1857938
Descripción
Test por #أطباء_2020 , actualizado hace más de 1 año
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Creado por #أطباء_2020
hace casi 10 años
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Pregunta 1
Pregunta
what is the fate of lipid digestion products absorbed by intestinal mucosal cells?
Respuesta
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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
Pregunta 2
Pregunta
after an overnight fast which of the following enzymes (proteins) show low activity?
Respuesta
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glucokinase in liver
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hexokinase in brain
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GluT1 transporter
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glucose 6 phosphatase in liver
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α-ketoglutaric dehydrogenase in brain
Pregunta 3
Pregunta
which one of the following statements about prostaglandin synthesis is INCORRECT
Respuesta
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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
Pregunta 4
Pregunta
uncoupling of oxidative phosphorylation could occur with
Respuesta
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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
Pregunta 5
Pregunta
sodium-glucose transporter in the intestine
Respuesta
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act as symport
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is located at the serosal side of the intestinal cell membrane
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binds ATP
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transport both sodium and glucose concentration gradient
Pregunta 6
Pregunta
GLUT 2 in liver cells and pancreatic β cells
Respuesta
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has low Km (high affinity to glucose)
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is suitable for glucose uptake during fasting
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acts as glucose sensor , along with glucokinase , in β-cells of pancreas
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all the above
Pregunta 7
Pregunta
according to Pasteur effect
Respuesta
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glycolysis proceeds in a faster rate in presence of oxygen
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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
Pregunta 8
Pregunta
the bi-functional enzyme PFK2/fructose2,6-bisphosphatase
Respuesta
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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
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all the above
Pregunta 9
Pregunta
which of the following is true about fatty acid oxidation
Respuesta
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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
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Fatty acyl coA is used only for energy production
Pregunta 10
Pregunta
deficiency of carnitine acyl transferase may NOT lead to
Respuesta
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failure of fatty acid oxidation
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hypoglycemia
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ketoacidosis
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hepatomegaly , seizures and cardiomyopathy leading to infantile death
Pregunta 11
Pregunta
mitochondrial β-oxidation pathway produces propionyl CoA from
Respuesta
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fatty acid with odd number of carbons
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phytanic acid derived from chlorophyll
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both (A) & (b)
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neither (A) nor (B)
Pregunta 12
Pregunta
Zellweger's (cerebro-hepato-renal) syndrome is characterizd by accumulation
Respuesta
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phytanic acid
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very long chain polyenoic acid
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both (A) & (B)
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neither (A) nor (B)
Pregunta 13
Pregunta
ِAn enzyme is not involved in glycolysis in muscle is
Respuesta
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aldolase
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glyceraldehyde 3-phosphate dehydrogenase
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enolase
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pyruvate kinase
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bisphosphoglycerate mutase
Pregunta 14
Pregunta
the best description of the difference between glucokinase and hexokinase is
Respuesta
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hexokinase is found in liver and kidney , while hexokinase is present in nearly all tissues
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hexokinase has much higher Km for glucose
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glucokinase is found only in tissues that are totally dependent on glucose for fuel , such as brain & RBCs
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glucokinase & hexokinase are zymogens
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glucokinase but not hexokinase is induced by insulin
Pregunta 15
Pregunta
An abnormal accumulation of galactose 1-p in liver is usually caused by a deficiency
Respuesta
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glucose 6-phosphate dehydrogenase
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glucose 6-phosphatse
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galactokinase
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galactose 1-phosphate uridylyl transferase
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hexokinase
Pregunta 16
Pregunta
the oxidative decarboxylation of all α-keto acids is similar to that of pyruvate. A common requirment for all is
Respuesta
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NADP
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Acetyl CoA
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Lipoic acid
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α -ketoglutarate
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GDP
Pregunta 17
Pregunta
mitochondria in brown fat of human infants increase heat generation .this result from an increased rate of electron transport due to
Respuesta
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inhibition of ADP-ATP antiporter
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inhibition of F1-Fo ATP synthase
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blockage of NADH reoxidation
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increased permeability of the inner mitochondrial membrane
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decreased rate of oxygen consumption
Pregunta 18
Pregunta
all the electron carrying groups of the respiratory chain
Respuesta
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are fixed to the inner mitochondrial membrane
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are arranged in an order of descending redox potential
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contain iron as an electron acceptor
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participate in the building up of the proton gradient
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none of the above
Pregunta 19
Pregunta
the following enzyme is a constituent of pentose phosphate pathway
Respuesta
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glucose 6-phosphatase
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phosphorylase
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hexokinase
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glucose 6-phosphate dehydrogenase
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phosphohexoisomerase
Pregunta 20
Pregunta
a substance that is not an intermediate in formation of glucuronic acid from glucose
Respuesta
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UDP-galactose
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UDP-glucose
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Glucose 6-phosphate
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UDP-glucuronic acid
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glucose 1-phosphate
Pregunta 21
Pregunta
in the break down of muscle glycogen the predominant product is
Respuesta
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glucose
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glucose 1-phosphate
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UDP-glucose
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maltose
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maltriose
Pregunta 22
Pregunta
the regulation of glycogenolysis in muscle differ from that in the liver
Respuesta
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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
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muscle glycogenolysis does not respond to stimulation by intracellular calcium
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muscle produces mostly glucose from glycogen
Pregunta 23
Pregunta
mammalian fatty acids desaturase systems introduce double bonds
Respuesta
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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
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all the above
Pregunta 24
Pregunta
lypolysis in adipose tissue is initiated by
Respuesta
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Food intake
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ketoacidosis
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fasting
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high insulin/glucagon ratio
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high fatty acid concentration
Pregunta 25
Pregunta
The enzyme required for both the synthesis of acetoacetate and its utilization as a fuel is
Respuesta
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succinyl coA : acetoacetate CoA transferase
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HMG-CoA synthase
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thiolase
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HMG-CoA lyase
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β-hydroxybutyrate dehydrogenase
Pregunta 26
Pregunta
Receptor-mediated uptake of excess LDL results in all the following Except
Respuesta
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increased estrification of cholesterol
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increased production of mevalonate
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decreased synthesis of HMG-CoA reductase
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decreased synthesis of the LDL recepttor
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decreased receptor-mediated endocytosis of LDL
Pregunta 27
Pregunta
In man serum lipoprotein fraction with the highest cholesterol content is
Respuesta
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α-lipoprotein
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β-lipoprotein
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pre β-lipoprotein
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chylomicrons
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pre-albumin
Pregunta 28
Pregunta
secondary bile acids are distinguishable from the primary bile acids because they lack
Respuesta
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glycine
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taurine
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a hydroxyl group
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a methyl group
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a carboxylate group
Pregunta 29
Pregunta
what is the enzyme used for cholesterol storage
Respuesta
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HMG-CoA reductase
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Lecithin cholesterol acyl transferase
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lipoprotein lipase
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Acyl CoA cholesterol acyl transferase
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cholesterol esterase
Pregunta 30
Pregunta
cori cycle transfers
Respuesta
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alanine from muscle to liver
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lactic from liver to muscle
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lactic from exercising muscle or RBCs to liver
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Glucose from muscle to liver
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