to the substrate.
c. A competitive inhibitor can out-compete the substrate for the active site.
d. The binding of the substrate changes the shape of the enzyme slightly and may stress
of bend substrate bonds.
e. The active site creates a microenvironment of ideal for the reaction.
___ 100. Correct statements regarding ATP include:
I. ATP (adenoside triphosphate) serves as the main energy shuttle in cells.
II. ATP drives endergonic reaction in the cell by the enzymatic transfer of the phosphate
group to specific reactants.
III. The regeneration of ATP from ADP and phosphate is an endergonic reaction
a. I only
b. II only
c. III only
d. I and III only
e. I, II and III
UNIT 1 HOMEWORK SET (CH. 2 – 6)
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