This molecule is a product from:
glycolysis
gluconeogenesis
hexose phosphate pathway
anaerobic fermentation
beta-oxidation
The circled carbon position is:
2
3
4
5
1
The molecule can be used to produce glucose in gluconeogenesis is:
A
B
C
D
The molecule which facilitates the transport of fatty acyl-CoA into the mitochondria is:
The molecule produced by acetyl CoA carboxylase for fatty acid synthesis is:
The one whose cell surface localization is enhanced by insulin signaling pathway is?
Glut1
Glut2
Glut3
Glut4
SGLT
Which one is expressed abundantly on neuronal cells?
Which one has a large Km and expressed mainly in hepatocytes and pancreatic alpha/beta-cells?
Which one is abundantly expressed in red blood cells to ensure supply of glucose to erythrocytes?
In which compartment of cell does fatty acid synthesis occur?
soluble cytoplasm (cytosol)
endoplasmic reticulum (ER)
Golgi complex
Mitochondrion (beta oxidation)
nucleus
After entering cells, the immediate product of the first reaction catalyzed by hexokinase is
glucose 6-phosphate
Fructose 1-phosphate
glucose 1-phosphate
Fructose 6-phosphate
glucose 3-phosphate
The major pathway responsible for maintaining blood glucose level 48 hours after a regular meal is:
pentose phosphate pathway, non-oxidative phase
glycogenolysis
glycogenesis
At 50 hours after a regular meal, in addition to glucose, another major carbon fuel supplied by liver to neurons is:
amino acids
fatty acids
fructose
ketone bodies
acetyl CoA
The most important rate limiting enzyme for glycolysis is
pyruvate kinase(also involved)
glyceraldehyde-3 phosphate dehydrogenase
Hexokinases(also invoved)
phosphoglycerate kinase
phosphofructose kinase 1(PFK1)
General effects of glucagon (increase blood glucose level) on skeletal muscle include:
glycolysis increases
glycogen synthesis is stimulated
glycogen synthase activity increases(sysnthsis more glycogren)
glycated myoglobin increases (high levelm of glucose level)
glycogen breakdown increases
When glucagon (need more glucose) binds to cell surface receptors, which of the following response is unlikely?
hepatocytes: glycogen breakdown will be stimulated
adipocytes: fatty acid synthesis will be stimulated
adipocytes: fatty acid release will be stimulated
hepatocytes: gluconeogenesis will be accelerated
skeletal muscle: glycogen breakdown will be stimulated
Under anaerobic condition, one of the products of the glycolysis, pyruvate, is converted to lactate. The biological importance of this reaction is:
To increase lactate levels in cells in order to enhance the expression of lactate dehydrogenase.
Lactate can reduce the intracellular pH, which helps the cell survival
This process is directly coupled with substrate level phosphorylation, hence making ATP
To oxidize NADH to NAD+, a required cofactor for glycolysis; so ATP production via glycolysis can continue
Without oxygen, neurons use lactate as a fuel supply
The pyruvate dehydrogenase complex is mainly located:
on the mitochondrial inner membrane
in the smooth ER
in the peroxisomes
in the mitochondrial matrix
in the cytosol
Ketone bodies can be utilized by the following organs, except for:
brain
liver
heart
skeletal muscle
kidney
Deficiency of fatty acyl-CoA dehydrogenase may lead to:
infant sudden death
infant diabetes
malabsorption of essential fatty acids
stearate diarrhea
vitamin D insufficiency
The following molecules are involved in fatty acid biosynthesis, except for:
Pyruvate carboxylase (coveert to oxdiatate)
malonyl CoA
fatty acid synthase (FAS)
acetyl CoA carboxylase
malic enzyme (in the cytochrome, cutralic get cleaved,use4d NADP as a cofator)
Pyruvate dehydrogenase complexes uses several cofactors which require the following vitamins as precursor, except for:
vitamin B3
vitamin B5(co A)
vitamin B2
vitamin B1
vitamin B6
When some amino acids are utilized as carbon sources, the first step is to remove the amino group by transamination with alpha-KG, which requires a cofactor derived from
vitamin B5
vitamin B7
Vitamin B1
The catabolism of odd-numbered fatty acids requires the following vitamins, except for:
vitamin B12
Which of the following statements regarding oxidation of fatty acids for ATP production is incorrect?
The acyl-CoA needs translocation into mitochondrial matrix
The first step is ATP-dependent activation of fatty acids to form acyl-CoA, using two ATP equivalent per fatty acid molecule.
The translocation step needs carnitine and translocases, also known as CAT, which is rate-limiting
The beta-oxidation enzymes are generally located in the mitochondrial matrix
unsaturated fatty acids cannot be catabolized by beta-oxidation (CAN be)
Glycogen storage disease may be caused by the deficiency of the following enzymes, except for:
glyceraldehyde-P dehydrogenase
glycogen synthase
lysosomal glycosidase
branching enzyme
glycogen phosphorylase
Pancreas (endocrine, extrocine) is important for human metabolism because it produces the following, except for:
glucocorticoids
lipases
glucagon
protease
insulin
The rate limiting step in fatty acid biosynthesis is:
malonyl CoA association with fatty acid synthase (FAS)
acetyl CoA carboxylation by ACC to form malonyl CoA
citrate break down by citrate lyase to form acetyl CoA and OAA in the cytosol
dehydrogenation of malate in the cytosol by malic enzyme
the final step, release of palmitate from FAS
About glycogenin expression and subcellular localization the right combination is:
myocyte: endoplasmic reticulum
cardiac myocyte: peroxisome
hepatocyte: cytosol
adipocyte: mitochondrion
myocyte: mitochondrion(of myocyte and cytosol then this answer could be right)
Which of the following enzymes has the least influence on the speed of glycolytic pathway?
phosphoglycerate mutase
pyruvate kinase
hexose kinase
phosphofructose kinase 1
phosphofructose kinase 2
About AMPK, which one of the following statements is incorrect?
Exercise may activate its activity in myocytes (muscle cells)
It synergizes with insulin, and represses the expression of PEPCK in hepatocyte
It is an intracellular energy sensor regulating the energy metabolism at the cellular level
It is a molecule binds and synergizes with insulin to promote glycolysis in multiple tissues (binds is wrongs)
It is a protein kinase activated by increased level of AMP in cells
The rate of pentose phosphate pathway is limited by G6PD activity, which is allosterically inhibited by:
Decrease of intracellular NADPH levels
Decrease of mitochondrial NADPH levels
Increase of ribose-phosphate levels
Increase of intracellular NADPH levels
Decrease of ribose phosphate levels
Reduced glutathione (GSH) level has been reported to be critical for the recovery of Covid-19 patients. Low intracellular levels of NADPH may cause:
high level of GSH, high level of GSSG
irrelevant to the levels of GSH and GSSG
high level of GSH, low level of GSSG
low level of GSH, high level of GSSG
low level of GSH, low level of GSSG
Which of the following statements about lipid digestion and absorption is NOT correct?
chylomicron carries a protein called Apo protein B100 on its surface
chylomicrons will be transported to the circulation via lymph duct
malabsorption causes lack of essential fatty acids and lipid soluble vitamins
digestion needs lipases secreted by pancreas and bile juice from gallbladder
absorbed lipids will be incorporated into chylomicrons, which is released by intestinal mucosa
During starvation, AMP increase in hepatocytes indicates ATP depletion which stimulates AMPK activity. A well-known activity of AMPK is to phosphorylate acetyl CoA carboxylase.(inhibate fatty acid systhesis) This phosphorylation will:
block glycolysis
decrease fatty acid synthesis
inhibit TCA cycle
stimulate acetyl CoA carboxylase activity
Increase fatty acid synthesis
After an Italian spaghetti meal an increase of blood glucose levels to 12 mM will significantly increase the activity of:
Glut1 and Glut3
Glut1, Glut 2 and Glut3
Fructose 2, 6-bisphosphate is:
An intermediate product of catabolism of fructose to generate ATP
An intermediate metabolite in fatty acid synthesis
An intermediate product of glycolysis which promote the release of O2
A waste byproduct of the glycolytic pathway
A regulatory molecule that allosterically stimulates PFK1 activity and the glycolytic pathway
Completely oxidation of one mole of hexanoyl CoA (an 6C, fully saturated fatty acyl CoA) in mitochondrion maximally may generate:
8 mole ATP
38 mole ATP
42 mole ATP
30 mole ATP
12 mole ATP
Historically, which term was used to indicate the glycolytic processes in normal eukaryotic cells?
The Pasteur Effect
The Embden–Meyerhof–Parnas (EMP Pathway)
The Warburg Effect
The Krebs Effect
The Entner–Doudoroff Pathway (ED Pathway)
For fatty acid biosynthesis, each round contains four reactions. Which of the following accurately describes the four reactions in the correct order?
Condensation-reduction-hydration-reduction
Condensation-dehydrogenation-reduction, reduction
Condensation-reduction-dehydration-reduction
Condensation-reduction-dehydrogenation-reduction
Dehydrogenation, condensation, dehydration, reduction
In pentose phosphate pathway, after two steps of oxidation, the end products from one molecule of G6P will be:
one NADH, one NADPH and one ribose phosphate
two NADH and one pentose phosphate
one NADPH and one pentose phosphate
two NADPH and two pentose phosphate
two NADPH and one pentose phosphate
In a lipogenic liver, the beta oxidation pathway is repressed mainly by:
Increased level of malonyl CoA, which represses CAT activity, thus slowing down the translocation of acyl-CoA to mitochondria
Increased glucagon level, thus promoting the utilization of glucose, repressing utilization of fatty acids
Increase of Ca++ in mitochondrial matrix, which speed up TCA cycle and increased ATP inhibits beta-oxidation
Lack of ATP, fatty acids cannot be activated
Lipogenesis depletes ATP, which activates AMPK and inhibits energy consumption, so cell does not need a fast beta oxidation
Generally, the effects of epinephrine (adrenaline) (make atp in skeletal muscle) on hepatocytes (increase glucose level to sketel mucscle) may include:
inhibiting glycogen breakdown
enhancing glycogen synthase activity
inhibiting glycolysis
stimulating glycogen synthesis
inhibiting glucogenolysis
Which of the following correctly describes the sequence of events of beta-oxidation of fatty acyl CoA in mitochondria?
dehydrogenation-dehydrogenation-hydration-cleavage
dehydrogenation-hydration-dehydrogenation-cleavage
dehydrogenation-hydration-dehydration -cleavage
dehydrogenation-dehydration-dehydrogenation-cleavage
hydration-dehydrogenation-dehydrogenation-cleavage
In gluconeogenesis, how many moles of ATP are required to synthesize one mole glucose from 2 moles of OAA?
12
8
6
The mobilization and utilization of endogenous TAG may not include:
beta-oxidation, resulting in cleavage by thiolase to form acetyl CoA in mitochondrion
ATP-dependent activation of free fatty acid to form acyl-CoA in the cytosol
insulin signaling activates hormone sensitive lipase on white adipose tissue (adipocytes), which releases fatty acids
transport free fatty acids by the circulatory system to cells which need fatty acids as fuel
translocation of acyl-CoA into mitochondria, a carnitine-dependent process
Which of the following carbon sources cannot be used in gluconeogenesis?
OAA from aspartate catabolism
riboses from pentose pathway
acetyl CoA from beta oxidation
glycerol-3 phosphate released from breakdown of phospholipids
alpha-ketoglutarate from glutamate and glutamine catabolism
About insulin, which of the following statement is NOT correct?
its target organs/tissues include liver, muscle and adipose
its release is triggered by increased ATP levels in β cells
it promotes glycogen phosphorolysis and glycolysis to generate large amount of ATP in muscle (not promote glycogen phosphorolysis)
it may regulate the expression of metabolic enzymes.
it is produced by pancreatic β cells
Insulin stimulates PI3K-PKB pathway, which may lead to:
converting phosphorylated glucose to glucose
converting glycogen phosphorylase a to phosphorylase b
converting glycogen synthase a to glycogen synthase b
increasing internalized Glut4
converting glycogen phosphorylase b to phosphorylase a
Some steps in the glycolytic pathway cannot be simply reversed in gluconeogenesis, thus need bypassing by different enzymes; these steps include the following, except for:
hexokinase-catalyzed formation of G6P
pyruvate kinase-catalyzed formation of pyruvate
PFK1-catalyzed formation of F1,6BP
Phosphoenolpyruvate to pyruvate, accompanied by substrate level phosphorylation
F1,6BP broken by aldolase
About ketone bodies, which of the following statement is not correct?
are produced by hepatocytes
can be used by all tissues, such as neurons and hepatocytes
is an alternative fuel, particularly important for brain
are produced from acetyl CoA
overproduction of ketone bodies may occur in diabetic patients, even with hyperglycemia
Which process is NOT considered a general function of the pentose phosphate pathway?
The production of pentose phosphate for biosynthesis of some cofactors
the production of NADPH to help prevent oxidative stress in erythrocytes
The transfer of electrons to the electron transport chain for ATP production
the production of pentoses necessary for nucleotide synthesis
the production of NADPH for reductive biosynthesis in adipose cells
In humans, the Cori cycle is an example of metabolic coordination among active skeletal muscle, the circulatory system and liver. Which two metabolic pathways are involved in this cycle?
gluconeogenesis in muscle and glycogenolysis in liver
glycolysis in muscle and gluconeogenesis in liver
glycolysis in muscle and the pentose phosphate pathway in liver
pentose phosphate pathway in muscle and gluconeogenesis in liver
beta-oxidation in muscle and ketogenesis in liver
In some cell types, insulin signaling will triggers the glucose transporter 4 translocating to the cell membrane, hence increasing the transport of glucose into cells. Which cell types respond to insulin in this manner?
hepatocytes and skeletal myocytes
erythrocytes and neurons
erythrocytes and adipocytes
skeletal myocytes and adipocytes
neurons and the hepatocytes
Under anaerobic conditions, yeast performs two additional steps after glycolysis; which convert pyruvate to ethanol. What is the purpose served by these two additional steps in the metabolism of yeast cells?
They know our students like beer.
They are required to complete the oxidation of glucose and maximizing ATP production
They are required to re-oxidize limited amounts of NADH to NAD+ and decrease pyruvate level, thus sustaining continuous glycolysis to ensure ATP production
They are required to remove pyruvate, ensuring ATP production.
They are required to oxidize NADH to generate ATP
Which of the following carbon sources cannot be used in gluconeogenesis in human cells?
succinyl-CoA
aspartate
palmitate
glutamate
alanine
Which statement is accurate, regarding fatty acids stored in adipocytes?
They are part of the cell components, and cannot be oxidized for energy in this tissue.
They are primarily bound to albumin and stored in lipid droplets.
There is a constant movement of fatty acids in and out of adipose tissues, which is independent of hormone signals.
Upon glucagon signaling, fatty acids are converted into ketone bodies in adipocytes
In adipocytes, fatty acids up-taken from the bloodstream are assembled into triglycerides by directly esterifying to glycerol.
Which statement is INCORRECT regarding the transport of long-chained fatty acids into the mitochondrial matrix?
The cytosolic and mitochondrial matrix pools of coenzyme A are separated by biomembranes
It is not a rate-limiting step in the oxidation of these fatty acids.
Once these fatty acyl molecules are in the matrix, carnitine can be transported out of mitochondria.
It is inhibited by the increase of malonyl-CoA levels
Patients with a carnitine deficiency are likely to have impaired betaoxidation of fatty acids
For catabolism of the amino acids with hydroxyl groups, the amino groups are usually removed by:
decarboxylation initiated deaminination
hydrolysis to remove α-amino group
transamination to remove α-amino group
dehydration initiated deamination
oxidative deamination
Pentose phosphate pathway has two phases: the oxidative phase and the non-oxidative phase.
True
False
PLP is a cofactor required for glycogen phosphorylase activity, which is derived from vitamin B6.
Human fatty acid synthase is an enzyme complex of 7 subunits, each with a specialized activity. ( for human we have 1 only)
beta-oxidation of fatty acids also occurs in peroxisomes, which similarly has ETC to make ATP. N(peroxisome do not have ETC)
The oxidized glutathione protects enzymes from oxidative damage. (used reduced)
G6P phosphatase is an enzyme specifically expressed in hepatocytes.
32 mole ATP
48 mole ATP
Each round of beta-oxidation has 4 steps. The correct order of the four steps are:
dehydrogenation to generate FADH2, Reduction, dehydrogenation to generate NADH, cleavage to for to acetyl CoA and a new acyl CoA.
dehydrogenation to generate FADH2, Hydration, dehydrogenation to generate NADH, cleavage to for to acetyl CoA and a new acyl CoA.
dehydrogenation to generate NADH, Hydration, dehydrogenation to generate FADH2, cleavage to for to acetyl CoA and a new acyl CoA.
dehydrogenation to generate FADH2, dehydration, dehydrogenation to generate NADH, cleavage to for to acetyl CoA and a new acyl CoA.
For beta oxidation of fatty acids as energy, the rate limiting step is:
transportation into mitochondria
biosynthesis of fatty acyl CoA in the mitochondria
Activation by ATP
biosynthesis of fatty acyl-CoA in the cytosol
Fatty acyl CoA dehydrogenation
Regarding propionyl-CoA metabolism, which of the following statement is incorrect?
Propionyl-CoA is a rare metabolite, which cannot be further catabolized by human cells, thus being disposed by urine
further converting methylmalonyl-Coa to succinyl-CoA depends on vitamin B12
Propionyl-CoA may arise from diet, or catabolism of fatty acids and some amino acids.
Propionyl-CoA (3C) can be converted to Methylmainyl-CoA (4C) after a carboxylation reaction facilitated by vitamin B7
The structure of vitamin B12 is very complicate and contains cobalt.
In glycolysis pathway, the energy released during the breakdown of glucose to pyruvate is harvested or stored by:
ATP and NADH
NADH
FADH2
phosphoenolpyruvate
Biochemical features of glycolysis include the following, except for:
High fuel efficiency
oxygen-independent
electron-transport chain independent
mitochondrion-independent
Rapid production of ATP
About the overall steps of digestion and absorbtion of dietary fatty acids, which of the following is correct?
After absorption to mucosa cells, free fatty acids are used to re-synthesize TAG, which is then packed into chylomicron.
chylomicron is transported to liver via portal vein, an via hepatic vein to reach circulation
Fat digested to free fatty acids, which are absorbed into mucosa cells and released into blood circulation directly.
chylomicron is purely compose of lipids, without protein components.
In amino acid catabolism, amino-transferases remove the alpha-amino groups in transamination reactions. This type of enzymes requires an important cofactor derived from:
B3
B2
B5
B6
B12
Pyruvate dehydrogenase complex contains 3 enzymatic activities, sequentially named E1,E2 and E3.
Which of the following description of the E1-E3 is correct?
E1: pyruvate dehydrogenase; E1: pyruvate transacetylase; E3: dihydrolipoyl dehydrogenase
E1: pyruvate decarboxylase; E2: dihydrolipoyl transacetylase; E3: dihydrolipoyl dehydrogenase
E1: pyruvate dehydrogenase; E2: dihydrolipoyl transacetylase; E3: dihydrolipoyl dehydrogenase
E1: pyruvate dehydrogenase; E2: dihydrolipoyl dehydrogenase; E3: dihydrolipoyl transacetylase
E1: dihydrolipoyl dehydrogenase; E2: dihydrolipoyl transacetylase; E3: pyruvate dehydrogenase
The Entner-Doudoroff Pathway (ED Pathway)
After uptaking into cardiomyocyte, a 18C-fatty acid will be likely utilized in the following order:
Synthesized into fatty acyl CoA, transported into, Activation by ATP, beta-oxidation to generate Acetyl coA
Activation by ATP in cytosol, converting to Fatty acyl CoA, transported into mitochondrion, beta-oxidation to generate Acetyl coA
Activation by ATP in cytosol, converting to Fatty acyl CoA, beta-oxidation to generate Acetyl coA, transporting acetyl coA into mitochondrion
Activation by ATP in cytosol, transported into mitochondrion, converting to Fatty acyl CoA, beta-oxidation to generate Acetyl coA
Transported into mitochondrion, activation by ATP, converting to fatty acyl CoA, beta-oxidation to generate Acetyl coA
transamination to remove a-amino group
hydrolysis to remove a-amino group
B1
B7
About anaerobic glycolysis, which of the following statement is incorrect?
In human cells, anaerobic glycolysis generates alcohol, which later on degraded by alcohol dehydrogenase to acetaldehyde upon reoxygenation.
Anaerobic glycolysis in human cells generates lactate, not alcohol
Anaerobic glycolysis to produce ATP is developed earlier than oxidative phosphorylation method evolutionarily.
in some bacteria, anaerobic glycolysis generates lactate to recover NAD+ (oxidized)
In yeast, anaerobic glycolysis generates alcohol to regenerated NAD+ (oxidized)
The most important regulatory enzyme of glycolytic pathway is:
phosphofructokinase-1 (PFK1), which converts F6P to F1,6BP.
phosphoglycerate kinase, which catalyzes the first production of ATP
Glyceraldehyde-3-phospate dehydrogenase, which catalyzes the generation of NADH
Aldolase A, which breaks the 6C hexose-phosphate to 3C triose phosphate
pyruvate kinase, which chatalyzes the 2nd production of ATP
In gluconeogenesis, the rate limiting enzymes are:
PEP carboxykinase
pyruvate carboxylase
F1,6 bisphosphatase
Fatty acid biosynthesis requires high concentrations of NADPH. Which compartment of human cell does fatty acid synthesis occur?
mitochondrion
The rate limiting step of fatty acid synthesis is:
condensation of malony-CoA with growing fatty acyl chain
beta oxidation to generate acetyl CoA as substrates
transfer citrate out of mitochondria
recognizing and binding malonyl CoA by Acyl carrier protein (ACP)
carboxylation of acetyl CoA to form malonyl CoA
glycerol 3-P dehydrogenase
Deficiency of a fatty acyl-CoA dehydrogenase may lead to:
myocyte: mitochondrion
hepatocyte: mitochondrion
Completely oxidizing a G6P to 6CO2 via the pentose pathway may result in:
4 NADPH
8 NADPH
6 NADPH
12 NADPH
2 NADPH
For fatty acid biosynthesis, each round contains four reactions. Which of the following correctly describes the four reactions in the correct sequence?
The major products of pentose pathway with important biological roles is/are:
NADPH
pentose phosphate
erythrose 4-phosphate
NADPH and pentose phosphate
NADPH, pentose phophate and erythrose 4-phosphate
1. The single most important enzyme involved in glycogen synthesis is:
phosphoglucomutase
Glycogen synthetase
Glycogen synthase
UDP-Sugar Pyrophosphorylase
glycogen branching enzyme
Hepatocytes synthesize fatty acids, and most of the fatty acids are esterified into TAG, which will be:
released to circulation directly and carried by plasma proteins
carried by a lipoprotein called VLDL through the circulation
carried by a lipoprotein called LDL through the circulation
carried by either VLDL or chylomicron through the circulation
carried by a lipoprotien called chylomicron through the circulation
In most cells, reduced glutathione is used to protect cells from damage caused by reactive oxygen species. The most important metabolic pathway that maintains the intracellular levels of reduced glutathione is:
pentose pathway
glycolytic pathway
krebs cycle
fatty acid beta oxidation
After biosynthesis, palmitate can be elongated to stearate in either mitochondria or endoplasmic reticulum. Both palmitate or stearate can be modified by desaturation at delta9, which is catalyzed by an enzyme located at:
mitochondria
rough endoplasmic reticulum
cytosol
smooth endoplasmic reticulum
cell surface
Glycolysis contains 10 steps, among which 7 steps are reversible and 3 steps are not reversible in glyconeogenesis. The three non-reversible steps are:
A. hexokinase catalyzed Glucose to G6P
B. phosphofructokinase (PFK) catalyzed F6P to F1, 6BP
C. Pyruvate kinase catalyzed PEP to enol pyruvate
A, B, and C
A and B
The most important substrate/s for gluconeogenesis upon starvation is/are:
carbon skeletons from catabolism of most amino acids
fatty acids from TAG break down
propionyl-CoA from catabolism of odd-numbered fatty acids
glycerol from TAG breakdown
acetyl CoA from fatty acid beta-oxidation
Por favor espera - en proceso…