CMB 311 Exam 1 Practice Questions With
Correct Answers
What are the six classes of enzymes that we learned? - ANSWER 1)
oxidoreductases
2) transferases
3) hydrolases
4) lyases
5) isomerases
6) ligases
What is competitive inhibition of enzyme? How to overcome competitive
inhibition? - ANSWER A competitive inhibitor I binds to E and competes with
S for the active site. This lowers the apparent affinity of E for S (and raises
apparent Km).
Inhibition can be overcome by adding more S
What are the 3 characteristics that distinguish living creatures from
inanimate objects? - ANSWER They are chemically complex and highly
organized. They interact and use energy (nutrients) from the environment
and export end products of metabolism (like CO2 exhale). THey have the
capacity to precisely self-replicate and self-assemble.
Transfer of electrons (hydride ions or H atoms) - ANSWER oxidoreductases
Group transfer reactions - ANSWER Transferases
,Hydrolysis reactions - ANSWER Hydrolases
Remove groups, leaving double bonds, or conversely add groups to double
bonds - ANSWER Lyases
Transfer of groups within molecules; yield isomeric forms - ANSWER
Isomerases
Gibbs free energy equation - ANSWER Δ G = Δ H - TΔ S
What does the competitive inhibition change? Km or Vmax? - ANSWER Vmax
is not affected
The apparent Km is increased by the factor α
Formation of C-C, C-S, C-O and C-N bonds by condensation - ANSWER
Ligases
How does a competitive inhibition change the hyperbolic rate-substrate
curve and the double-reciprocal curve, respectively? - ANSWER Competitive
inhibition changes the hyperbolic rate-substrate curve by increasing the Km
and making the curve more linear at the start.
Competitive inhibition changes the double-reciprocal curve by increasing the
angle of the line from the x-axis
What do "catalytic residues" do? - ANSWER Catalytic residues may make
covalent bonds with the substrate or transition state intermediate, but these
are always temporary
A site on an enzyme where substrates bind and undergo chemical reaction -
ANSWER active site
What are functional groups? - ANSWER the components of organic
,molecules that are most commonly involved in chemical reactions
How do Motrin (Ibuprofen) and Naprosen reduce pain and inflammation?
What enzyme do they bind? - ANSWER Arachidonic acid (AA) is an
unsaturated C20 fatty acid that is converted (by adding 2 molecules of O2)
into prostaglandins that mediate pain and inflammation.
The enzyme that catalyze this reactions is Cyclo-oxygenase (COX).
Motrin and naprosen are competitive inhibitors of COX.
Is a substance whose shape mimics that of a transition state
Can be used to uncover a catalytic mechanism
Can sometimes act as enzyme inhibitors - ANSWER transition state analog
Proteins can be classified by shape, what are the 2 types? What are their
properties? - ANSWER 1) globular proteins: soluble and spherical
2) fibrous proteins: insoluble and rod-like
What are the four mechanisms of enzymatic catalysis that we learned? -
ANSWER -Positioning of substrate(s)
-Proton transfer (acid-base catalysis)
-Covalent catalysis (bond cleavage/formation with the enzyme)
-Metal ion catalysis (ionic interactions, oxidation/reduction)
What is uncompetitive inhibition of enzyme? - ANSWER Binds to ES (it may
distort the active site or otherwise prevent conversion of ES to E + P).
If I mention the name of one amino acid, do you know which category it
belongs to and its three-letter and one-letter abbreviation? Make sure you
, are able to tell. Also know the amino acid structures and properties. (Be able
to recognize the amino acid if you see the structure or its properties). -
ANSWER
What are the examples of acid-base catalysis and covalent catalysis,
respectively? - ANSWER acid-base catalysis:
-Ribonuclease A
-Chymotrypsin
covalent catalysis
What does the uncompetitive inhibition change? Km or Vmax? - ANSWER ESI
complex is non-productive so Vmax is lowered.
The ES reduction increases the E-S affinity (decreases Km).
What are the general characters of red blood cells? Why is carbonic
anhydrase important? - ANSWER 1) Are "bags of the protein hemoglobin"
plus the enzyme "carbonic anhydrase*" (and many other proteins)
2) Contains NO nucleus and therefore can not divide
3) Are made in the bone marrow from a precursor cell
Live in the blood for 120 d when they are taken up by the macrophages in
the "reticuloendothelial system" (or "mononuclear phagocytic system",
which includes spleen, liver, bone marrow, lymph nodes).
4) Unload the O2 from hemoglobin in capillaries of all tissues
How does an uncompetitive inhibition change the hyperbolic rate-substrate
curve and the double-reciprocal curve, respectively? - ANSWER Uncompetitve
inhibition changes the hyperbolic rate-substrate curve by decreasing Km and
Correct Answers
What are the six classes of enzymes that we learned? - ANSWER 1)
oxidoreductases
2) transferases
3) hydrolases
4) lyases
5) isomerases
6) ligases
What is competitive inhibition of enzyme? How to overcome competitive
inhibition? - ANSWER A competitive inhibitor I binds to E and competes with
S for the active site. This lowers the apparent affinity of E for S (and raises
apparent Km).
Inhibition can be overcome by adding more S
What are the 3 characteristics that distinguish living creatures from
inanimate objects? - ANSWER They are chemically complex and highly
organized. They interact and use energy (nutrients) from the environment
and export end products of metabolism (like CO2 exhale). THey have the
capacity to precisely self-replicate and self-assemble.
Transfer of electrons (hydride ions or H atoms) - ANSWER oxidoreductases
Group transfer reactions - ANSWER Transferases
,Hydrolysis reactions - ANSWER Hydrolases
Remove groups, leaving double bonds, or conversely add groups to double
bonds - ANSWER Lyases
Transfer of groups within molecules; yield isomeric forms - ANSWER
Isomerases
Gibbs free energy equation - ANSWER Δ G = Δ H - TΔ S
What does the competitive inhibition change? Km or Vmax? - ANSWER Vmax
is not affected
The apparent Km is increased by the factor α
Formation of C-C, C-S, C-O and C-N bonds by condensation - ANSWER
Ligases
How does a competitive inhibition change the hyperbolic rate-substrate
curve and the double-reciprocal curve, respectively? - ANSWER Competitive
inhibition changes the hyperbolic rate-substrate curve by increasing the Km
and making the curve more linear at the start.
Competitive inhibition changes the double-reciprocal curve by increasing the
angle of the line from the x-axis
What do "catalytic residues" do? - ANSWER Catalytic residues may make
covalent bonds with the substrate or transition state intermediate, but these
are always temporary
A site on an enzyme where substrates bind and undergo chemical reaction -
ANSWER active site
What are functional groups? - ANSWER the components of organic
,molecules that are most commonly involved in chemical reactions
How do Motrin (Ibuprofen) and Naprosen reduce pain and inflammation?
What enzyme do they bind? - ANSWER Arachidonic acid (AA) is an
unsaturated C20 fatty acid that is converted (by adding 2 molecules of O2)
into prostaglandins that mediate pain and inflammation.
The enzyme that catalyze this reactions is Cyclo-oxygenase (COX).
Motrin and naprosen are competitive inhibitors of COX.
Is a substance whose shape mimics that of a transition state
Can be used to uncover a catalytic mechanism
Can sometimes act as enzyme inhibitors - ANSWER transition state analog
Proteins can be classified by shape, what are the 2 types? What are their
properties? - ANSWER 1) globular proteins: soluble and spherical
2) fibrous proteins: insoluble and rod-like
What are the four mechanisms of enzymatic catalysis that we learned? -
ANSWER -Positioning of substrate(s)
-Proton transfer (acid-base catalysis)
-Covalent catalysis (bond cleavage/formation with the enzyme)
-Metal ion catalysis (ionic interactions, oxidation/reduction)
What is uncompetitive inhibition of enzyme? - ANSWER Binds to ES (it may
distort the active site or otherwise prevent conversion of ES to E + P).
If I mention the name of one amino acid, do you know which category it
belongs to and its three-letter and one-letter abbreviation? Make sure you
, are able to tell. Also know the amino acid structures and properties. (Be able
to recognize the amino acid if you see the structure or its properties). -
ANSWER
What are the examples of acid-base catalysis and covalent catalysis,
respectively? - ANSWER acid-base catalysis:
-Ribonuclease A
-Chymotrypsin
covalent catalysis
What does the uncompetitive inhibition change? Km or Vmax? - ANSWER ESI
complex is non-productive so Vmax is lowered.
The ES reduction increases the E-S affinity (decreases Km).
What are the general characters of red blood cells? Why is carbonic
anhydrase important? - ANSWER 1) Are "bags of the protein hemoglobin"
plus the enzyme "carbonic anhydrase*" (and many other proteins)
2) Contains NO nucleus and therefore can not divide
3) Are made in the bone marrow from a precursor cell
Live in the blood for 120 d when they are taken up by the macrophages in
the "reticuloendothelial system" (or "mononuclear phagocytic system",
which includes spleen, liver, bone marrow, lymph nodes).
4) Unload the O2 from hemoglobin in capillaries of all tissues
How does an uncompetitive inhibition change the hyperbolic rate-substrate
curve and the double-reciprocal curve, respectively? - ANSWER Uncompetitve
inhibition changes the hyperbolic rate-substrate curve by decreasing Km and
