Molecular Biology Final Exam UPDATED
ACTUAL Questions and CORRECT
Answers
Which of the following is NOT a stabilizing force for the structure and stability of double-
stranded nucleic acids? - CORRECT ANSWER - disulfide bonds
A reaction can only occur spontaneously when the free-energy change is - CORRECT
ANSWER - negative
Which of the following statements regarding protein domains is NOT true? - CORRECT
ANSWER - Proteins are only comprised of one protein domain
Which of the following statements about DNA and RNA is TRUE? - CORRECT
ANSWER - All portions of the genome are replicated but only discrete genes are
transcribed
Which of the following is NOT a hydrophobic amino acid - CORRECT ANSWER - lysine
How did Brownell and Allis detect the activity of histone acetyl transferase? - CORRECT
ANSWER - HAT was detected by the transfer of [3H]acetyl group to histones in specific
region of activity gel
Which of the follwoing statements best describes the basic mechanism by which boundary
elements carry out their function? - CORRECT ANSWER - Specific proteins bind the
boundary element sequence and physically block the formation of heterochromatin
Prokaryotes use DNA methylation to __________ while many eukaryotes use DNA methylation
to ______. - CORRECT ANSWER - distinguish newly synthesized DNA and protect their
DNA; silence genes
,Which of the following statements regarding the use of catalysts is FALSE? - CORRECT
ANSWER - Catalysts increase the number of reactions that can happen spontaneously
The HP1 protein plays a key role in formation of heterochromatin in mammals by: - CORRECT
ANSWER - binding to methylated histone H3.
The association of DNA with histones - CORRECT ANSWER - can lead to higher order
packing of the DNA
Histone modification has the biggest impact on - CORRECT ANSWER - the accessibility
of DNA to cellular enzymes
The major secondary structures of proteins are - CORRECT ANSWER - alpha helix and
beta sheet
Although all protein structures are unique, there are common structural building blocks that are
referred to as regular secondary structures. Some have alpha helices, some have beta sheets, and
still others have a combination of both. What makes it possible for proteins to have these
common structural elements? - CORRECT ANSWER - hydrogen bonds along the protein
backbone
Hydrogen bonds in proteins - CORRECT ANSWER - are individually weak but
collectively strong and contribute to the formation of higher order structure
Which histone protein attaches to DNA strands between nucleosomes - CORRECT
ANSWER - H1
Each nucleotide in DNA and RNA has an aromatic base. What is the principal force that keeps
the bases in a nucleic polymer from interacting with water? - CORRECT ANSWER -
hydrophobic interactions
,Methylation and acetylation are common changes made to histone H3, and the specific
combination of these changes is sometimes referred to as the histone code. Which of the
following patterns will probably lead to gene silencing? - CORRECT ANSWER - lysine 9
methylation
Intergenic DNA is best decribed as - CORRECT ANSWER - DNA between genes that
does not code for a protein but may have regulatory function
Which of the following statements is FALSE regarding chromatin immunoprecipitation (ChIP) -
CORRECT ANSWER - ChIP-seq data enables the detection of sequence of the protein
domain that is bound to DNA
Base pairing depends on - CORRECT ANSWER - hydrogen bonds; there are 2 bonds
between A and T and 3 bonds between C and G
Which amino acid side chain may be modified by the addition of a sugar molecule? - CORRECT
ANSWER - asparagine
The N-terminal tail of histone H3 can be extensively modified, and depending on the number,
location, and combination of these modifications, these changes may promote the formation of
heterochromatin. What is the result of heterochromatin formation? - CORRECT
ANSWER - gene silencing
Which of the following statements about amino acids is TRUE? - CORRECT ANSWER -
All amino acids contain an NH3+ and a COO- group
What is the effect of the repressor complex - CORRECT ANSWER - N terminal tails of
histones are deacetylated resulting in repression of gene expression
Which statement is true regarding negative supercoiled DNA? - CORRECT ANSWER -
Since negative supecoiled DNA is under-rotated, it allows for easier strand separation durng
replication and transcription
, Why are lysine and arginine amino acids present in all four common core histone proteins? -
CORRECT ANSWER - They have positively charged side chain residues and allow the
histone to interract with DNA's negatively charged backbone
What are the complementary base pairs to the following nucleotides. 5'GTCCATATTGC 3' -
CORRECT ANSWER - 3'CAGGTATAACG5'
The active site of an enzyme differs from an antibody-antigen binding site in that the enzyme
active site - CORRECT ANSWER - catalyzes a chemical reaction
All of the following are considered "weak" interactions in proteins, except: - CORRECT
ANSWER - peptide bonds
The process by which enzymes accelerate the rate of a biochemical reaction is called ____. -
CORRECT ANSWER - catalysis
How are telomeric repeats added to the ends of chromosomes without a template for DNA
synthesis? - CORRECT ANSWER - the enzyme telomerase has an RNA subunit
containing the template for synthesizing the repeats
The difference between RNA and DNA is the presence of a: - CORRECT ANSWER - 2'
hydroxyl group on the ribose sugar in RNA
Model organisms are important in the study of biological processes. Which statement is FALSE
regarding model organisms? - CORRECT ANSWER - Two well studied genetically
tractable model organisms are Danio rario and Xenopus laevis
Which type of covalent bond is important for linking cysteine residues located at various places
in a polypeptide? - CORRECT ANSWER - disulfide bond
Which type of amino acid would be most likely found on the interior of a DNA binding protein -
CORRECT ANSWER - hydrophobic
ACTUAL Questions and CORRECT
Answers
Which of the following is NOT a stabilizing force for the structure and stability of double-
stranded nucleic acids? - CORRECT ANSWER - disulfide bonds
A reaction can only occur spontaneously when the free-energy change is - CORRECT
ANSWER - negative
Which of the following statements regarding protein domains is NOT true? - CORRECT
ANSWER - Proteins are only comprised of one protein domain
Which of the following statements about DNA and RNA is TRUE? - CORRECT
ANSWER - All portions of the genome are replicated but only discrete genes are
transcribed
Which of the following is NOT a hydrophobic amino acid - CORRECT ANSWER - lysine
How did Brownell and Allis detect the activity of histone acetyl transferase? - CORRECT
ANSWER - HAT was detected by the transfer of [3H]acetyl group to histones in specific
region of activity gel
Which of the follwoing statements best describes the basic mechanism by which boundary
elements carry out their function? - CORRECT ANSWER - Specific proteins bind the
boundary element sequence and physically block the formation of heterochromatin
Prokaryotes use DNA methylation to __________ while many eukaryotes use DNA methylation
to ______. - CORRECT ANSWER - distinguish newly synthesized DNA and protect their
DNA; silence genes
,Which of the following statements regarding the use of catalysts is FALSE? - CORRECT
ANSWER - Catalysts increase the number of reactions that can happen spontaneously
The HP1 protein plays a key role in formation of heterochromatin in mammals by: - CORRECT
ANSWER - binding to methylated histone H3.
The association of DNA with histones - CORRECT ANSWER - can lead to higher order
packing of the DNA
Histone modification has the biggest impact on - CORRECT ANSWER - the accessibility
of DNA to cellular enzymes
The major secondary structures of proteins are - CORRECT ANSWER - alpha helix and
beta sheet
Although all protein structures are unique, there are common structural building blocks that are
referred to as regular secondary structures. Some have alpha helices, some have beta sheets, and
still others have a combination of both. What makes it possible for proteins to have these
common structural elements? - CORRECT ANSWER - hydrogen bonds along the protein
backbone
Hydrogen bonds in proteins - CORRECT ANSWER - are individually weak but
collectively strong and contribute to the formation of higher order structure
Which histone protein attaches to DNA strands between nucleosomes - CORRECT
ANSWER - H1
Each nucleotide in DNA and RNA has an aromatic base. What is the principal force that keeps
the bases in a nucleic polymer from interacting with water? - CORRECT ANSWER -
hydrophobic interactions
,Methylation and acetylation are common changes made to histone H3, and the specific
combination of these changes is sometimes referred to as the histone code. Which of the
following patterns will probably lead to gene silencing? - CORRECT ANSWER - lysine 9
methylation
Intergenic DNA is best decribed as - CORRECT ANSWER - DNA between genes that
does not code for a protein but may have regulatory function
Which of the following statements is FALSE regarding chromatin immunoprecipitation (ChIP) -
CORRECT ANSWER - ChIP-seq data enables the detection of sequence of the protein
domain that is bound to DNA
Base pairing depends on - CORRECT ANSWER - hydrogen bonds; there are 2 bonds
between A and T and 3 bonds between C and G
Which amino acid side chain may be modified by the addition of a sugar molecule? - CORRECT
ANSWER - asparagine
The N-terminal tail of histone H3 can be extensively modified, and depending on the number,
location, and combination of these modifications, these changes may promote the formation of
heterochromatin. What is the result of heterochromatin formation? - CORRECT
ANSWER - gene silencing
Which of the following statements about amino acids is TRUE? - CORRECT ANSWER -
All amino acids contain an NH3+ and a COO- group
What is the effect of the repressor complex - CORRECT ANSWER - N terminal tails of
histones are deacetylated resulting in repression of gene expression
Which statement is true regarding negative supercoiled DNA? - CORRECT ANSWER -
Since negative supecoiled DNA is under-rotated, it allows for easier strand separation durng
replication and transcription
, Why are lysine and arginine amino acids present in all four common core histone proteins? -
CORRECT ANSWER - They have positively charged side chain residues and allow the
histone to interract with DNA's negatively charged backbone
What are the complementary base pairs to the following nucleotides. 5'GTCCATATTGC 3' -
CORRECT ANSWER - 3'CAGGTATAACG5'
The active site of an enzyme differs from an antibody-antigen binding site in that the enzyme
active site - CORRECT ANSWER - catalyzes a chemical reaction
All of the following are considered "weak" interactions in proteins, except: - CORRECT
ANSWER - peptide bonds
The process by which enzymes accelerate the rate of a biochemical reaction is called ____. -
CORRECT ANSWER - catalysis
How are telomeric repeats added to the ends of chromosomes without a template for DNA
synthesis? - CORRECT ANSWER - the enzyme telomerase has an RNA subunit
containing the template for synthesizing the repeats
The difference between RNA and DNA is the presence of a: - CORRECT ANSWER - 2'
hydroxyl group on the ribose sugar in RNA
Model organisms are important in the study of biological processes. Which statement is FALSE
regarding model organisms? - CORRECT ANSWER - Two well studied genetically
tractable model organisms are Danio rario and Xenopus laevis
Which type of covalent bond is important for linking cysteine residues located at various places
in a polypeptide? - CORRECT ANSWER - disulfide bond
Which type of amino acid would be most likely found on the interior of a DNA binding protein -
CORRECT ANSWER - hydrophobic
