BBMB-301 Test questions and Answers for
Final studying (Iowa State)
Which class of biopolymers is responsible for separating distinct aqueous
compartments within Eukaryotic cells?
Lipids
The ______ is surrounded by a double membrane and produces approximately
90% of the energy, in the form of ATP, used by a typical living cell
Mitochondrion
T or F: The central dogma in biochemistry describes the flow of information from
RNA to DNA to polypeptide to functional protein
False: its DNA to RNA to Polypeptide to Protein
using the Henderson-Hasselbalch equation, calculate the pH of the solution of a
weak acid (pKa 4.0) when the concentration of the conjugate base is 10 times
higher than the concentration of the acid.
5
what type of weak interaction is driven by the entropy effect
Hydrophobic interactions
Describe the term pKa
pKa is the pH at which an acid is 50% dissassociated
What amino acid has a pKa near neutral pH
Histidine
What happens to an amino acid at pH 7?
NH2 groups are protonated while COOH groups are deprotonated
Which amino acid is a polar aromatic?
Tyrosine
What is the charge of the peptide asp-gly-arg-his at pH 8?
0
What is a peptide bond
the bond between the NH2 and COOH groups
What weak interactions can be involved in stabilization of both secondary and
tertiary structures of proteins?
Hydrogen bonds
Describe the process of protein denaturation
Proteins loose their secondary and tertiary structures do to the disruption of weak
interactions and sulfide bonds
The tertiary structure of a protein is what?
Arrangements of secondary structure elements in three dimensional space to form a
compact folded structure
What does gel-filtration and SDS-Page do?
proteins are separated according to their size
what type of chromatography would you use to separate asp-gly-asp-ala-glu-his-
pro and ser-gly-asn-ala-gly-his-pro
Anion exchange chromatography
Describe the steps of protein sequencing by Edman degredation
, Polypeptide is labeled with phenyl isothioxyanate, binds to free amino groups, peptide
bond labeled amino acid is hydrolyzed, labeled amino acid is analyze by capillary
electrophoresis
T or F Genome and proteome both reflect the fixed characteristics of a particular
cell and vary only between different species and organisims
False it can be different inside of a single organisim
A reaction can occur spontaneously only if free energy of reaction (delta G) is
Negative
How does an enzyme catalyze the reactions?
Lowers activation energy
what does ligase do?
joins two molecules using ATP
Use the Michaelis-Menten equation calculate the value of Vmax and the reaction
which has V0=10mM/min when [S] is equal to 4 Km
12.5
A critical feature of the Michaelis-Menten model of enzyme catalysis is
the formation of an Enzyme-substrate complex
T or F The turnover number of an enzyme (kcat) is the rate at which an enzyme
saturated with a substrate converts this substrate to a product and is dependent
on the concentration of enzymes and describes the relative speed of a reaction
True
How is a Keq value spontaneous?
positive
Describe the mechanism of hydrolysis catalyzed by chymotrypsin
an acid-base covalent catalysis that generates an unstable tetrahedral intermediate
stabilized by weak interactions with R groups in oxyanion holes
What type of enzyme inhibition has two parallel times on a double reciprocal plot
Uncompetitive
T or F enzyme that uses the mechanism of proximity forces two substrates into
an appropriate three-dimensional arrangement using numerous weak interactions
between amino acids in an active site and substrates
True
The kinetic study shows that enzymatic reaction in the presence of an inhibitor
increased Km but didn't change Vmax. What can be concluded about how this
inhibitor binds to the enzyme
It binds to the active site
What do we call enzymes that do not follow the Michaelis-Menten model, use
cooperative mode of action, and can be present in the tense and relaxed state?
Allosteric Enzymes
T or F hemoglobin is called oxy hemoglobin when it is the most stable state T
with O2 bound in all subunits
False
How does 2,3-bisphosphoglycerate regulate hemoglobin
The allosteric regulator interacts with the positive charges on the two beta sub-units of
the Hemoglobin and stabilizes the T state; This allosteric regulator interacts with
Final studying (Iowa State)
Which class of biopolymers is responsible for separating distinct aqueous
compartments within Eukaryotic cells?
Lipids
The ______ is surrounded by a double membrane and produces approximately
90% of the energy, in the form of ATP, used by a typical living cell
Mitochondrion
T or F: The central dogma in biochemistry describes the flow of information from
RNA to DNA to polypeptide to functional protein
False: its DNA to RNA to Polypeptide to Protein
using the Henderson-Hasselbalch equation, calculate the pH of the solution of a
weak acid (pKa 4.0) when the concentration of the conjugate base is 10 times
higher than the concentration of the acid.
5
what type of weak interaction is driven by the entropy effect
Hydrophobic interactions
Describe the term pKa
pKa is the pH at which an acid is 50% dissassociated
What amino acid has a pKa near neutral pH
Histidine
What happens to an amino acid at pH 7?
NH2 groups are protonated while COOH groups are deprotonated
Which amino acid is a polar aromatic?
Tyrosine
What is the charge of the peptide asp-gly-arg-his at pH 8?
0
What is a peptide bond
the bond between the NH2 and COOH groups
What weak interactions can be involved in stabilization of both secondary and
tertiary structures of proteins?
Hydrogen bonds
Describe the process of protein denaturation
Proteins loose their secondary and tertiary structures do to the disruption of weak
interactions and sulfide bonds
The tertiary structure of a protein is what?
Arrangements of secondary structure elements in three dimensional space to form a
compact folded structure
What does gel-filtration and SDS-Page do?
proteins are separated according to their size
what type of chromatography would you use to separate asp-gly-asp-ala-glu-his-
pro and ser-gly-asn-ala-gly-his-pro
Anion exchange chromatography
Describe the steps of protein sequencing by Edman degredation
, Polypeptide is labeled with phenyl isothioxyanate, binds to free amino groups, peptide
bond labeled amino acid is hydrolyzed, labeled amino acid is analyze by capillary
electrophoresis
T or F Genome and proteome both reflect the fixed characteristics of a particular
cell and vary only between different species and organisims
False it can be different inside of a single organisim
A reaction can occur spontaneously only if free energy of reaction (delta G) is
Negative
How does an enzyme catalyze the reactions?
Lowers activation energy
what does ligase do?
joins two molecules using ATP
Use the Michaelis-Menten equation calculate the value of Vmax and the reaction
which has V0=10mM/min when [S] is equal to 4 Km
12.5
A critical feature of the Michaelis-Menten model of enzyme catalysis is
the formation of an Enzyme-substrate complex
T or F The turnover number of an enzyme (kcat) is the rate at which an enzyme
saturated with a substrate converts this substrate to a product and is dependent
on the concentration of enzymes and describes the relative speed of a reaction
True
How is a Keq value spontaneous?
positive
Describe the mechanism of hydrolysis catalyzed by chymotrypsin
an acid-base covalent catalysis that generates an unstable tetrahedral intermediate
stabilized by weak interactions with R groups in oxyanion holes
What type of enzyme inhibition has two parallel times on a double reciprocal plot
Uncompetitive
T or F enzyme that uses the mechanism of proximity forces two substrates into
an appropriate three-dimensional arrangement using numerous weak interactions
between amino acids in an active site and substrates
True
The kinetic study shows that enzymatic reaction in the presence of an inhibitor
increased Km but didn't change Vmax. What can be concluded about how this
inhibitor binds to the enzyme
It binds to the active site
What do we call enzymes that do not follow the Michaelis-Menten model, use
cooperative mode of action, and can be present in the tense and relaxed state?
Allosteric Enzymes
T or F hemoglobin is called oxy hemoglobin when it is the most stable state T
with O2 bound in all subunits
False
How does 2,3-bisphosphoglycerate regulate hemoglobin
The allosteric regulator interacts with the positive charges on the two beta sub-units of
the Hemoglobin and stabilizes the T state; This allosteric regulator interacts with
