USABO EVALUATION TEST QUESTIONS AND
ANSWERS SET A+
✔✔NH₃ - ✔✔Ammonia, a biproduct of the GDH reaction during deamination which is
highly toxic and water soluble, thus able to move out of the mitochodrial matrix easily.
✔✔Ketone bodies - ✔✔A combination of two acetyl CoA molecules which is used as
fuel by the heart and brain.
✔✔Serine - ✔✔This compound is one of the naturally occurring proteinogenic amino
acids. Its codons are UCU, UCC, UCA, UCG, AGU and AGC. Only the L-stereoisomer
appears naturally in proteins. It is not essential to the human diet, since it is synthesized
in the body from other metabolites, including glycine. It was first obtained from silk
protein, a particularly rich source, in 1865. Its name is derived from the Latin for silk,
sericum.
✔✔Alanine - ✔✔Alanine (abbreviated as Ala or A)[2] is an α-amino acid with the
chemical formula CH3CH(NH2)COOH. It can be synthesized from the pyruvate
intermediate of the TCA cycle. The L-isomer is one of the 22 proteinogenic amino acids,
i.e., the building blocks of proteins. Its codons are GCU, GCC, GCA, and GCG. It is
classified as a nonpolar amino acid. L-Alanine is second only to leucine in rate of
occurrence, accounting for 7.8% of the primary structure in a sample of 1,150
proteins.D-Alanine occurs in bacterial cell walls and in some peptide antibiotics.
✔✔Aspartate - ✔✔The precursor to several amino acids, including four that are
essential for humans: methionine, threonine, isoleucine, and lysine. The conversion of
aspartate to these other amino acids begins with reduction of aspartate to its
"semialdehyde,"O₂CCH(NH₂)CH₂CHO.
Asparagine is derived from aspartate via transamidation. Aspartate (the conjugate base
of aspartic acid) stimulates NMDA receptors, though not as strongly as the amino acid
neurotransmitter glutamate does.
,✔✔White 'glycolytic' fibres - ✔✔Type II fibers are white due to the absence of myoglobin
and a reliance on glycolytic enzymes. These fibers are efficient for short bursts of speed
and power and use both oxidative metabolism and anaerobic metabolism depending on
the particular sub-type. These fibers are quicker to fatigue.
✔✔Red 'oxidative' fibres - ✔✔Type I fibers appear red due to the presence of the
oxygen binding protein myoglobin. These fibers are suited for endurance and are slow
to fatigue because they use oxidative metabolism to generate ATP.
✔✔Compartmentation - ✔✔Cellular compartments in cell biology comprise all closed
parts within a cell, usually surrounded by a single or double lipid layer membrane. Most
organelles are compartments like mitochondria, chloroplasts (in photosynthetic
organisms), peroxisomes, lysosomes, the endoplasmic reticulum, the cell nucleus or the
Golgi apparatus. Smaller elements like vesicles, and sometimes even microtubules can
also be counted as compartments.
✔✔Metabolic channelling - ✔✔Substrate channeling is when the intermediary metabolic
product of one enzyme is passed directly to another enzyme or active site without being
released into solution. When several consecutive enzymes of a metabolic pathway
channel substrates between themselves, this is called a metabolon. Channeling can
make a metabolic pathway more rapid and efficient than it would be if the enzymes
were randomly distributed in the cytosol, or prevent the release of unstable
intermediates. It can also protect an intermediate from being consumed by competing
reactions catalyzed by other enzymes.
✔✔Metabolic flux - ✔✔Flux, or metabolic flux is the rate of turnover of molecules
through a metabolic pathway. Flux is regulated by the enzymes involved in a pathway.
Within cells, regulation of flux is vital for all metabolic pathways to regulate the
metabolic pathway's activity under different conditions. Flux is therefore of great interest
in metabolic network modelling, where it is analysed via flux balance analysis.
✔✔GLUT4 - ✔✔Glucose transporter type 4, is a protein that in humans is encoded by
the GLUT4 gene. It is the insulin-regulated glucose transporter found in adipose tissues
and striated muscle (skeletal and cardiac) that is responsible for insulin-regulated
glucose translocation into the cell. This protein is expressed primarily in muscle and fat
cells, the major tissues in the body that respond to insulinThe specific membrane
transporter protein upregulated by insulin when glucose is in high concentrations in the
blood.
✔✔Oxidative phosphorylation - ✔✔This is the process by which electrons are
transferred from electron donors to electron acceptors such as oxygen, in redox
reactions. These redox reactions release energy, which is used to form ATP. In
eukaryotes, these redox reactions are carried out by a series of protein complexes
within mitochondria, whereas, in prokaryotes, these proteins are located in the cells'
inner membranes. These linked sets of proteins are called electron transport chains. In
,eukaryotes, five main protein complexes are involved, whereas in prokaryotes many
different enzymes are present, using a variety of electron donors and acceptors.
✔✔LDH reaction - ✔✔This is the reaction which interconverts pyruvate and lactate with
concomitant interconversion of NADH and NAD+ catalysed by lactate dehydrogenase. It
converts pyruvate, the final product of glycolysis, to lactate when oxygen is absent or in
short supply, and it performs the reverse reaction during the Cori cycle in the liver. At
high concentrations of lactate, the enzyme exhibits feedback inhibition, and the rate of
conversion of pyruvate to lactate is decreased.
✔✔Substrate-level phosphorylation - ✔✔An enzyme catalysed process in which which
ATP is made by transferring phosphate directly onto ADP from a phsphporylated carbon
intermediate in the cytosol. This is the only way for cells without mitochondria to make
ATP, such as red blood cells and the lens of the eye. It is also a main contributor of ATP
for high energy cells such as those of the immune system.
✔✔Electrochemical gradient - ✔✔A gradient which provides an imbalance of charge
between the inside and outside of the cell, a key requirement in the production of ATP
brought about by the electron transport chain.
✔✔ATP synthase - ✔✔An important enzyme, a large structure which makes up 15% of
the protein in the inner mitochondrial membrane, that provides energy for the cell to use
through the synthesis of adenosine triphosphate (ATP). ATP is the most commonly
used "energy currency" of cells from most organisms. It is formed from adenosine
diphosphate (ADP) and inorganic phosphate (Pi) which releases energy. This energy is
often in the form of protium or H+, moving down an electrochemical gradient, such as
from the lumen into the stroma of chloroplasts or from the inter-membrane space into
the matrix in mitochondria.
✔✔Chemiosmotic coupling - ✔✔The process that couples or links the electron transport
chain to ATP synthes. Chemiosmosis is described as one of the mechanisms by which
ATP is produced. As the electrons pass through the electron transport chain, energy is
released, which is used to establish a proton gradient across a selectively-permeable
membrane. The proton gradient drives the protons (hydrogen ions) to move down the
gradient, releasing the energy that is in turn captured in the terminal phosphate bonds
of ATP.
✔✔The c ring - ✔✔The tiny electrically driven motor found in ATP synthase.
✔✔The gamma rod - ✔✔The centrally located crank shaft found in ATP synthase
thought to be involved in the conversion of an energy gradient in to elastic energy.
✔✔Cytochromes - ✔✔Membrane-bound hemoproteins that contain heme groups and
carry out electron transport.
, They are found either as monomeric proteins (e.g., cytochrome c) or as subunits of
bigger enzymatic complexes that catalyze redox reactions. They are found in the
mitochondrial inner membrane and endoplasmic reticulum of eukaryotes, in the
chloroplasts of plants, in photosynthetic microorganisms, and in bacteria.
✔✔Fe-S protein - ✔✔Best known for their role in the oxidation-reduction reactions of
mitochondrial electron transport. Both Complex I and Complex II of oxidative
phosphorylation have multiple Fe-S clusters. They have many other functions including
catalysis as illustrated by aconitase, generation of radicals as illustrated by SAM-
dependent enzymes, and as sulfur donors in the biosynthesis of lipoic acid and biotin.
Additionally some Fe-S proteins regulate gene expression. Fe-S proteins are vulnerable
to attack by biogenic nitric oxide.
✔✔Respiratory complexes - ✔✔The name given to 'bunched together' electron carriers
of the electron transport chain.
✔✔Mobile carriers - ✔✔Two such carriers are found in the ETC in the form of
ubiquinone (or Q) and the protein cytochrome c.
✔✔Respiratory control - ✔✔When electron carriers of the ETC 'sense' the slowing down
of ATP synthase, due to full sotkc of ATP in the mitochondria, they too slow down the
transfer of electrons, thus automatically conserving fuel when ATP is plentiful.
✔✔Uncoupler - ✔✔Any compound that increases the proton permiability of the inner
mitochondrial membrane and hence severes the link between electron transport and
ATP synthesis. Two example are thyroxine and brown adipose tissue.
✔✔Resolving Power - ✔✔Image's clarity; limited by the shortest wavelength of radiation
used for imaging
✔✔Cytology - ✔✔Study of cell structure
✔✔Cell Fractionation - ✔✔Separate major organelles so individual functions can be
observed; brought about with centrifuge
✔✔Supernatant - ✔✔Where lighter particles from centrifuge reside; the heavier ones
reside in the pellet
✔✔Nuclear Lamina - ✔✔The protein filaments which maintain the shape of the nucleus
✔✔hydroxyl group - ✔✔Alcohols (specific names usually end in -ol)
✔✔carbonyl group - ✔✔Ketones- If the carbonyl group is within a carbon skeleton.
Aldehydes- If the carbonyl group is at the end of the carbon skeleton.
ANSWERS SET A+
✔✔NH₃ - ✔✔Ammonia, a biproduct of the GDH reaction during deamination which is
highly toxic and water soluble, thus able to move out of the mitochodrial matrix easily.
✔✔Ketone bodies - ✔✔A combination of two acetyl CoA molecules which is used as
fuel by the heart and brain.
✔✔Serine - ✔✔This compound is one of the naturally occurring proteinogenic amino
acids. Its codons are UCU, UCC, UCA, UCG, AGU and AGC. Only the L-stereoisomer
appears naturally in proteins. It is not essential to the human diet, since it is synthesized
in the body from other metabolites, including glycine. It was first obtained from silk
protein, a particularly rich source, in 1865. Its name is derived from the Latin for silk,
sericum.
✔✔Alanine - ✔✔Alanine (abbreviated as Ala or A)[2] is an α-amino acid with the
chemical formula CH3CH(NH2)COOH. It can be synthesized from the pyruvate
intermediate of the TCA cycle. The L-isomer is one of the 22 proteinogenic amino acids,
i.e., the building blocks of proteins. Its codons are GCU, GCC, GCA, and GCG. It is
classified as a nonpolar amino acid. L-Alanine is second only to leucine in rate of
occurrence, accounting for 7.8% of the primary structure in a sample of 1,150
proteins.D-Alanine occurs in bacterial cell walls and in some peptide antibiotics.
✔✔Aspartate - ✔✔The precursor to several amino acids, including four that are
essential for humans: methionine, threonine, isoleucine, and lysine. The conversion of
aspartate to these other amino acids begins with reduction of aspartate to its
"semialdehyde,"O₂CCH(NH₂)CH₂CHO.
Asparagine is derived from aspartate via transamidation. Aspartate (the conjugate base
of aspartic acid) stimulates NMDA receptors, though not as strongly as the amino acid
neurotransmitter glutamate does.
,✔✔White 'glycolytic' fibres - ✔✔Type II fibers are white due to the absence of myoglobin
and a reliance on glycolytic enzymes. These fibers are efficient for short bursts of speed
and power and use both oxidative metabolism and anaerobic metabolism depending on
the particular sub-type. These fibers are quicker to fatigue.
✔✔Red 'oxidative' fibres - ✔✔Type I fibers appear red due to the presence of the
oxygen binding protein myoglobin. These fibers are suited for endurance and are slow
to fatigue because they use oxidative metabolism to generate ATP.
✔✔Compartmentation - ✔✔Cellular compartments in cell biology comprise all closed
parts within a cell, usually surrounded by a single or double lipid layer membrane. Most
organelles are compartments like mitochondria, chloroplasts (in photosynthetic
organisms), peroxisomes, lysosomes, the endoplasmic reticulum, the cell nucleus or the
Golgi apparatus. Smaller elements like vesicles, and sometimes even microtubules can
also be counted as compartments.
✔✔Metabolic channelling - ✔✔Substrate channeling is when the intermediary metabolic
product of one enzyme is passed directly to another enzyme or active site without being
released into solution. When several consecutive enzymes of a metabolic pathway
channel substrates between themselves, this is called a metabolon. Channeling can
make a metabolic pathway more rapid and efficient than it would be if the enzymes
were randomly distributed in the cytosol, or prevent the release of unstable
intermediates. It can also protect an intermediate from being consumed by competing
reactions catalyzed by other enzymes.
✔✔Metabolic flux - ✔✔Flux, or metabolic flux is the rate of turnover of molecules
through a metabolic pathway. Flux is regulated by the enzymes involved in a pathway.
Within cells, regulation of flux is vital for all metabolic pathways to regulate the
metabolic pathway's activity under different conditions. Flux is therefore of great interest
in metabolic network modelling, where it is analysed via flux balance analysis.
✔✔GLUT4 - ✔✔Glucose transporter type 4, is a protein that in humans is encoded by
the GLUT4 gene. It is the insulin-regulated glucose transporter found in adipose tissues
and striated muscle (skeletal and cardiac) that is responsible for insulin-regulated
glucose translocation into the cell. This protein is expressed primarily in muscle and fat
cells, the major tissues in the body that respond to insulinThe specific membrane
transporter protein upregulated by insulin when glucose is in high concentrations in the
blood.
✔✔Oxidative phosphorylation - ✔✔This is the process by which electrons are
transferred from electron donors to electron acceptors such as oxygen, in redox
reactions. These redox reactions release energy, which is used to form ATP. In
eukaryotes, these redox reactions are carried out by a series of protein complexes
within mitochondria, whereas, in prokaryotes, these proteins are located in the cells'
inner membranes. These linked sets of proteins are called electron transport chains. In
,eukaryotes, five main protein complexes are involved, whereas in prokaryotes many
different enzymes are present, using a variety of electron donors and acceptors.
✔✔LDH reaction - ✔✔This is the reaction which interconverts pyruvate and lactate with
concomitant interconversion of NADH and NAD+ catalysed by lactate dehydrogenase. It
converts pyruvate, the final product of glycolysis, to lactate when oxygen is absent or in
short supply, and it performs the reverse reaction during the Cori cycle in the liver. At
high concentrations of lactate, the enzyme exhibits feedback inhibition, and the rate of
conversion of pyruvate to lactate is decreased.
✔✔Substrate-level phosphorylation - ✔✔An enzyme catalysed process in which which
ATP is made by transferring phosphate directly onto ADP from a phsphporylated carbon
intermediate in the cytosol. This is the only way for cells without mitochondria to make
ATP, such as red blood cells and the lens of the eye. It is also a main contributor of ATP
for high energy cells such as those of the immune system.
✔✔Electrochemical gradient - ✔✔A gradient which provides an imbalance of charge
between the inside and outside of the cell, a key requirement in the production of ATP
brought about by the electron transport chain.
✔✔ATP synthase - ✔✔An important enzyme, a large structure which makes up 15% of
the protein in the inner mitochondrial membrane, that provides energy for the cell to use
through the synthesis of adenosine triphosphate (ATP). ATP is the most commonly
used "energy currency" of cells from most organisms. It is formed from adenosine
diphosphate (ADP) and inorganic phosphate (Pi) which releases energy. This energy is
often in the form of protium or H+, moving down an electrochemical gradient, such as
from the lumen into the stroma of chloroplasts or from the inter-membrane space into
the matrix in mitochondria.
✔✔Chemiosmotic coupling - ✔✔The process that couples or links the electron transport
chain to ATP synthes. Chemiosmosis is described as one of the mechanisms by which
ATP is produced. As the electrons pass through the electron transport chain, energy is
released, which is used to establish a proton gradient across a selectively-permeable
membrane. The proton gradient drives the protons (hydrogen ions) to move down the
gradient, releasing the energy that is in turn captured in the terminal phosphate bonds
of ATP.
✔✔The c ring - ✔✔The tiny electrically driven motor found in ATP synthase.
✔✔The gamma rod - ✔✔The centrally located crank shaft found in ATP synthase
thought to be involved in the conversion of an energy gradient in to elastic energy.
✔✔Cytochromes - ✔✔Membrane-bound hemoproteins that contain heme groups and
carry out electron transport.
, They are found either as monomeric proteins (e.g., cytochrome c) or as subunits of
bigger enzymatic complexes that catalyze redox reactions. They are found in the
mitochondrial inner membrane and endoplasmic reticulum of eukaryotes, in the
chloroplasts of plants, in photosynthetic microorganisms, and in bacteria.
✔✔Fe-S protein - ✔✔Best known for their role in the oxidation-reduction reactions of
mitochondrial electron transport. Both Complex I and Complex II of oxidative
phosphorylation have multiple Fe-S clusters. They have many other functions including
catalysis as illustrated by aconitase, generation of radicals as illustrated by SAM-
dependent enzymes, and as sulfur donors in the biosynthesis of lipoic acid and biotin.
Additionally some Fe-S proteins regulate gene expression. Fe-S proteins are vulnerable
to attack by biogenic nitric oxide.
✔✔Respiratory complexes - ✔✔The name given to 'bunched together' electron carriers
of the electron transport chain.
✔✔Mobile carriers - ✔✔Two such carriers are found in the ETC in the form of
ubiquinone (or Q) and the protein cytochrome c.
✔✔Respiratory control - ✔✔When electron carriers of the ETC 'sense' the slowing down
of ATP synthase, due to full sotkc of ATP in the mitochondria, they too slow down the
transfer of electrons, thus automatically conserving fuel when ATP is plentiful.
✔✔Uncoupler - ✔✔Any compound that increases the proton permiability of the inner
mitochondrial membrane and hence severes the link between electron transport and
ATP synthesis. Two example are thyroxine and brown adipose tissue.
✔✔Resolving Power - ✔✔Image's clarity; limited by the shortest wavelength of radiation
used for imaging
✔✔Cytology - ✔✔Study of cell structure
✔✔Cell Fractionation - ✔✔Separate major organelles so individual functions can be
observed; brought about with centrifuge
✔✔Supernatant - ✔✔Where lighter particles from centrifuge reside; the heavier ones
reside in the pellet
✔✔Nuclear Lamina - ✔✔The protein filaments which maintain the shape of the nucleus
✔✔hydroxyl group - ✔✔Alcohols (specific names usually end in -ol)
✔✔carbonyl group - ✔✔Ketones- If the carbonyl group is within a carbon skeleton.
Aldehydes- If the carbonyl group is at the end of the carbon skeleton.
