98 - Thiamine pyrophosphate , functions as an ________ sink that acts to stabilize the carbon ion adduct formed during the decarboxylation of pyruvate .
answer is electron sink .
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99 - phosphoglycerate kinase converts 1 , 3 bisphosphoglycerate to 3 phosphoglycerate and forms an ATP .
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100 - the irreversible rate determining step in glycolysis is catalysed by ?
answer is PFK .
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101 - pentose phosphate pathway is also called hexose monophosphate shunt .
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102 - the molecule which conserves the free energy of metabolite oxidation for ATP synthesis ?
NADH .
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103 - The molecule which conserves the free energy of metabolite oxidation for reductive biosynthesis ?
NADPH .
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104 - 6 phosphogluconolactonase ------- 6 - phosphogluconate
6 phosphogluconate dehydrogenase ------------ RU5P
glucose 6 phosphate dehdrogenase -------- first committed step in HMP pathway
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105 - The process of fermentation has greater thermodynamic efficacy under physiological conditions than under standard biochemical conditions ?
the above statement is true .
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106 - under aerobic conditions glucose is oxidised during glycolysis and the coenzyme _________ is reduced and subsequently oxidised in a process known as electron transport ?
NAD +
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107 - in muscle a 10 % decrease in ATP concentration , results in a 100 % increase in ADP concentration and 400 % increase in AMP concentration .
true .
TO READ COMPLETELY ABOUT GLYCOLYSIS CLICK HERE
TO KNOW MORE ABOUT HMP SHUNT CLICK HERE
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Showing posts with label HMP shunt. Show all posts
Showing posts with label HMP shunt. Show all posts
Tuesday, January 8, 2008
12 - biochemistry mcqs - 87 to 97 - glycolysis
87 - lactose build up in the muscle during vigorous activity causes muscle fatigue and soreness .
the above statement is false . it is glycolytically generated acid that causes muscle fatigue and soreness .
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88 - when NADPH is needed from the pentose phosphate pathway , excess ________ is converted to glycolytic intermediates by a sequence of reactions which can operate in reverse .
ribulose - 5 - phosphate .
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89 - which state of PFK , does AMP preferentially bind ?
a- to the R state
b- to the T state
c- to both states without any preference
d- to neither
answer is a . to the R state .
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90 - yeast alcohol dehydrogenase and mammalian liver alcohol dehydrogenase , both require ____
a- Mg + 2
b- Zn + 2
c- calcium
d- iron
answer is b . ZINC .
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91 - glyceraldehyde 3 phosphate is phosphorylated to produce 1 , 3 bisphosphoglycerate to produce one molecule of NADH in the presence of the enzyme GA3P dehydrogenase .
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92 - alcoholic fermentation results in the regenration of NAD + along with the conversion of pyruvate to _______ and CO2 .
answer is ethanol.
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93 - the deficiency of which vitamine results in a condition called beri beri ?
thiamine is the answer .
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94 - transketolase has a thiamine pyrophosphate cofactor and catalyses the transfer of a c2 unit from XU5P to R5P .
true .
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95 - the three products of glycolysis are ATP , NADH and pyruvate .
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96 - what does ATP do to PFK , at high concentrations?
- it acts as an allosteric inhibitor , by binding to the T state .
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97 - the level of available ______, regulates hemoglobin's oxygen affinity ?
answer is 2 ,3 BPG.
TO READ COMPLETELY ABOUT GLYCOLYSIS CLICK HERE
TO KNOW MORE ABOUT HMP SHUNT CLICK HERE
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the above statement is false . it is glycolytically generated acid that causes muscle fatigue and soreness .
----------------------------------------------------------------------------
88 - when NADPH is needed from the pentose phosphate pathway , excess ________ is converted to glycolytic intermediates by a sequence of reactions which can operate in reverse .
ribulose - 5 - phosphate .
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89 - which state of PFK , does AMP preferentially bind ?
a- to the R state
b- to the T state
c- to both states without any preference
d- to neither
answer is a . to the R state .
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90 - yeast alcohol dehydrogenase and mammalian liver alcohol dehydrogenase , both require ____
a- Mg + 2
b- Zn + 2
c- calcium
d- iron
answer is b . ZINC .
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91 - glyceraldehyde 3 phosphate is phosphorylated to produce 1 , 3 bisphosphoglycerate to produce one molecule of NADH in the presence of the enzyme GA3P dehydrogenase .
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92 - alcoholic fermentation results in the regenration of NAD + along with the conversion of pyruvate to _______ and CO2 .
answer is ethanol.
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93 - the deficiency of which vitamine results in a condition called beri beri ?
thiamine is the answer .
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94 - transketolase has a thiamine pyrophosphate cofactor and catalyses the transfer of a c2 unit from XU5P to R5P .
true .
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95 - the three products of glycolysis are ATP , NADH and pyruvate .
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96 - what does ATP do to PFK , at high concentrations?
- it acts as an allosteric inhibitor , by binding to the T state .
---------------------------------------------------------------------------------------
97 - the level of available ______, regulates hemoglobin's oxygen affinity ?
answer is 2 ,3 BPG.
TO READ COMPLETELY ABOUT GLYCOLYSIS CLICK HERE
TO KNOW MORE ABOUT HMP SHUNT CLICK HERE
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11 - biochemistry mcqs - 76 to 86 - glycolysis
76 - an enzyme that transfers phosphoryl groups between ATP and a metabolite ?
a- kinase
b- aldolase
c- enolase
d- mutase
answer is a .
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77 - the ion essential for kinase activity ?
answer - magnesium .
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78 - the enzyme which catalyses the transfer of a functional group from one position to other ?
a- mutase
b- enolase
c- aldolase
d- kinase
answer is a . mutase . phosphoglycero mutase converts the 3 phosphoglycerate to 2 phosphoglycerate .
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79 - compounds with high phosphoryl group transfer potentials are formed during glycolysis .
the above statement is true .
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80 - when the need for ribose 5 phosphate exceeds that of NADPH , reversal of the transaldolase and transketolase reactions , diverts ribose 5 phosphate from the glycolytic pathway .
the above statement is true .
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81 - after phosphorylation , galactose reacts with the UDPG to form glucose 1 phosphate and ___________ before an epimerization reaction ?
answer is UDP - GALACTOSE
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82 - fructose metabolism in muscle requires only one step before it can enter into glycolysis ?
the above statement is true .
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83 - it has been demonstrated that triose phosphate isomerase has a reaction rate that is diffusion controlled and is therefore an example an enzyme that has reached catalytic perfection ?
the above statement is true .
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84 - enolase catalyses a reaction that results in the formation of a high energy intermediate .
the above statement is true . the enzyme enolase catalyses the conversion of the 2 - phosphoglycerate to phosphoenolpyruvate .
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85 - the statement which describes glycolysis stage II , the stage of energy recovery are ?
answer is --- two molecules of glyceraldehyde 3 phosphate are converted to pyruvate and four molecules of ATP are generated .
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86 - ribulose 5 phosphate is converted to xylulose 5 phosphate by the action of the enzyme ?
a- isomerase
b- epimerase
c- kinase
d- aldolase
answer is b .
TO READ COMPLETELY ABOUT GLYCOLYSIS CLICK HERE
TO KNOW MORE ABOUT HMP SHUNT CLICK HERE
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a- kinase
b- aldolase
c- enolase
d- mutase
answer is a .
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77 - the ion essential for kinase activity ?
answer - magnesium .
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78 - the enzyme which catalyses the transfer of a functional group from one position to other ?
a- mutase
b- enolase
c- aldolase
d- kinase
answer is a . mutase . phosphoglycero mutase converts the 3 phosphoglycerate to 2 phosphoglycerate .
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79 - compounds with high phosphoryl group transfer potentials are formed during glycolysis .
the above statement is true .
----------------------------------------------------------------------------------
80 - when the need for ribose 5 phosphate exceeds that of NADPH , reversal of the transaldolase and transketolase reactions , diverts ribose 5 phosphate from the glycolytic pathway .
the above statement is true .
---------------------------------------------------------------------------------
81 - after phosphorylation , galactose reacts with the UDPG to form glucose 1 phosphate and ___________ before an epimerization reaction ?
answer is UDP - GALACTOSE
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82 - fructose metabolism in muscle requires only one step before it can enter into glycolysis ?
the above statement is true .
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83 - it has been demonstrated that triose phosphate isomerase has a reaction rate that is diffusion controlled and is therefore an example an enzyme that has reached catalytic perfection ?
the above statement is true .
------------------------------------------------------------------------------
84 - enolase catalyses a reaction that results in the formation of a high energy intermediate .
the above statement is true . the enzyme enolase catalyses the conversion of the 2 - phosphoglycerate to phosphoenolpyruvate .
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85 - the statement which describes glycolysis stage II , the stage of energy recovery are ?
answer is --- two molecules of glyceraldehyde 3 phosphate are converted to pyruvate and four molecules of ATP are generated .
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86 - ribulose 5 phosphate is converted to xylulose 5 phosphate by the action of the enzyme ?
a- isomerase
b- epimerase
c- kinase
d- aldolase
answer is b .
TO READ COMPLETELY ABOUT GLYCOLYSIS CLICK HERE
TO KNOW MORE ABOUT HMP SHUNT CLICK HERE
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10 - HMP shunt or pentose phosphate pathway
CLICK ON THE IMAGE FOR A BIGGER IMAGE .The main purpose of the pentose phosphate pathway is to regenerate NADPH from NADP+ through an oxidation/ reduction reaction. This reaction is coupled to the formation of ribose 5-phosphate from glucose 6-phosphate. NADPH is used for reductive reactions in anabolism, especially in fatty acid synthesis. In red blood cells, the major role of NADPH is to reduce the disulfide form of glutathione to the sulfhydryl form. The reduced glutathione is pertinent for maintaining the normal structure of red blood cells and for keeping hemoglobin in the ferrous state [Fe(II)]. The nonoxidative portion of the pathway creates carbon chain molecules ranging from 3 to 7 carbons. These compounds are intermediates in glycolysis and gluconeogenesis or other biosynthetic processes. The pentose phosphate pathway primarily produces NADPH, ribose 5-phosphate, fructose 6-phosphate, and glyceraldehyde 3-phosphate.
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