65 - which enzyme is the major control point for glycolysis in muscle under most conditions .
a- glucokinase
b- hexokinase
c- phosphofructokinase
d- pyruvate kinase
answer is c .
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66 - ATP in fast twitch muscle fibres is supplied predominantly by which type of glycolysis
a- aerobic
b- anaerobic
answer is b . anaerobic glycolysis .
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67 - the rate of ATP production by anaerobic glycolysis can be upto 100 times faster than that of oxidative phosphorylation .
the above statement is true .
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68 - under which conditions is the complete oxidation of pyruvate mediated by citric acid cycle ?
a- aerobic
b- anaerobic
answer is a .
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69 - impaired substrate cycling may lead to a lack of nonshivering thermogenesis and result in cold sensitivity in obese individuals .
the above statement is true .
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70 - which molecule acts as a signal amplifier when concentrations of ATP are low to increase the phosphofructokinase activity ?
a- ADP
b- ATP
c- AMP
d- NADH
answer is c . AMP .
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71 - Ribulose 5 phosphate ( RU5P ) is converted to ribose 5 phosphate ( R5P ) by the enzyme ?
a- ribulose 5 phosphate dehydrogenase
b- ribose 5 phosphate dehydrogenase
c- RU5P ISOMERASE
d- R5P ISOMERASE
the answer is C .
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72 - which aminoacid side chain forms the schiff base with the substrate in the aldolase reaction ?
a- arginine
b- serine
c- tyrosine
d- lysine
answer is d.
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73 - lactate formed in skeletal muscle cells during anaerobic glycolysis is carried back to the liver , where it is used to synthesize
a- glucose
b- fructose
c- fatty acids
d- amino acids
answer is a .
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74 - flouride ion inhibits glycolysis by inhibiting the action of which enzyme ?
answer - enolase
aldolase
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75 - what is the enzyme which catalyses the formation of glyceraldehyde 3 phosphate and dihydroxy acetone phosphate ?
a- aldolase
b- enolase
c- kinase
d- mutase
answer is a . aldolase .
TO READ COMPLETELY ABOUT GLYCOLYSIS CLICK HERE
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Showing posts with label NADH. Show all posts
Showing posts with label NADH. Show all posts
Tuesday, January 8, 2008
3 - biochemistry mcqs - 11 to 20 - citric acid cycle
11 - citrate has the ability to inhibit this enzyme by competing with oxaloacetate ?
answer is CITRATE SYNTHASE .
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12 - The molecule which inhibits isocitrate dehydrogenase ?
answer is CALCIUM . Ca +2.
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13 - this molecule regulates the citric acid cycle at many points , including the activation of pyruvate dehydrogenase phosphatase , isocitrate dehydrogenase and alpha ketoglutarate dehydrogenase .
answer is SERINE .
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14 - In e coli , this enzyme is inactivated by the phosphorylation of a serine residue in the active site ?
answer is isocitrate dehydrogenase .
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15 - covalent modification of E 1 occurs by the specific phosphorylation of WHICH residue in a reaction catalysed by pyruvate dehydrogenase kinase ?
answer is ATP .
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16 - various dicarboxylates ( alpha ketoglutarate , succinate and malate ) and a tricarboxylate ( citrate ) are rapidly oxidised by muscle tissue during respiration.
this statement is true .
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17 - which citric acid cycle intermediate can be used for the synthesis of porphyrins ?
a - succinate
b- succinyl co A
c- fumarate
d- malate
answer is b .
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18 - which possess the enzymes that mediate the net conversion of acetyl co A to oxaloacetate , which can be used for gluconeogenesis .
answer is PLANTS OR GLYOXYSOMES .
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19 - Which is the cofactor that is the substrate for E 3 and is reduced by FADH2?
Answer is NAD+
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20 - The citric acid cycle acts as a multistep catalyst that can oxidize an unlimited number of ______ groups ?
answer is acetyl groups .
TO VIEW THE CITRIC ACID CYCLE CLICK HERE
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answer is CITRATE SYNTHASE .
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12 - The molecule which inhibits isocitrate dehydrogenase ?
answer is CALCIUM . Ca +2.
-------------------------------------------------------------------------------------------
13 - this molecule regulates the citric acid cycle at many points , including the activation of pyruvate dehydrogenase phosphatase , isocitrate dehydrogenase and alpha ketoglutarate dehydrogenase .
answer is SERINE .
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14 - In e coli , this enzyme is inactivated by the phosphorylation of a serine residue in the active site ?
answer is isocitrate dehydrogenase .
----------------------------------------------------------------------------------------------------
15 - covalent modification of E 1 occurs by the specific phosphorylation of WHICH residue in a reaction catalysed by pyruvate dehydrogenase kinase ?
answer is ATP .
----------------------------------------------------------------------------------------------------------
16 - various dicarboxylates ( alpha ketoglutarate , succinate and malate ) and a tricarboxylate ( citrate ) are rapidly oxidised by muscle tissue during respiration.
this statement is true .
----------------------------------------------------------------------------------------------------------
17 - which citric acid cycle intermediate can be used for the synthesis of porphyrins ?
a - succinate
b- succinyl co A
c- fumarate
d- malate
answer is b .
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18 - which possess the enzymes that mediate the net conversion of acetyl co A to oxaloacetate , which can be used for gluconeogenesis .
answer is PLANTS OR GLYOXYSOMES .
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19 - Which is the cofactor that is the substrate for E 3 and is reduced by FADH2?
Answer is NAD+
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20 - The citric acid cycle acts as a multistep catalyst that can oxidize an unlimited number of ______ groups ?
answer is acetyl groups .
TO VIEW THE CITRIC ACID CYCLE CLICK HERE
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