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Biochem II Exam 3 practice questions

Terms in this set (277)

The hormone glucagon induces the hydrolysis of ___________ glycogen during periods of _____________-.
hepatic; hypoglycemia
The intracellular agent cAMP is formed in hepatocytes by the reaction: ATP + H2O --> cAMP + PPi; that is catalyzed by the enzyme _________; and cAMP is hydrolyzed to AMP by the reaction: cAMP + H2O --> AMP; that is catalyzed by the enzyme _________.
adenylyl cyclase; phosphodiesterase
As a result of the appearance of the metabolite F-2,6-bisphosphate in an important substrate cycle the rate of the pathway called ___________ is increased and the rate of the pathway called ___________ is decreased.
glycolysis; gluoneogenesis
The hydrolysis of SKM glycogen has no impact on blood sugar concentration because SKM cells lack the enzymatic ability to ___________.
hydrolyze G-6-P
In a normal feeding starving cycle, sources of blood sugar include dietary glucose, ___________
hepatic glycogenolysis, and hepatic gluconeogenesis
After around 24 hours of fasting, all but about ________ of a person's liver glycogen is gone.
5%
The pathway for FA biosynthesis begins with a reaction between carbon dioxide and _________ to produce ___________.
acetyl CoA; malonyl CoA
During the reaction sequence that demonstrates the use of glucose as a source of carbon atoms for fatty acid synthesis, one notes that pyruvate is decarboxylated to yield __________, carboxylated to yield ________, and the two products condense to give citrate
acetyl CoA; OAA
Anytime acetyl CoA appears in the cellular cytosol, it is assumed that the two carbon metabolite is formed in the mitochondrial matrix and crossed the inner mitochondrial membrane in the form of ______.
citrate
The synthesis of lipids like TAGs and various types of phosphatides require the metabolite glycerol that is usually formed by reducing the glycolytic component _________.
DHAP
Cholesterol synthesis usually starts with the condensation of several molecules of __________.
acetyl CoA
Cholesterol is considered to be a starting material for the agents
steroid hormones and bile salts
Which of the following substances are usually found in the core of a lipoprotein?
TAGs and cholesterol esters
VLDLs are formed in ______ and transport ______ away from that site.
hepatocytes; endogenous TAGs
Cholesterol esters are formed by a reaction between cholesterol and lecithin that is catalyzed by the apolipoprotein _________, a component of the lipoprotein ________.
LCAT; HDL
During periods of fasting induced hypoglycemia, the hormone ________ induces a release of FFAs from ________.
glucagon; adipocytes
During starvation, carbohydrate catabolism is limited as _____ is inhibited by acetyl CoA that is derived from _______.
pyruvate dehydrogenase; beta oxidation
Although the cells oxidize FAs to carbon dioxide during periods of starvation, the liver oxidizes the FAs to _________, that is then converted into ________ in the hepatocyte
acetyl CoA; ketone bodies
Which of the following types of cells do not oxidize FAs to CO2, even during periods of starvation
neurons of the CNS and RBCs
One of the functions of folic acid is to recover the essential AA methionine by __________
adding a methyl group to homocysteine
Which of the following amino acids donates at least one of the nitrogen atoms during the de novo synthesis of a purine nucleus?
glutamine
Which of the following B complex vitamins is involved in the addition of a methyl group to the pyramidine nucleus during the synthesis of the agent thymine?
folic acid
Which of the following contains a purine nucleus?
uric acid
Iron is a component of all of the choices below except
apoferritin (component of ferritin, hemoglobin, transferritin, and hemosiderin)
Hepatic clearance of ethyl alcohol inhibits gluconeogensis because ________, a glucoeogenetic precursor, is often converted into lactate in order to insure a supply of __________ that is used as the oxidizing agent to convert the alcohol into acetate
pyruvate; NAD+
Cholesterol biosynthesis is controlled at the point in the process where this intermediate metabolite is produced.
mevalonic acid
Skeletal muscle glycogenolysis is instigated under the influence of this hormone.
epinephrine
This metabolite is the substrate for the enzyme phosphodiesterase
cAMP
One of the FAs regarded as essential is called this
linoleic acid
iron is absorbed from the intestinal lumen when it reacts with this agent
apoferritin
T/F: The biosynthesis of a FA requires extensive use of the agent NADP+
false
T/F: SKM cells cannot contribute glucose from the hydrolysis of glycogen to the blood plasma because of a lack of the enzyme glucose-6-phosphatase in that type of cell
true
T/F: Hepatic clearance of ethyl alcohol causes the intracellular ratio NAD+/NADH to increase
false
T/F: A lack of cellular B-100 receptor sites usually leads to increased plasma concentrations of LDLs
true
T/F: Even though methionine is an essential AA, humans can prepare this agent by methylating homocysteine
true
Which of the following hormones, or sets of hormones, enable(s) the hydrolysis of SKM glycogen?
epinephrine
The hydrolysis of liver glycogen under the influence of glucagon can result in an increase in blood plasma glucose concentration because of the action of the enzyme _______ found in hepatocytes
glucose-6-phosphatase
Which of the following enzymes is specifically activated by increasing concentrations of cAMP in hepatocytes
protein kinase A
Malonyl CoA, the three carbon metabolite used to elongate a growing FA, is synthesized by reacting ____ and ___
acetyl CoA and HCO3-
The reducing agent used for fatty biosynthesis is generated when _________ is oxidized by the pathway called _________.
pyruvate; glycolysis
The pyruvate-citrate cycle shows that when glucose is used as a carbon source for the biosynthesis of FAs, _______ of the carbons in glucose are incorporated into a growing FA.
4
During FA synthesis, pyruvate if carboxylated to yield _______ and decarboxylated to yield ______
OAA; acetyl CoA
The metabolite ________, that is readily available from the pathway called ________, can be reduced to L-glycerol phosphate to provide the three carbon component of lipids like TAGs
DHAP; glycolysis
What combination of reactions would be required to convert the FA: 16:1 DELTA 9; into the FA: 20:2 DELTA 9 DELTA 13? Note: for the purposes of this equation, D means desaturation and E means elongation
E-E-D
The FA _________ is regarded as essential because the human organism cannot produce a carbon-carbon double bond having a 'delta' number greater than ______
palmitate; 9
Which of the following sets of metabolites are components of the agent bile
cholesterol, cholic acid, and water
Which of the following uses of metabolites are synthesized using cholesterol as a starting material?
corticosteroids and androgens
Chylomicrons carry ______ TAGs to adipocytes where the TAGs are converted to their components by a series of reactions catalyzed by the enzyme _______
exogenous; LCAT
In the event of a genetic problem that results in the production of mutant and ineffective B-100 receptors, one would expect a(n) ______ in the plasma concentration of the lipoprotein ______
increase; LDL
HDL, also called 'good cholesterol', aids in the elimination of plasma cholesterol by converting it into ______.
cholesterol esters
The FAs mobilized from adipocytes are converted into ______ in SKM cells and into ______ in hepatocytes
CO2; ketone bodies
As humans switch from carbs to FAs as fuel, the newly available FAs help to limit carb oxidation by supplying acetyl CoA which in turn inhibits the enzyme ______ preventing glucose from being catabolized beyond ______
pyruvate dehydrogenase; pyruvate
Aspartate is non-essential AA because it can be synthesized in vivo by conducting an aminotransferase reaction between ______
glutamate and OAA
In the de novo synthesis of pyrimidines, the first pyrimidine to form is ______ and this agent is then modified to form either _______
uracil; thymine or cytosine
Some segments of the population demonstrate a genetic predisposition to the condition called gout (hyperuricemia), that can result in a failure of the enzyme phosphoribosylpyrophosphate synthase to respond to its normal allosteric inhibitor ______ that can lead to elevated plasma levels if uric acid.
ATP
The folic acid 'trap' is a description of a set of circumstances where the normal reaction sequence in which folic acid (tetrahydrofolate) supplies a methyl group to homocysteine to make methionine is stopped when a deficiency of the cofactor ______ prevents the above reaction step from happening and 'traps' folic acid as 5-methyltetrahydrofolate
cobalamin
Carbohydrates are used by adrenergic neurons to provide cytoplasmic ______ needed for the synthesis of the neurotransmitter ______ within the neuron
acetyl CoA; acetylcholine
Type II diabetes often results when plasma insulin fails to activate one or more of the 'secondary messengers' within cells such as ______ resulting in the glucose transporter called ______ to be unable to admit plasma glucose to the cell
SKM cells; GLUT 4
Normally speaking, iron can only be assimilated from the intestinal mucosal cells can supply the protein _______ to react with the iron to make the adduct called ______ that is retained within the mucosal cells
apoferritin; ferritin
During periods in which the liver is clearing large amounts if ethyl alcohol, hepatic gluconeogenesis is limited because the normal starting material for gluconeogenesis, ______, is converted to _______ in order to prepare the cofactor NAD+ for alcohol dehydrogenase
pyruvate; lactate
This catecholamine hormone triggers the hydrolysis of both SKM and liver glycogen
epinephrine
The synthesis of this pyrimidine requires tetrahydrofolate to supply a methyl group to its structure
thymine
Both chylomicrons and this type of lipoprotein require apolopoprotein C-II for them to function
VLDLs
Acetyl CoA is moved from the mitochondrial matrix to the cytosol in the form of this metabolite
citrate
The extracellular concentration of glucose is diminished by the action of this hormone
insulin
T/F: Fat soluble vitamins move from the intestinal lumen to the liver without going through the hepatic portal vein
true
T/F: The agents that are characterized as essential FAs are all polyunsaturated
true
T/F: The carboxylation of acetyl CoA yields either malonyl CoA or acetoacetyl CoA
false
T/F: The synthesis of purines is regulated by the intracellular concentration of the allosteric modulators UTP and GTP for the enzyme phosphoribosylpyrophosphate synthase
false
T/F: Iron can only be lost by the human organism via the intestinal tract as a fecal component
true
Glucagon is a _____ hormone that effects a(n) _____ in blood sugar concentration by reacting with receptor sites found in the plasma membrane of ______
polypeptide; increase; hepatocytes
The mechanism that ultimately leads to the hydrolysis of liver glycogen involves a series of reactions involving the enzyme squence: ______ NOTE: gly. phos. = glycogen phosphorylation; gly. phos. kin. = glycogen phosphorylase kinase; phosdi. = phosphodiesterase; and cAMP stim. = cAMP stimulated protein kinase
cAMP stim.-gly. phos. kin.-gly. phos.
Glucagon induced hydrolysis of SKM glycogen will have no impact on blood sugar concentrations because the enzyme _______ is not found in the SKM cells
glucose-6-phosphatase
A study of timing of the use of various glucose sources in a normal feeding-starving cycle shows that the onset of hepatic gluconeogenesis occurs about _____ hours after a feeding event
4-6
FA biosynthesis is _______ and takes place in the cellular _______
reductive; cytosol
During the biosynthesis of a FA, each time the growing FA is condensed with the three carbon metabolite malonyl CoA, the FA increases in length by _____ carbons and _____ millimoles of reducing agents are consumed before the next condensation process happens
2;2
The reducing agent NADPH is oxidized to NADP+ during FA synthesis and the NADP+ is reduced to NADPH during the course of the pathway called _____
pentose pathway
The mechanism for FA biosynthesis using carbohydrates as starting materials shows that to prepare one millimole of the FA 16:0, _______ millimoles of pyruvate must be prepared from the carbohydrate and by the time the FA is completed, a total of _____ millimoles of CO2 will have been produced along with the FA
8;8
The agent acetyl CoA is produced in the cytosol during FA synthesis as the metabolite ________ moves from the matrix to the cytosol
citrate
If one subjects the FA 16:0 to the following: elongation; desaturation; elongation; the fatty acid ______ will result
20:1 DELTA 11
When lipids such as TAGs are prepared, the three carbons found in the 'glycerol' portion of the lipid are supplied by the metabolite ______, which is a component of the pathway called _____
dihydroxyacetone-P; glycolysis
The sterol 'nucleus' is found in all of the compounds listed below except ______.
mevalonic acid (a cholesterol synthesis intermediate)
The entero-hepatic cycle shows that cholesterol can be lost from the human organism via _____.
fecal elimination
The components of lipoprotines called apolipoproteins are best classified as ______
polypeptides
Which of the following sets of lipoproteins is normally associated with the transport of TAGs?
chylomicrons and VLDLs
Which of the following lipoproteins will be most likely to appear in abnormally high concentrations in the plasma as a result of a genetic defect that produces a mutation in B-100 receptors in SKM cells?
LDL
Fat mobilization is instigated by _______ and depends on the interaction of _______ with the enzyme ______ to initiate a series of reactions in adipocytes that result in the hydrolysis of TAGs
hypoglycemia; glucagon; adenyl cyclase
The FFAs provided by adipocytes during fat mobilization are converted to _____ in SKM cells and to _____ in hepatocytes
CO2 and H20; ketone bodies
During fat mobilization, carbohydrate catabolism in SKM cells is largely prevented as the metabolite acetyl CoA, produced from _______, inhibits the enzyme _______.
beta oxidation; pyruvate dehydrogenase
Most of the carbon atoms used for hepatic gluconeogenesis are moved from ______ to the liver in the form of ______
SKM cells; alanine
It is important that early starvation induced gluconeogenesis takes place in the liver because only the liver ______ at this point in the normal feeding-starving cycle
hydrolyzes G-6-P to glucose
A dietary deficiency of vitamin B12 can lead to _____ within the human organism
excess homocysteine
Which of the following sets of AA donates nitrogen atoms to the synthetic pathway used for purine synthesis?
glutamine and glycine
Most of the glucose required for the functioning of an adrenergic neuron if used to ______
supply acetyl CoA for acetylcholine synthesis
The absorption of iron form the intestinal lumen if dependent on the availability of ______
apoferritin in the intestinal lumen
Plasma cholesterol is esterified under the influence of this apolipoprotein
LCAT
When a methyl group is removed from methionine, this agent is left behind
homocysteine
Regulation of the biosynthetic pathway for cholesterol is accomplished by limiting the production of this metabolite
mevalonate
This metabolite is synthesized in both adipocytes and hepatocytes under the influence of the extracellular agent glucagon
cAMP
coenzyme A is replaced as an acyl group carrier by this metabolite during FA biosynthesis
acyl carrier protein
T/F: Gout occurs when excess urea is converted into uric acid and the uric acid collects and precipitates in synovial fluids and cartilage tissue
false
T/F: the human organism is capable of locating a carbon-carbon double bond anywhere in a FA by using the appropriate desaturation reaction
false
T/F: Both cholesterol and cholesterol esters appear in the hydrophobic core of low density lipoproteins (LDLs)
false
T/F: Most of the cholesterol that is synthesized in the human organism is made in the liver
true
T/F: one of the functions of insulin is to limit lipolysis in adipocytes
true
Insulin is a ______ hormone and is supplied by the _______ during periods of _______ blood sugar
polypeptide; pancreas; increasing
What is the sequence of enzymes involved in the glucagon inspired hydrolysis of liver glycogen? Note: gly. phos. = glycogen phosphorylase; gly. phos. kin. = glycogen phosphorylase kinase; cAMP stim. = cAMP stimulated protein kinase
cAMP stim.-gly. phos. kin.-gly. phos.
Which of the following enzymes is stimulated directly by the agent glucagon?
adenyl cyclase
How many millimoles of acetyl CoA are converted to malonyl CoA during the biosynthesis of a C-16 saturated FA?
7
Most of the reducing agent NADH, used during FA synthesis, is produced by the pathway called ________, during which the carbon atoms in __________ are oxidized to CO2
the 'shunt'; glucose
The pyruvarte-citrate cycle uses two reactions involving pyruvate: the decarboxylation of pyruvate to yield ______, and the carboxylation of pyruvate to yield _______.
acetyl CoA; OAA
When carbs are supplying the carbon for FA synthesis, ______ of the carb carbons that are used end up in the FA and _____ if the carb carbons that are used end up as carbon dioxide.
2/3; 1/3
If one were to start with the FA, 18:0, and subject it to an elongation reaction followed by a desaturation reaction, the result would be the FA _____.
20:1 DELTA 9
All TAGs and many phosphatides are produced by forming various FA esters of the metabolite _________, which is generated when either dihydroxyacetone-p or glyceraldehyde-3-p is reduced.
glycerol-p
Cholesterol is lost by a normal human organism via
the entero-hepatic cycle
The hepatic synthesis of cholesterol typically starts with ______ and is limited by ______
acetyl CoA; cholesterol
Which of the following sets of substances are typically found in the core of a lipoprotein
cholesterol esters and TAGs
Which of the following sets of lipoproteins is normally associated with the transport of TAGs
chylomicrons and VLDLs
Which of the following is activated by apolipoprotein C-II?
LPL
One of the functions of HDLs is to convert cholesterol into
cholesterol esters
Intracellular cholesterol restricts the uptake of additional cholesterol by that cell via a mechanism that involved the inhibition of the synthesis of ________
B-100 receptor sites
'Fat mobilization' is unlikely immediately after a meal because of the effect of the hormone _____ on the enzyme ______
insulin; adenyl cyclase
During periods of hypoglycemia, FFAs are converted into _______ at peripheral cell sites such as SKM and the kidney, and they are converted into ______ in hepatocytes
CO2; ketone bodies
When FAs or ketone bodies are being oxidized, the catabolism of glucose proceeds only as far as ______ due to the inhibition of the enzyme _____ by acetyl CoA
pyruvate; pyruvate dehydrogenase
During periods of hypoglycemia, the liver assimilates large amounts of alanine where the carbon atoms are made into ______ and the nitrogen is made into ________
CO2; Urea
A lack of cobalamin, as a result of a failure to absorb the agent from the intestinal tract or as a result of dietary shortfall, will often lead to systemic lack of ____
methionine
The failure of the allosteric sites on the enzyme phosphoribosylpyrophosphate synthase to react with _____ can leave the person susceptible to a condition known as hyperuricemia. Note: the synthase catalyzes the first step in the synthesis of inosinic acid, a purine.
ATP
The 'mucosal block' can be described as mechanism for regulating the uptake of iron by limiting the availability of the protein _______ in the intestinal mucosal cells
apoferritin
Hepatic clearance of ethyl alcohol inhibits gluconeogenesis by converting one of the normal gluconeogenetic precursors, pyruvate, into ______
lactate
How long would it take a 90 kg man to clear (hepatically) the amount of alcohol found in a 'fifth' (750 ml) of wine? The normal clearance rate for ethyl alcohol is 100mg/kg/hr and 24 proof wine contains about 96mg of alcohol per ml of wine.
8 hours
Cholesterol is stored in an intracellular context as this agent
cholesterol ester
During fasting, the concentration of this amino acid increases dramatically in blood plasma
alanine
The carboxylation of acetyl CoA yields this agent
malonyl CoA
This metabolite moves from the mitochondrial matrix to the cytosol during FA synthesis
citrate
T/F: FAs are catabolized by most cellular types except mature RBCs and neurons of the CNS
true
T/F: The hormone glucagon stimulates the enzyme phosphodiesterase which, in turn, catalyzes the hydrolysis of cAMP to generate AMP
false
T/F: Most of the cholesterol synthesized in the liver is used to form bile salts
true
T/F: Iron is stored as ferritin in both intestinal mucosal cells and the liver
true
T/F: Endogenous and exogenous TAGs are transported in a VLDL format
false
Fatty acid biosynthesis takes place in the cellular _______ and uses _______ as a starting material
cytoplasm; acetyl CoA
The systemic growth of a FA occurs as an existing FA undergoes a condensation reaction with ______.
malonyl SACP
The reaction sequence that takes place between condensation reactions during FA synthesis is _____.
reduction; dehydration; reduction
Complete the reaction: pyruvate + CO2 + ATP --> ______ ADP + Pi
OAA
The reducing agent NADPH, that is used extensively during FA biosynthesis, is derived from the _____
oxidation of G-6-P and decarboxylation of malate
The pyruvate-citrate cycle shows that when the organism is in a well fed state, most of the carbon used for FA biosynthesis comes from _____
carbs
In order to prepare FA; 20:2 DELTA 9, DELTA 13; from the FA 16:0, the reaction sequence should be _____ (Note: D=desaturation E=elongation)
D-E-E-D
Glycerol-3-phosphate, that is esterified with a series of FAs (fatty acyl CoA) to prepare endogenous TAGs, is derived from the ______
reduction of dihydroxyacetone-p
The entero-hepatic cycle shows a pathway for the daily loss (to the organism) of cholesterol and other sterols in the form of ____
bile components
When the biosynthesis of cholesterol is allosterically inhibited, the metabolite that starts to accumulate in the cell is _______
HMG CoA
Which of the following sets of lipoproteins is associated with the transport of TAGs
VLDL and chylomicron
Plasma cholesterol is converted into cholesterol esters by _____ with an assist from the apolipoprotein _______
HDL; LCAT
Intracellular cholesterol prevents the uptake of additional cholesterol by that cell by _______
inhibiting B-100 receptor synthesis
The agent known as 'bad cholesterol' is in reality the lipoprotein _______ which is noted for its function of transporting _______
LDL; cholesterol esters
Fat mobilization is instigated by _______
decreasing blood sugar
During starvation, one note limited carbohydrate oxidation in many types of cells as acetyl CoA, generated from Beta-oxidation and the catabolism of ketone bodies, inhibits the ______
decarboxylation of pyruvate
Which of the following amino acids is identified as the source of nitrogen used by the renal system to produce an ammonium ion that is excreted via the urine to maintain acid-base balance during a primary alkali deficit?
glutamine
A folic acid deficiency will generate an increase in the organism's daily requirement of the essential amino acid ______
methionine
Which of the sets of metabolites shown below requires the action of folic acid as a 'one-carbon carrier' during the biosynthesis of the component substances?
creatine and adenine
When there is a cobalamin shortage, the reaction: methylmalonyl CoA --> succinyl CoA; fails and methylmalonyl CoA becomes a substrate for FA synthase along with the enzyme's normal substrate, malonyl CoA. The result of this series of events is______
the synthesis of branched-chain FAs
When allosteric inhibition of the enzyme phosphoribosylpyrophosphatase synthase (PRPP synthase) fails, the result is uncontrolled synthesis of _________
inosinic acid
The uptake of iron from the intestinal lumen is dependent on the availability of _______ in the _______
apoferritin; intestinal mucosal cells
There is a difference between the nutritional requirement for iron and the physiological requirement for iron because of the _______
poor bioavailability of dietary iron
As the liver is clearing ethyl alcohol, the gluconeogenetic precursor _______ is reduced to _______ by NADH so that a supply of NAD+ is available to oxidize the alcohol
pyruvate; lactate
Continued alcohol use leads to a short term increase in plasma VLDL and, in the longer term, a fatty liver, because of an inability to oxidize FAs due to an intracellular lack of _______
NAD+
This reagent is an intermediate in the synthesis of cholesterol
HMG CoA
Of the various lipoproteins, this one has the highest percent (by weight) of TAGs
chylomicrons
Liver damage occurs when this iron containing protein accumulates there
hemosiderin
Discussions of 'intrinsic factor' revolve around this B-complex vitamin
cobalamin
All of the carbons in a biosynthesized FA had to be this agent at one time
acetyl CoA
T/F: The pyruvate-citrate cycle demonstrates that FAs can be synthesized from carbs
true
T/F: One's liver can store several years worth of cobalamin
true
T/F: the human organism is able to synthesize the FA 16:1 DELTA 13 from the FA 16:0
false
T/F: A genetic condition that leads to a failure of cells to produce apolipoprotein B-100 receptor sites could lead to elevated plasma levels of chylomicrons
false
T/F: The rate of ethyl alcohol clearance by the liver is initially very fast and diminishes as the alcohol is cleared
false
For the substrate cycle shown, where E1 and E2 are two different enzymes, the flux, which is initially ______, is changed to ______ when there is a 20% increase in the reaction rate for 'A-->B', and a 20% decrease in the reaction rate for 'B--A' (picture is on the answer side. oops)
75; 80
The important substrate cycle found in the glycolysis/gluconeogenesis pathway involves the enzyme _______ (glycolysis) and the enzyme F1,6 bisphosphatase (gluconeogensis), and the common modulator for this system is ________
hexokinase; F-2,6-P
The agent insulin is a _____ hormone that is produced by the ______ in response to _______ blood glucose concentration
polypeptide; pancreas; increasing
The hepatic hydrolysis of cAMP is catalyzed by the enzyme ______
cAMP stimulated protein kinase
Under normal circumstances, a person's liver glycogen will supply glucose to the blood plasma for about _____ hours after a feeding frenzy
30-36
Most of the acetyl CoA used during FA biosynthesis is first carboxylated to form _______, which is then used as an adduct to elongate the burgeoning FA by two carbon atoms
acetoacetyl CoA
FA biosynthesis takes place in the cellular _______ and requires the _______
mitochondria; reducing agent NADH
If a molecule of acetyl CoA made up of two radioactive carbon atoms (14C) is the initiating metabolite for the biosynthesis of the FA 16:0, what will the position of the two radioactive carbons be in the completed FA?
C-1; C-16
If a FA 16:0 undergoes the sequence: desaturation; elongation; desaturation; elongation; the resultant FA will be _______
20:2 DELTA 11 DELTA 13
The pyruvate-citrate cycle shows that the carbon atoms found in a biosynthesized FA are typically derived from glucose and ______ of the 'glucose' carbons end up in the FA with the remainder being made into _____
1/3; pyruvate
Acetyl CoA, that is used to synthesize a FA, is moved from the mitochondrial matrix to the cytosol in the form of the metabolite _______, that is made into acetyl CoA and OAA upon arrival in the cytosol
acetoacetate
The principal synthesis site for cholesterol is _______ and the starting material is _____
intestinal mucosal cells; glucose
Cholesterol is lost from the human organism via _____
oxidation to CO2
Which set of lipoproteins is normally associated with the transport of TAGs
chylomicrons and VLDLs
A genetically induced shortage of apolipoprotein C-II will produce a type of hyperlipoproteinemia characterized by the appearance of excessive amounts of _____ in the plasma
chylomicron
Excessive amounts of cholesterol within a cell cause the cell to minimize its uptake of additional cholesterol from the blood plasma by limiting the production of _______ within the cell
LPL receptors
Fat mobilization is instigated by the condition _______
ketoacidosis
The agent ______, producing during FA catabolism, tends to limit carbohydrate catabolism by inhibiting the enzyme ________
acetyl CoA; phosphofructokinase
The carbon atoms from any AA that is catabolized to pyruvate will be oxidized to carbon dioxide by entering the TCA cycle in the form of ________
acetyl CoA
Nitrogen is added to the urea cycle in the form of _____
aspartate and carbamoyl-p
If the hepatic enzyme arginosuccinase fails, one should expect an increase in the blood plasma concentration of ________ (Note: arginosuccinase catalyzes the reaction: arginosuccinate --> arginine + fumarate)
ammonia
Which of the following is a possible starting point for the gluconeogenetic pathway?
succinyl CoA
Gluconeogenesis relies on the malate shuttle to _____
move reducing power to the cytoplasm
Which of the following glycolytic reactions is not reversed during gluconeogenesis?
phosphoenolpyruvate + ADP --> pyruvate + ATP
Acyl functions are activated by converting them to esters of this pantothenate containing metabolite
coenzyme A
Sooner or later beta oxidation of an odd-carbon FA will produce this metabolite
propionyl CoA
The urea cycle uses this amino acid
ornithine
This pathway produces all of the carbon dioxide resulting from the catabolism of a FA
TCA cycle
This compound has a larger free energy of hydrolysis that ATP
creatine-p
T/F: During starvation, ketone bodies can be used as starting materials for gluconeogenesis
false
T/F: Beta oxidation has the potential to produce ATP because of the reduced oxidation-reduction coenzyme produced by the process
true
T/F: An important hepatic function of the liver is to catabolize ketone bodies
false
T/F: The beta oxidation of a saturated FA will have a greater ATP producing potential than the beta oxidation of a monounsaturated FA of the same carbon length
true
T/F: The glycerol phosphate shuttle moves glycerol phosphate back and forth across the mitochondrial membrane
false
The initial reaction during gluconeogenesis is the carboxylation of pyruvate which ______ ATP and yields ______ as a product
consumes; OAA
Which of the following sets of metabolites are both potential glucose precursors?
succinyl CoA and alanine
A purely ketogenic AA, i.e. leucine, cannot function as a glucose precursor because _________
catabolism of leucine yields acetyl CoA and acetoacetate
Gluconeogenesis in all cells proceeds to G6P but in the liver the process generates glucose due to the influence of the enzyme _______ found in hepatocytes, but not in most other cells
G-6-phosphatase
Kinetic control of gluconeogenesis occurs using the substrate cycle that employs the enzymes ______, and features the agent fructose 2,6 bisphosphate
PFK-1 and fructose 1,6 bisphosphatase
The conversion of two millimoles of pyruvate into one millimole of glucose consumes _________ millimoles of ATP (Note: for the purposes of this question, GTP is the energetic equivalent of ATP)
6
FA biosynthesis if instigated as _______ is carboxylated to yield _______
acetyl CoA; malonyl CoA
The overall process for the synthesis of the FA 16:0 requires ________ millimoles of the reducing agent NADPH and ______ millimoles of malonylSACP to synthesize one millimole of the fatty acid
14; 7
The pyruvate citrate cycle, that is used to demonstrate the role of carbs in the synthesis of FAs, shows the carboxylation of pyruvate to yield _____ and the decarboxylation of pyruvate to yield _______
OAA; acetyl CoA
One of the important features of the pyruvate-citrate cycle is that _______, which has only been seen in the mitochondrial matrix up to this point, appears in the cellular cytoplasm
acetyl CoA
Which of the following reaction sequences should be followed in order to produce the FA 20:1 DELTA 13 starting with the FA 16:0? (Note: in the answer set, D= desaturation and E= elongation)
D-E-E
The glycerol portion of TAGs and various phosphatides is generated by _______ the glycolytic pathway metabolite ______ to produce L-glycerolphosphate
reducing; pyruvate
The hormone glucagon provides glucose for use in increasing blood sugar concentrations by triggering a series of reactions in ______ that result in increased ______ in those cells
hepatocytes; glycogenolysis and gluconeogenesis
The hormone epinephrine is a _______ hormone and is derived from the cells of the ______
catecholamine; adrenal medulla
Epinephrine enhances _______ as a method of raising blood sugar concentrations
hepatic glycogenolysis
The important intracellular hormonal secondary messenger cAMP is routinely hydrolyzed in hepatocytes under the influence of the enzyme ______ (Note: protein kinase A = cAMP stimulated protein kinase)
phosphodiesterase
Insulin induces quite a number of intracellular processes but one of the most significant is the activation of the glucose transporter _____ that, when activated, allows glucose to enter _______
GLUT-4; adipocytes and SKM cells
Endogenous TAGs are transported from ______ to adipocytes in the form of the lipoprotein called ______
hepatocytes; VLDL
During fasting periods, carbohydrate catabolism is limited in most cells as the enzyme ______ is inhibited by the metabolite _______
pyruvate dehydrogenase; acetyl CoA
The ketone bodies produced by the liver at the expense of FFAs are catabolized in most cells with the exception of ______
hepatocytes and RBCs
One of the functions of folic acid is the action 5, 10 H4 Folate as it supplies a methyl group that is used to convert _____
homocysteine to methionine
One of the starting materials for de-novo synthesis of ATP is ribose-5-p which is routinely available in a cellular context as a component of the pathway called _______
phosphogluconate pathway
Failure to properly regulate the biosynthesis of ATP and GTP can lead to _____
hyperuricemia
Iron is absorbed from the intestinal lumen into the intestinal mucosal cells as the iron reacts with _____ to form the protein ________
apoferritin; ferritin
Hypoglycemia can result as ethyl alcohol is cleared by hepatocytes because hepatic gluconeogenesis is impaired due to the hepatocyte's _______ to provide NAD+ needed to oxidize ethyl alcohol
reduction of pyruvate
This lipoprotein functions to convert cholesterol into cholesterol esters
HDl
A FA can be elongated by reacting it with this metabolite
malonyl CoA
The pancreas releases glucagon in response to this condition
hypoglycemia
This agent is a glucose precursor because it can be oxidized to pyruvate
lactate
One of the functions of tetrahydrofolate is to add a methyl group to UMP to generate this metabolite
TMP
T/F: Most of the AAs that are used in protein structures in the human organism have at least some gluconeogenetic potential
true
T/F: Adenine, guanine, and uric acid all have the structure of a purine nucleus
true
T/F: Acetyl CoA can be produced in the cellular cytoplasm by the pyruvate dehydrogenase mechanism
false
T/F: Hepatic synthesized TAGs are moved to adipocytes for storage in the lipoprotein format called the chylomicron
false
T/F: The hydrolysis of SKM glycogen can provide glucose that can be used to raise blood sugar concentrations
false
FA biosynthesis takes place in the cellular _____ using the agent _______ for reducing power
cytoplasm; NADPH
The biosynthesis of one millimole of the FA 16:0 will consume ________ millimoles of reducing agents
14
When glucose is used as a source of carbon atoms for the FA synthesis, ______ of the six carbons in a given glucose molecule end up being incorporated into the new FA and the other _______ of the six carbons are made into CO2
4;2
Acetyl CoA, for use in FA synthesis, is prepared in the mitochondrion by the decarboxylation of pyruvate and then ______
moved in to the cytoplasm in the form of citrate
If the FA 16:0 is subjected to the following sequence of reactions: elongation, desaturation, elongation; the resultant FA will be ____
20:1 ? (not sure about this answer...)
Which of the following glycolytic components can be used to supply the "glycerol" portion of lipids such as some phosphatides and all TAGs
glyceraldehyde-3-p
Most endogenous cholesterol is synthesized in ______ starting with the metabolite _____
hepatocytes; acetyl CoA
A typical lipoprotein is classified as a(n) ____
mixed micelle
The agent called lipoprotein lipase is found ____
on the plasma membrane of an adipocyte
The TAGs carried to _____ by VLDLs originate in ______
adipocytes; hepatocytes
Water insoluble dietary components such as fat soluble vitamins are carried to the liver as components of ____
chylomicron remnants
The synthesis of cholesterol is regulated by the enzyme ______ that is inhibited by cholesterol and other sterols
HMG CoA reductase
Cholesterol is a biosynthetic precursor for ____
bile acids and steroid hormones
Intracellular cholesterol limits the uptake of cholesterol from the blood plasma by _____
inhibiting the formation of B-100 receptors
The energy content of the TAGs that are stored in adipocytes is moved from the adipocyte to other cells in the form of _______ which are then oxidized at those non-adipocyte locations
FFAs
Oxidation of FAs by SKM cells during starvation produces _______ that inhibits the process called __________ and significantly limits carb catabolism
acetyl CoA; the pyruvate dehydrogenase system
Hepatocytes use the acetyl CoA derived from oxidation to produce ketone bodies, instead of sending the acetyl CoA to the TCA cycle, when ______ is not available
OAA
The phenomenon known as the "tetrahydrofolate trap" occurs when a shortage of the cofactor cobalamin causes the enzyme that catalyzes the reaction used to convert ______ to ______ to fail, and leaves folic acid "trapped" as 5-methyl tetrahydrofolate. (Note: tetrahydrofolate = THF)
homocysteine; methionine
The de novo pathway for the synthesis of purines generates the metabolite ______ which is further processed to prepare _______
inosinic acid; guanine and adenine
Which of the following is the pyrimidine base that requires the B-complex vitamin folic acid, in the form of 5,10 methylene THF, during its synthesis?
thymine
Adrenergic neurons rely on ______ as a source of acetyl CoA for use in the synthesis of acetylcholine
idk...
The absorption of iron from the intestinal lumen depends upon the availability of the agent _______
apoferritin in the intestinal mucosal cells
The cofactor for the enzyme alcohol dehydrogenase, NAD+, is often supplied during periods of hepatic alcohol clearance by the _____
reduction of pyruvate
After a long period of ethyl alcohol clearance by the liver, a person is often _____
acidotic and hypoglycemic
Apolipoprotein B-100 is a component of this type of lipoprotein
LDL
The molecular structure of uric acid can be derived from this agent
ADP
Cholesterol is stored intracellularly in this format
cholesterol esters
Lipolysis is limited by the impact of this hormone
insulin
FA biosynthesis usually starts with this metabolite
acetyl CoA
Since methionine can be synthesized by methylating homocysteine, methionine is not regarded as an essential AA
false
The agent called bile is a multicomponent mixture including water, bile salts, and uncreated cholesterol
true
If the decarboxylation of pyruvate yields acetyl CoA, then the carboxylation of acetyl CoA yields pyruvate
false
Bilirubin is a product of the decay of the "heme" portion of hemoglobin
true
The agent referred to as 'bad cholesterol' in the popular press is actually a cholesterol ester
false
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