BIOL 235 MIDTERM 2 Questions and ANSWERs
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a. the two atoms sharing electrons are equally electronegative
b. one of the atoms sharing electrons is more electronegative than the other atom
c. carbon is one of the two atoms sharing electrons
d. one of the atoms has absorbed more energy than the other atom
e. the two atoms sharing electrons are the same element - ANSWERb. one of the atoms sharing
electrons is more electronegative than the other atom-n(T1) Why are hydrocarbons insoluble in water?
a. The majority of their bonds are nonpolar covalent carbon-to-hydrogen linkages
b. The majority of their bonds are polar covalent carbon-to-hydrogen linkages
c. They are hydrophilic
d. They exhibit considerable molecular complexity and diversity
e. They are less dense than water - ANSWERa. The majority of their bonds are nonpolar covalent
carbon-to-hydrogen linkages-n(T1) Which of the following is NOT a function of proteins?
a. movement activity
b. catalytic activity
c. transport activity
d. defense activity
e. ribosome activity - ANSWERe. ribosome activity-n(T1) Which of the following occurs when a covalent
bond forms?
a. Electrons in valence shells are transferred from one atom to another
,b. Electrons in valence shells are shared between atoms
c. Partial charges on polar molecules interact
d. Nonpolar molecules are pushed together by surrounded water molecules - ANSWERb. Electrons in
valence shells are shared between atoms-n(T1) At which level of protein structure are interactions
between the side chains (R-groups) most important?
a. primary
b. secondary
c. tertiary
d. quaternary
e. primary, secondary, tertiary, and quaternary - ANSWERc. tertiary-n(T1) You disrupt all hydrogen
bonds in a protein. What level of structure will be preserved?
a. primary structure
b. secondary structure
c. tertiary structure
d. quaternary structure - ANSWERa. primary structure-n(T1) Of the following, which is a good working
definition of a gene?
a. any particular sequence of DNA or RNA
b. a DNA subunit that codes for a single complete protein
c. a nucleic acid sequence that encodes a trait
d. a sequence of nucleic acid that encodes one or more functional RNA molecules
e. a discrete unit of hereditary information that consists of a sequence of amino acids - ANSWERd. a
sequence of nucleic acid that encodes one or more functional RNA molecules-n(T1) Transcription
continues until:
a. all bases in the DNA are copied
b. a terminator sequence is encountered
,c. a stop codon is encountered
d. a ribosome pulls RNA polymerase off the DNA.
e. a transcription factor signals the end of the gene - ANSWERb. a terminator sequence in encountered-
n(T1) If a DNA sample were composed of 10% thymine, what would be the percentage of guanine?
a. 80
b. 40
c. 20
d. 10
e. It is impossible to tell from the information given - ANSWERb. 40-n(T1) Which of the following is TRUE
of DNA?
a. Successive nucleotides in a strand are connected by hydrogen bonds
b. A purine always forms a complementary base pair with a pyrimidine
c. A phosphate group in a nucleotide is attached to the 3- carbon in ribose
d. The percentage of the purine A always equals the percentage of the purine G
e. It is used by ribosomes for translation - ANSWERb. A purine always forms a complementary base pair
with a pyrimidine-n(T1) In transcription, the energy to attach each successive ribonucleotide to the
growing RNA chain comes from:
a. the RNA polymerase itself
b. cleavage/breakage of the high-energy phosphate bonds of the incoming nucleotide
c. cleavage/breakage of the high-energy phosphate bonds of the growing mRNA molecule
d. cleavage/breakage of the 3' hydroxyl group on the ribose of the incoming nucleotide
e. a ribosome - ANSWERb. cleavage/breakage of the high-energy phosphate bonds on the incoming
nucleotide-n(T1) In the process of transcription, _____.
a. DNA is replicated
, b. RNA is synthesized
c. proteins are synthesized
d. mRNA attaches to ribosomes - ANSWERb. RNA is synthesized-n(T1) How does the simple primary and
secondary structure of DNA hold the information needed to code for the many features of the
multicellular organisms?
a. The hydrogen bonding amonf backbone constituents carries coded information
b. The base sequence of DNA carries the information needed to code for RNA molecules
c. The width of the double helix changes at each gene due to differences in hydrogen bonds
d. The amino acids that make up the DNA molecule contain the information needed to make cellular
proteins - ANSWERb. The base sequence of DNA carries the information needed to code for RNA
molecules-n(T1) Nucleic acids have a definite polarity, or directionality. Stated another way, one end of
the molecule is different from the other end. How are these ends described?
a. One end has an -OH group on the 2' carbon; the other end has a phosphate group on the 2' carbon
b. One end has a nitrogenous base; the other end lacks a nitrogenous base
c. One end is at the 3' carbon; the other end is at the 5' carbon
d. One end has one phosphate group; the other end has three phosphate groups - ANSWERc. One end is
at the 3' carbon; the other end is at the 5' carbon-n(T1) Which of the following best describes DNA's
secondary structure?
a. beta-pleated sheet
b. two parallel helical strands
c. turn-loop-turn
d. two antiparallel helical strands - ANSWERd. two antiparallel helical strands-n(T1) Which of the
following did Watson and Crick already know when they were trying to determine the structure of DNA?
The number of _____.
a. purines is always larger than the number of pyrimidines
b. pyrimidines is always larger than purines
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a. the two atoms sharing electrons are equally electronegative
b. one of the atoms sharing electrons is more electronegative than the other atom
c. carbon is one of the two atoms sharing electrons
d. one of the atoms has absorbed more energy than the other atom
e. the two atoms sharing electrons are the same element - ANSWERb. one of the atoms sharing
electrons is more electronegative than the other atom-n(T1) Why are hydrocarbons insoluble in water?
a. The majority of their bonds are nonpolar covalent carbon-to-hydrogen linkages
b. The majority of their bonds are polar covalent carbon-to-hydrogen linkages
c. They are hydrophilic
d. They exhibit considerable molecular complexity and diversity
e. They are less dense than water - ANSWERa. The majority of their bonds are nonpolar covalent
carbon-to-hydrogen linkages-n(T1) Which of the following is NOT a function of proteins?
a. movement activity
b. catalytic activity
c. transport activity
d. defense activity
e. ribosome activity - ANSWERe. ribosome activity-n(T1) Which of the following occurs when a covalent
bond forms?
a. Electrons in valence shells are transferred from one atom to another
,b. Electrons in valence shells are shared between atoms
c. Partial charges on polar molecules interact
d. Nonpolar molecules are pushed together by surrounded water molecules - ANSWERb. Electrons in
valence shells are shared between atoms-n(T1) At which level of protein structure are interactions
between the side chains (R-groups) most important?
a. primary
b. secondary
c. tertiary
d. quaternary
e. primary, secondary, tertiary, and quaternary - ANSWERc. tertiary-n(T1) You disrupt all hydrogen
bonds in a protein. What level of structure will be preserved?
a. primary structure
b. secondary structure
c. tertiary structure
d. quaternary structure - ANSWERa. primary structure-n(T1) Of the following, which is a good working
definition of a gene?
a. any particular sequence of DNA or RNA
b. a DNA subunit that codes for a single complete protein
c. a nucleic acid sequence that encodes a trait
d. a sequence of nucleic acid that encodes one or more functional RNA molecules
e. a discrete unit of hereditary information that consists of a sequence of amino acids - ANSWERd. a
sequence of nucleic acid that encodes one or more functional RNA molecules-n(T1) Transcription
continues until:
a. all bases in the DNA are copied
b. a terminator sequence is encountered
,c. a stop codon is encountered
d. a ribosome pulls RNA polymerase off the DNA.
e. a transcription factor signals the end of the gene - ANSWERb. a terminator sequence in encountered-
n(T1) If a DNA sample were composed of 10% thymine, what would be the percentage of guanine?
a. 80
b. 40
c. 20
d. 10
e. It is impossible to tell from the information given - ANSWERb. 40-n(T1) Which of the following is TRUE
of DNA?
a. Successive nucleotides in a strand are connected by hydrogen bonds
b. A purine always forms a complementary base pair with a pyrimidine
c. A phosphate group in a nucleotide is attached to the 3- carbon in ribose
d. The percentage of the purine A always equals the percentage of the purine G
e. It is used by ribosomes for translation - ANSWERb. A purine always forms a complementary base pair
with a pyrimidine-n(T1) In transcription, the energy to attach each successive ribonucleotide to the
growing RNA chain comes from:
a. the RNA polymerase itself
b. cleavage/breakage of the high-energy phosphate bonds of the incoming nucleotide
c. cleavage/breakage of the high-energy phosphate bonds of the growing mRNA molecule
d. cleavage/breakage of the 3' hydroxyl group on the ribose of the incoming nucleotide
e. a ribosome - ANSWERb. cleavage/breakage of the high-energy phosphate bonds on the incoming
nucleotide-n(T1) In the process of transcription, _____.
a. DNA is replicated
, b. RNA is synthesized
c. proteins are synthesized
d. mRNA attaches to ribosomes - ANSWERb. RNA is synthesized-n(T1) How does the simple primary and
secondary structure of DNA hold the information needed to code for the many features of the
multicellular organisms?
a. The hydrogen bonding amonf backbone constituents carries coded information
b. The base sequence of DNA carries the information needed to code for RNA molecules
c. The width of the double helix changes at each gene due to differences in hydrogen bonds
d. The amino acids that make up the DNA molecule contain the information needed to make cellular
proteins - ANSWERb. The base sequence of DNA carries the information needed to code for RNA
molecules-n(T1) Nucleic acids have a definite polarity, or directionality. Stated another way, one end of
the molecule is different from the other end. How are these ends described?
a. One end has an -OH group on the 2' carbon; the other end has a phosphate group on the 2' carbon
b. One end has a nitrogenous base; the other end lacks a nitrogenous base
c. One end is at the 3' carbon; the other end is at the 5' carbon
d. One end has one phosphate group; the other end has three phosphate groups - ANSWERc. One end is
at the 3' carbon; the other end is at the 5' carbon-n(T1) Which of the following best describes DNA's
secondary structure?
a. beta-pleated sheet
b. two parallel helical strands
c. turn-loop-turn
d. two antiparallel helical strands - ANSWERd. two antiparallel helical strands-n(T1) Which of the
following did Watson and Crick already know when they were trying to determine the structure of DNA?
The number of _____.
a. purines is always larger than the number of pyrimidines
b. pyrimidines is always larger than purines
