Questão 1
Questão
what is the fate of lipid digestion products absorbed by intestinal mucosal cells?
Responda
-
export of short chain fatty acids to the portal blood
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re-esteriification of long chain fatty acids forming triacylglycerols
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formation of lipoprotein particles: chylomicron
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all the above
Questão 2
Questão
after an overnight fast which of the following enzymes (proteins) show low activity?
Questão 3
Questão
which one of the following statements about prostaglandin synthesis is INCORRECT
Responda
-
Phospholipase A2 or phospholipase C release prostaglandin precursors from plasma membrane phospholipids
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arachidonic acid is a major precursor of prostaglandins
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Prostaglandins are derived from an essential fatty acid
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prostaglandins are produced through the action of lipoxygenase
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prostaglandins synthesis is inhibited by glucocorticoids and aspirin
Questão 4
Questão
uncoupling of oxidative phosphorylation could occur with
Responda
-
A high concentration of glucocorticoids
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A high concentration of thyroxine
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A high concentration of adrenaline
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A high concentration of insulin
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A high concentration of glucagon
Questão 5
Questão
sodium-glucose transporter in the intestine
Questão 6
Questão
GLUT 2 in liver cells and pancreatic β cells
Responda
-
has low Km (high affinity to glucose)
-
is suitable for glucose uptake during fasting
-
acts as glucose sensor , along with glucokinase , in β-cells of pancreas
-
all the above
Questão 7
Questão
according to Pasteur effect
Responda
-
glycolysis proceeds in a faster rate in presence of oxygen
-
oxygen decreases the rate of glycolysis
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glycolysis produces more ATP from a glucose molecule in absence of oxygen
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oxygen decreases the production of ATP from one glucose molecule
Questão 8
Questão
the bi-functional enzyme PFK2/fructose2,6-bisphosphatase
Responda
-
controls the level of fructose 2,6-bisphosphate ,hence the activity of PFK1
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is phosphorylated by cAMP-dependant protein kinase under the effect of glucagon and epinephrine
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is dephosphorylated by protein phosphatase under the effect of insulin
-
all the above
Questão 9
Questão
which of the following is true about fatty acid oxidation
Responda
-
the active form of fatty acid is fatty acyl coA
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fatty acid is activated by acyl coA synthetase of the inner mitochondrial membrane
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with fatty acid activation ATP is hydrolyzed to ADP + inorganic phosphate
-
Fatty acyl coA is used only for energy production
Questão 10
Questão
deficiency of carnitine acyl transferase may NOT lead to
Responda
-
failure of fatty acid oxidation
-
hypoglycemia
-
ketoacidosis
-
hepatomegaly , seizures and cardiomyopathy leading to infantile death
Questão 11
Questão
mitochondrial β-oxidation pathway produces propionyl CoA from
Questão 12
Questão
Zellweger's (cerebro-hepato-renal) syndrome is characterizd by accumulation
Questão 13
Questão
ِAn enzyme is not involved in glycolysis in muscle is
Questão 14
Questão
the best description of the difference between glucokinase and hexokinase is
Responda
-
hexokinase is found in liver and kidney , while hexokinase is present in nearly all tissues
-
hexokinase has much higher Km for glucose
-
glucokinase is found only in tissues that are totally dependent on glucose for fuel , such as brain & RBCs
-
glucokinase & hexokinase are zymogens
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glucokinase but not hexokinase is induced by insulin
Questão 15
Questão
An abnormal accumulation of galactose 1-p in liver is usually caused by a deficiency
Questão 16
Questão
the oxidative decarboxylation of all α-keto acids is similar to that of pyruvate. A common requirment for all is
Responda
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NADP
-
Acetyl CoA
-
Lipoic acid
-
α -ketoglutarate
-
GDP
Questão 17
Questão
mitochondria in brown fat of human infants increase heat generation .this result from an increased rate of electron transport due to
Responda
-
inhibition of ADP-ATP antiporter
-
inhibition of F1-Fo ATP synthase
-
blockage of NADH reoxidation
-
increased permeability of the inner mitochondrial membrane
-
decreased rate of oxygen consumption
Questão 18
Questão
all the electron carrying groups of the respiratory chain
Responda
-
are fixed to the inner mitochondrial membrane
-
are arranged in an order of descending redox potential
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contain iron as an electron acceptor
-
participate in the building up of the proton gradient
-
none of the above
Questão 19
Questão
the following enzyme is a constituent of pentose phosphate pathway
Questão 20
Questão
a substance that is not an intermediate in formation of glucuronic acid from glucose
Responda
-
UDP-galactose
-
UDP-glucose
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Glucose 6-phosphate
-
UDP-glucuronic acid
-
glucose 1-phosphate
Questão 21
Questão
in the break down of muscle glycogen the predominant product is
Responda
-
glucose
-
glucose 1-phosphate
-
UDP-glucose
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maltose
-
maltriose
Questão 22
Questão
the regulation of glycogenolysis in muscle differ from that in the liver
Responda
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muscles lack receptors of glucagon
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only the liver uses β-adrenergic receptors for this regulation
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only muscles respond to epinephrine
-
muscle glycogenolysis does not respond to stimulation by intracellular calcium
-
muscle produces mostly glucose from glycogen
Questão 23
Questão
mammalian fatty acids desaturase systems introduce double bonds
Responda
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at Δ4, Δ5, Δ6, Δ9 positions
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at ω3, ω6 and ω9 positions
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between an existing double bond and methyl carbon
-
all the above
Questão 24
Questão
lypolysis in adipose tissue is initiated by
Questão 25
Questão
The enzyme required for both the synthesis of acetoacetate and its utilization as a fuel is
Questão 26
Questão
Receptor-mediated uptake of excess LDL results in all the following Except
Responda
-
increased estrification of cholesterol
-
increased production of mevalonate
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decreased synthesis of HMG-CoA reductase
-
decreased synthesis of the LDL recepttor
-
decreased receptor-mediated endocytosis of LDL
Questão 27
Questão
In man serum lipoprotein fraction with the highest cholesterol content is
Responda
-
α-lipoprotein
-
β-lipoprotein
-
pre β-lipoprotein
-
chylomicrons
-
pre-albumin
Questão 28
Questão
secondary bile acids are distinguishable from the primary bile acids because they lack
Responda
-
glycine
-
taurine
-
a hydroxyl group
-
a methyl group
-
a carboxylate group
Questão 29
Questão
what is the enzyme used for cholesterol storage
Questão 30
Questão
cori cycle transfers
Responda
-
alanine from muscle to liver
-
lactic from liver to muscle
-
lactic from exercising muscle or RBCs to liver
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Glucose from muscle to liver