Molecular Biology Exam test quizzes
and answers graded A+
Which of the following is NOT a stabilizing force for the structure and stability of double-stranded
nucleic acids? - ANS✅✅disulfide bonds
A reaction can only occur spontaneously when the free-energy change is - ANS✅✅negative
Which of the following statements regarding protein domains is NOT true? - ANS✅✅Proteins are
only comprised of one protein domain
Which of the following statements about DNA and RNA is TRUE? - ANS✅✅All portions of the
genome are replicated but only discrete genes are transcribed
Which of the following is NOT a hydrophobic amino acid - ANS✅✅lysine
How did Brownell and Allis detect the activity of histone acetyl transferase? - ANS✅✅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? - ANS✅✅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
______. - ANS✅✅distinguish newly synthesized DNA and protect their DNA; silence genes
Which of the following statements regarding the use of catalysts is FALSE? - ANS✅✅Catalysts
increase the number of reactions that can happen spontaneously
The HP1 protein plays a key role in formation of heterochromatin in mammals by: -
ANS✅✅binding to methylated histone H3.
The association of DNA with histones - ANS✅✅can lead to higher order packing of the DNA
,Histone modification has the biggest impact on - ANS✅✅the accessibility of DNA to cellular
enzymes
The major secondary structures of proteins are - ANS✅✅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? - ANS✅✅hydrogen bonds along the protein backbone
Hydrogen bonds in proteins - ANS✅✅are individually weak but collectively strong and contribute
to the formation of higher order structure
Which histone protein attaches to DNA strands between nucleosomes - ANS✅✅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? - ANS✅✅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? - ANS✅✅lysine 9 methylation
Intergenic DNA is best decribed as - ANS✅✅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) -
ANS✅✅ChIP-seq data enables the detection of sequence of the protein domain that is bound to
DNA
Base pairing depends on - ANS✅✅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? -
ANS✅✅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? - ANS✅✅gene silencing
Which of the following statements about amino acids is TRUE? - ANS✅✅All amino acids contain an
NH3+ and a COO- group
What is the effect of the repressor complex - ANS✅✅N terminal tails of histones are deacetylated
resulting in repression of gene expression
Which statement is true regarding negative supercoiled DNA? - ANS✅✅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? -
ANS✅✅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' -
ANS✅✅3'CAGGTATAACG5'
The active site of an enzyme differs from an antibody-antigen binding site in that the enzyme active
site - ANS✅✅catalyzes a chemical reaction
All of the following are considered "weak" interactions in proteins, except: - ANS✅✅peptide bonds
The process by which enzymes accelerate the rate of a biochemical reaction is called ____. -
ANS✅✅catalysis
How are telomeric repeats added to the ends of chromosomes without a template for DNA
synthesis? - ANS✅✅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: - ANS✅✅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? - ANS✅✅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? - ANS✅✅disulfide bond
Which type of amino acid would be most likely found on the interior of a DNA binding protein -
ANS✅✅hydrophobic
Chromatin refers to the form of genomic DNA found in the nucleus of interphase cells. Actively
transcribed genes are likely to be found in which kind of chromatin? - ANS✅✅euchromatin
What is the defining feature of all centromeres? - ANS✅✅All centromeres contain nucleosomes
with a characteristic H3 histone variant.
what is the function of the nucleolus? - ANS✅✅it is the site for synthesis and processing of rRNA
molecules
Which of the following is NOT a type of non-covalent interaction? - ANS✅✅Phosphate bond
Which of the following amino acids causes kinks in the protein backbone and may disrupt secondary
structure? - ANS✅✅proline
How is DNA packaged in the bacterial cell (E. coli, for example)? - ANS✅✅It is package by small
basic proteins to bend DNA, then supercoiled by DNA gyrase and DNA topoisomerase.
Bromodomains bind - ANS✅✅acetylated lysine
Which type of bonds link the individual nucleotides together in DNA? - ANS✅✅phosphodiester
Which statement about nucleic acids is TRUE? - ANS✅✅The polarity of a DNA strand results from
the polarity of the nucleotide subunits.
and answers graded A+
Which of the following is NOT a stabilizing force for the structure and stability of double-stranded
nucleic acids? - ANS✅✅disulfide bonds
A reaction can only occur spontaneously when the free-energy change is - ANS✅✅negative
Which of the following statements regarding protein domains is NOT true? - ANS✅✅Proteins are
only comprised of one protein domain
Which of the following statements about DNA and RNA is TRUE? - ANS✅✅All portions of the
genome are replicated but only discrete genes are transcribed
Which of the following is NOT a hydrophobic amino acid - ANS✅✅lysine
How did Brownell and Allis detect the activity of histone acetyl transferase? - ANS✅✅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? - ANS✅✅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
______. - ANS✅✅distinguish newly synthesized DNA and protect their DNA; silence genes
Which of the following statements regarding the use of catalysts is FALSE? - ANS✅✅Catalysts
increase the number of reactions that can happen spontaneously
The HP1 protein plays a key role in formation of heterochromatin in mammals by: -
ANS✅✅binding to methylated histone H3.
The association of DNA with histones - ANS✅✅can lead to higher order packing of the DNA
,Histone modification has the biggest impact on - ANS✅✅the accessibility of DNA to cellular
enzymes
The major secondary structures of proteins are - ANS✅✅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? - ANS✅✅hydrogen bonds along the protein backbone
Hydrogen bonds in proteins - ANS✅✅are individually weak but collectively strong and contribute
to the formation of higher order structure
Which histone protein attaches to DNA strands between nucleosomes - ANS✅✅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? - ANS✅✅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? - ANS✅✅lysine 9 methylation
Intergenic DNA is best decribed as - ANS✅✅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) -
ANS✅✅ChIP-seq data enables the detection of sequence of the protein domain that is bound to
DNA
Base pairing depends on - ANS✅✅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? -
ANS✅✅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? - ANS✅✅gene silencing
Which of the following statements about amino acids is TRUE? - ANS✅✅All amino acids contain an
NH3+ and a COO- group
What is the effect of the repressor complex - ANS✅✅N terminal tails of histones are deacetylated
resulting in repression of gene expression
Which statement is true regarding negative supercoiled DNA? - ANS✅✅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? -
ANS✅✅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' -
ANS✅✅3'CAGGTATAACG5'
The active site of an enzyme differs from an antibody-antigen binding site in that the enzyme active
site - ANS✅✅catalyzes a chemical reaction
All of the following are considered "weak" interactions in proteins, except: - ANS✅✅peptide bonds
The process by which enzymes accelerate the rate of a biochemical reaction is called ____. -
ANS✅✅catalysis
How are telomeric repeats added to the ends of chromosomes without a template for DNA
synthesis? - ANS✅✅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: - ANS✅✅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? - ANS✅✅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? - ANS✅✅disulfide bond
Which type of amino acid would be most likely found on the interior of a DNA binding protein -
ANS✅✅hydrophobic
Chromatin refers to the form of genomic DNA found in the nucleus of interphase cells. Actively
transcribed genes are likely to be found in which kind of chromatin? - ANS✅✅euchromatin
What is the defining feature of all centromeres? - ANS✅✅All centromeres contain nucleosomes
with a characteristic H3 histone variant.
what is the function of the nucleolus? - ANS✅✅it is the site for synthesis and processing of rRNA
molecules
Which of the following is NOT a type of non-covalent interaction? - ANS✅✅Phosphate bond
Which of the following amino acids causes kinks in the protein backbone and may disrupt secondary
structure? - ANS✅✅proline
How is DNA packaged in the bacterial cell (E. coli, for example)? - ANS✅✅It is package by small
basic proteins to bend DNA, then supercoiled by DNA gyrase and DNA topoisomerase.
Bromodomains bind - ANS✅✅acetylated lysine
Which type of bonds link the individual nucleotides together in DNA? - ANS✅✅phosphodiester
Which statement about nucleic acids is TRUE? - ANS✅✅The polarity of a DNA strand results from
the polarity of the nucleotide subunits.
