Biochemistry Plus Review 2016
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by
A) polar covalent bonds.
B) ionic bonds.
C) van der Waals interactions.
D) nonpolar covalent bonds.
E) hydrogen bonds.
1)
2) The partial negative charge in a molecule of water occurs because
A) the electrons shared between the oxygen and hydrogen atoms spend more time around the
oxygen atom’s nucleus than around the hydrogen atom’s nucleus.
B) the oxygen atom acquires an additional electron.
C) the oxygen atom has two pairs of electrons in its valence shell that are not neutralized by
hydrogen atoms.
D) the oxygen atom forms hybrid orbitals that distribute electrons unequally around the oxygen
nucleus.
E) one of the hydrogen atoms donates an electron to the oxygen atom.
2)
3) Water molecules are able to form hydrogen bonds with
A) oils.
B) compounds that have polar covalent bonds.
C) any compound that is not soluble in water.
D) chloride ions.
E) oxygen gas (O 2 ) molecules.
3)
4) Which of the following takes place as an ice cube cools a drink?
A) Molecular collisions in the drink increase.
B) A calorie of heat energy is transferred from the ice to the water of the drink.
C) Kinetic energy in the drink decreases.
D) Evaporation of the water in the drink increases.
E) The specific heat of the water in the drink decreases.
4)
5) Liquid waterʹs high specific heat is mainly a consequence of the
A) small size of the water molecules.
B) fact that water is a poor heat conductor.
C) high specific heat of oxygen and hydrogen atoms.
D) higher density of liquid water than solid water (ice).
E) absorption and release of heat when hydrogen bonds break and form.
5)
6) Why does ice float in liquid water?
A) Ice always has air bubbles that keep it afloat.
B) Hydrogen bonds stabilize and keep the molecules of ice farther apart than the water
molecules of liquid water.
C) The crystalline lattice of ice causes it to be denser than liquid water.
D) The high surface tension of liquid water keeps the ice on top.
E) The ionic bonds between the molecules in ice prevent the ice from sinking.
6)
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7) What is the pH of a solution with a hydroxyl ion (OH - ) concentration of 10-12 M?
A) pH 14
B) pH 2
C) pH 10
D) pH 12
7)
E) pH 4
8) If the pH of a solution is decreased from 9 to 8, it means that the
A) concentration of H + has increased tenfold (10X) compared to what it was at pH 9.
8)
B) concentration of H + has decreased to one-tenth (1/10) what it was at pH 9.
C) concentration of OH - has increased tenfold (10X) compared to what it was at pH 9.
D) concentration of OH - has decreased to one-tenth (1/10) what it was at pH 9.
E) concentration of H + has increased tenfold (10X) and the concentration of OH - has decreased
to one-tenth (1/10) what they were at pH 9.
9) A carbon atom is most likely to form which of the following bonds with other atoms?
A) ionic bonds, covalent bonds, and hydrogen bonds
B) hydrogen bond
C) covalent bond
D) covalent bonds and hydrogen bonds
E) ionic bond
9)
10) Which two functional groups are always found in amino acids?
A) hydroxyl and carboxyl
B) ketone and methyl
C) amino and sulfhydryl
D) carboxyl and amino
E) carbonyl and amino
10)
11) What is the chemical reaction mechanism by which cells make polymers from monomers?
A) dehydration reactions
B) hydrolysis
C) phosphodiester linkages
D) the formation of disulfide bridges between monomers
E) ionic bonding of monomers
11)
12) How many molecules of water are needed to completely hydrolyze a polymer that is 11 monomers
long?
A) 9
B) 12
C) 11
D) 10
E) 8
12)
13) The molecular formula for glucose is C 6 H12O6 . What would be the molecular formula for a
13)
molecule made by linking three glucose molecules together by dehydration reactions?
A) C18H10O15
B) C18H32O16
C) C18H36O18
D) C6 H10O5
E) C3 H6 O3
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14) Which of the following is true of cellulose?
A) It is a polymer composed of enantiomers of glucose, it is a storage polysaccharide for energy
in plant cells, it is digestible by bacteria in the human gut, and it is a major structural
component of plant cell walls.
B) It is a polymer composed of enantiomers of glucose.
C) It is a major structural component of plant cell walls.
D) It is a storage polysaccharide for energy in plant cells.
E) It is digestible by bacteria in the human gut.
14)
15) Why are hydrocarbons insoluble in water?
A) They are lighter than water.
B) The majority of their bonds are polar covalent carbon-to-hydrogen linkages.
C) They are hydrophilic.
D) The majority of their bonds are nonpolar covalent carbon-to-hydrogen linkages.
E) They exhibit considerable molecular complexity and diversity.
15)
16) There are 20 different amino acids. What makes one amino acid different from another?
A) different side chains (R groups) attached to an α carbon
B) different side chains (R groups) attached to a carboxyl carbon
C) different structural and optical isomers
D) different asymmetric carbons
E) different side chains (R groups) attached to the amino groups
16)
17) What maintains the secondary structure of a protein?
A) hydrogen bonds between the R groups
B) hydrophobic interactions
C) hydrogen bonds between the amino group of one peptide bond and the carboxyl group of
another peptide bond
D) disulfide bonds
E) peptide bonds
17)
18) The tertiary structure of a protein is the
A) organization of a polypeptide chain into an α helix or β pleated sheet.
B) bonding together of several polypeptide chains by weak bonds.
C) order in which amino acids are joined in a polypeptide chain.
D) unique three-dimensional shape of the fully folded polypeptide.
E) overall protein structure resulting from the aggregation of two or more polypeptide subunits.
18)
19) The R group or side chain of the amino acid serine is -CH2 -OH. The R group or side chain of the
19)
amino acid leucine is -CH2 -CH-(CH3 )2 . Where would you expect to find these amino acids in a
globular protein in aqueous solution?
A) Both serine and leucine would be in the interior and on the exterior of the globular protein.
B) Leucine would be in the interior, and serine would be on the exterior of the globular protein.
C) Serine would be in the interior, and leucine would be on the exterior of the globular protein.
D) Both serine and leucine would be on the exterior of the globular protein.
E) Both serine and leucine would be in the interior of the globular protein.
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20) If cells are grown in a medium containing radioactive 35S, which of these molecules will be
labeled?
A) nucleic acids
B) both proteins and nucleic acids
C) proteins
D) amylose
E) phospholipids
20)
21) Which of the following statements about the 5ʹ end of a polynucleotide strand of RNA is correct?
A) The 5ʹ end has a hydroxyl group attached to the number 5 carbon of ribose.
B) The 5ʹ end has a phosphate group attached to the number 5 carbon of ribose.
C) The 5ʹ end is the fifth position on one of the nitrogenous bases.
D) The 5ʹ end has phosphate attached to the number 5 carbon of the nitrogenous base.
E) The 5ʹ end has a carboxyl group attached to the number 5 carbon of ribose.
21)
22) One of the primary functions of RNA molecules is to
A) make a copy of itself, thus ensuring genetic continuity.
B) transmit genetic information to offspring.
C) form the genes of higher organisms.
D) act as a pattern or blueprint to form DNA.
E) function in the synthesis of proteins.
22)
23) Which of the following descriptions best fits the class of molecules known as nucleotides?
A) a nitrogenous base and a phosphate group
B) a pentose sugar and a purine or pyrimidine
C) a nitrogenous base, a phosphate group, and a pentose sugar
D) a phosphate group and an adenine or uracil
E) a nitrogenous base and a pentose sugar
23)
24) Which of the following statements best summarizes the differences between DNA and RNA?
A) DNA encodes hereditary information, whereas RNA does not.
B) DNA encodes hereditary information, whereas RNA does not; the bases in DNA form
base-paired duplexes, whereas the bases in RNA do not; and DNA nucleotides contain a
different sugar than RNA nucleotides.
C) The bases in DNA form base-paired duplexes, whereas the bases in RNA do not.
D) DNA nucleotides contain a different sugar than RNA nucleotides.
E) DNA contains the base uracil, whereas RNA contains the base thymine.
24)
25) If one strand of a DNA molecule has the sequence of bases 5ʹATTGCA3ʹ, the other complementary
strand would have the sequence
A) 5ʹUAACGU3ʹ.
B) 5ʹUGCAAU3ʹ.
C) 3ʹUAACGU5ʹ.
D) 5ʹTGCAAT3ʹ.
E) 5ʹTAACGT3ʹ.
25)
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Answer Key
Testname: BIOCHEM EXTRA REVIEW 2015
1) A
2) A
3) B
4) C
5) E
6) B
7) B
8) E
9) C
10) D
11) A
12) D
13) B
14) C
15) D
16) A
17) C
18) D
19) B
20) C
21) B
22) E
23) C
24) D
25) D
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