1857938
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Quiz von #أطباء_2020 , aktualisiert more than 1 year ago
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Erstellt von #أطباء_2020
vor fast 10 Jahre
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Frage 1
Frage
what is the fate of lipid digestion products absorbed by intestinal mucosal cells?
Antworten
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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
-
formation of lipoprotein particles: chylomicron
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all the above
Frage 2
Frage
after an overnight fast which of the following enzymes (proteins) show low activity?
Antworten
-
glucokinase in liver
-
hexokinase in brain
-
GluT1 transporter
-
glucose 6 phosphatase in liver
-
α-ketoglutaric dehydrogenase in brain
Frage 3
Frage
which one of the following statements about prostaglandin synthesis is INCORRECT
Antworten
-
Phospholipase A2 or phospholipase C release prostaglandin precursors from plasma membrane phospholipids
-
arachidonic acid is a major precursor of prostaglandins
-
Prostaglandins are derived from an essential fatty acid
-
prostaglandins are produced through the action of lipoxygenase
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prostaglandins synthesis is inhibited by glucocorticoids and aspirin
Frage 4
Frage
uncoupling of oxidative phosphorylation could occur with
Antworten
-
A high concentration of glucocorticoids
-
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
Frage 5
Frage
sodium-glucose transporter in the intestine
Antworten
-
act as symport
-
is located at the serosal side of the intestinal cell membrane
-
binds ATP
-
transport both sodium and glucose concentration gradient
Frage 6
Frage
GLUT 2 in liver cells and pancreatic β cells
Antworten
-
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
Frage 7
Frage
according to Pasteur effect
Antworten
-
glycolysis proceeds in a faster rate in presence of oxygen
-
oxygen decreases the rate of glycolysis
-
glycolysis produces more ATP from a glucose molecule in absence of oxygen
-
oxygen decreases the production of ATP from one glucose molecule
Frage 8
Frage
the bi-functional enzyme PFK2/fructose2,6-bisphosphatase
Antworten
-
controls the level of fructose 2,6-bisphosphate ,hence the activity of PFK1
-
is phosphorylated by cAMP-dependant protein kinase under the effect of glucagon and epinephrine
-
is dephosphorylated by protein phosphatase under the effect of insulin
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all the above
Frage 9
Frage
which of the following is true about fatty acid oxidation
Antworten
-
the active form of fatty acid is fatty acyl coA
-
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
Frage 10
Frage
deficiency of carnitine acyl transferase may NOT lead to
Antworten
-
failure of fatty acid oxidation
-
hypoglycemia
-
ketoacidosis
-
hepatomegaly , seizures and cardiomyopathy leading to infantile death
Frage 11
Frage
mitochondrial β-oxidation pathway produces propionyl CoA from
Antworten
-
fatty acid with odd number of carbons
-
phytanic acid derived from chlorophyll
-
both (A) & (b)
-
neither (A) nor (B)
Frage 12
Frage
Zellweger's (cerebro-hepato-renal) syndrome is characterizd by accumulation
Antworten
-
phytanic acid
-
very long chain polyenoic acid
-
both (A) & (B)
-
neither (A) nor (B)
Frage 13
Frage
ِAn enzyme is not involved in glycolysis in muscle is
Antworten
-
aldolase
-
glyceraldehyde 3-phosphate dehydrogenase
-
enolase
-
pyruvate kinase
-
bisphosphoglycerate mutase
Frage 14
Frage
the best description of the difference between glucokinase and hexokinase is
Antworten
-
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
-
glucokinase but not hexokinase is induced by insulin
Frage 15
Frage
An abnormal accumulation of galactose 1-p in liver is usually caused by a deficiency
Antworten
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glucose 6-phosphate dehydrogenase
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glucose 6-phosphatse
-
galactokinase
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galactose 1-phosphate uridylyl transferase
-
hexokinase
Frage 16
Frage
the oxidative decarboxylation of all α-keto acids is similar to that of pyruvate. A common requirment for all is
Antworten
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NADP
-
Acetyl CoA
-
Lipoic acid
-
α -ketoglutarate
-
GDP
Frage 17
Frage
mitochondria in brown fat of human infants increase heat generation .this result from an increased rate of electron transport due to
Antworten
-
inhibition of ADP-ATP antiporter
-
inhibition of F1-Fo ATP synthase
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blockage of NADH reoxidation
-
increased permeability of the inner mitochondrial membrane
-
decreased rate of oxygen consumption
Frage 18
Frage
all the electron carrying groups of the respiratory chain
Antworten
-
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
-
participate in the building up of the proton gradient
-
none of the above
Frage 19
Frage
the following enzyme is a constituent of pentose phosphate pathway
Antworten
-
glucose 6-phosphatase
-
phosphorylase
-
hexokinase
-
glucose 6-phosphate dehydrogenase
-
phosphohexoisomerase
Frage 20
Frage
a substance that is not an intermediate in formation of glucuronic acid from glucose
Antworten
-
UDP-galactose
-
UDP-glucose
-
Glucose 6-phosphate
-
UDP-glucuronic acid
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glucose 1-phosphate
Frage 21
Frage
in the break down of muscle glycogen the predominant product is
Antworten
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glucose
-
glucose 1-phosphate
-
UDP-glucose
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maltose
-
maltriose
Frage 22
Frage
the regulation of glycogenolysis in muscle differ from that in the liver
Antworten
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muscles lack receptors of glucagon
-
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
Frage 23
Frage
mammalian fatty acids desaturase systems introduce double bonds
Antworten
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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
Frage 24
Frage
lypolysis in adipose tissue is initiated by
Antworten
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Food intake
-
ketoacidosis
-
fasting
-
high insulin/glucagon ratio
-
high fatty acid concentration
Frage 25
Frage
The enzyme required for both the synthesis of acetoacetate and its utilization as a fuel is
Antworten
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succinyl coA : acetoacetate CoA transferase
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HMG-CoA synthase
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thiolase
-
HMG-CoA lyase
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β-hydroxybutyrate dehydrogenase
Frage 26
Frage
Receptor-mediated uptake of excess LDL results in all the following Except
Antworten
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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
-
decreased synthesis of the LDL recepttor
-
decreased receptor-mediated endocytosis of LDL
Frage 27
Frage
In man serum lipoprotein fraction with the highest cholesterol content is
Antworten
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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
Frage 28
Frage
secondary bile acids are distinguishable from the primary bile acids because they lack
Antworten
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glycine
-
taurine
-
a hydroxyl group
-
a methyl group
-
a carboxylate group
Frage 29
Frage
what is the enzyme used for cholesterol storage
Antworten
-
HMG-CoA reductase
-
Lecithin cholesterol acyl transferase
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lipoprotein lipase
-
Acyl CoA cholesterol acyl transferase
-
cholesterol esterase
Frage 30
Frage
cori cycle transfers
Antworten
-
alanine from muscle to liver
-
lactic from liver to muscle
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lactic from exercising muscle or RBCs to liver
-
Glucose from muscle to liver
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