18 - biochemistry mcqs - 154 to 155

154) True about Heparin is

a. Basic in nature

b. Contains Glucronic Acid

c. LMW Heparin selectively inhibit Xa

d. no effect on platelet

Answer : c) LMW Heparin selectively inhibit Xa

Reference: Chaterjee 6^th Edition Page 39

155) About PGE₂

a. Synthesized in fetus

b. Closes the ductus arteriosus

c. Both

d. None

Answer : b) Closes the ductus arteriosus

Reference: Tripathi 5^th Edition Page 159

17 - biochemistry mcqs - 143 to 153

143) Urea synthesized mainly in

a. Liver

b. Heart

c. Kidney

d. brain

Answer : Liver

Reference: Chaterjee 6^th Edition Page 411

144) The End product of purine metabolism is

a. Urea

b. Creatinine

c. Uric Acid

d. GLycine

Answer : c) Uric Acid

Reference: Chaterjee 6^th Edition Page 212

145) Folic acid antagonist for Cancer is

a. Methotrxate

b. Vincristine

c. Cyclosporine

d. Azathioprine

Answer : a) Methotraxate

Reference: Tripathi 5^th Edition Page 772

146) In Galactosemia the Cataract is due to the production of

a. Sorbital

b. Galactose

c. Glucose

d. Galactositol

Answer : d) Galactositol

Reference: Chaterjee 6^th Edition Page 312

147) Following are causes of Vitamin B 12 deficiency except

a. Strict vegetarian

b. Blind loop Syndrome

c. Diphyllobothrium latum infection

d. Chronic Blood loss

Answer :D) Chronic Blood Loss

Reference: Chaterjee 6^th Edition Page 182

148) Hyaluronic acid is made up of

a. N-Acetyl Glusosamine

b. D- GLucuronic Acid

c. Both

d. None

Answer : C) Both

Reference: Chaterjee 6^th Edition Page 38

149) Fluoride inhibits

a. enolase

b. Glukokinase

c. Aldolase

d. Phosphofructokinase

Answer : a) Enolase

Reference: harper 24^th Edition Page 178

150) Thiamine rich in

a. Unpolished rice

b. Fish

c. Soyabean

d. All of these

Answer : a) Unpolished rice

Reference: Chaterjee 6^th Edition Page 159

151) The initial change seen in Hyperventilation regarding PCO₂ is

a. No changes

b. Increased PCO₂ with increased pH

c. Normal PCO₂ with increased pH

d. Decreased PCO₂ with increased pH

Answer : d) Decreased PCO2 with increased pH

Reference: Chaterjee 6^th Edition Page

152) Characteristics of Insulin resistant syndrome all except

a. Hypoglycemia

b. May be associated with PCOD

c. Obesity

d. Hyperglycemia

Answer : Hypoglycemia

Reference: Harrison 15^th Edition Chapter 77

153) FSH and LH are Produced by

a. Anterior pituitary

b. Hypothalamus

c. Placenta

d. Ovary

Answer : A) Anterior Pituitary

Reference: Ganong 22^nd Edition Page 397

16 - biochemistry mcqs - 132 to 142

132) Vitamin useful in the treatment of Hartnup’s disease is

a. Biotin

b. Niacin

c. Folic Acid

d. Thiamine

Answer : b) Niacin

Reference: Harrison 15^th Edition Chapter 353

133) Ketogenic amino acid

a. Leucine

b. Valine

c. Alanine

d. Tryptophan

Answer : Leucine

Reference: harper 24^th Edition Page 310

134) Maple Syrup Urine Disease is due to defect in the metabolism of

a. Unbranched aminoacid

b. Phenyl alanine

c. Branched Chain Amino Acid

d. Tyrosine

Answer : c) Branched Chain Amino Acid

Reference: Chaterjee 6^th Edition Page 456

135) Why muscle glycogen is not useful in elevation of Glucose level of blood because muscle does not contain

a. Glucose – 6 – phosphatase

b. Phosphorylase

c. Cyclic AMP

d. Protein Kinase

Answer : a) Glucose – 6 – phosphatase

Reference: Chaterjee 6^th Edition Page 291

136) Irreversible enzyme step all except –

a. phosphofructokinase

b. Phosphohexose isomerase

c. hexokinase

d. Pyruvate kinase

Answer : B) Phosphohexose isomerase

Reference: Chaterjee 6^th Edition Page 306

137) NADPH not produced for fatty acid synthesis from

a. HMP shunt

b. malic enzyme

c. lactic dehydrogenase

d. isocitrate dehydrogenase

Answer : c) lactic dehydrogenase

Reference: Chaterjee 6^th Edition Page 355

138) The main role of Vitamin K is

a. Carboxylation

b. Formatiuon of active succinate

c. Heme systhessis

d. Synthesis of Fatty acid

Answer : a) Carboxylation

Reference: Chaterjee 6^th Edition Page 155

139) Enterohepatic circulation of bile salt is affected and that leads to

a. Vitamin K deficiency

b. Hypertension

c. Hemolytic anemia

d. Diabetes Insipidus

Answer : a) Hemolytic Anemia

Reference: Chaterjee 6^th Edition Page 155

140) Bile salts is produced from

a. Cholesterol

b. Amino acids

c. Glycogen

d. Lecithin

Answer : a) Cholesterol

Reference: Ganong 22^nd Edition Page 501

141) Vitamin K deficiency occurs in

a. Obstructive Jaundice

b. Hemolytic Jaundice

c. Prehepatic Jaundice

d. Secondaries liver

Answer : a) Obstructive Jaundice

Reference: Chaterjee 6^th Edition Page 155

142) Antiracchitic Vitamin D is activated in the following organ

a. Muscle

b. Lungs

c. Kidney

d. Intestine

Answer : c) Kidney

Reference: Ganong 22^nd Edition Page 388

13 - biochemistry mcqs - 98 TO 107 - glycolysis

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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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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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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8 - biochemistry mcqs - 54 to 64 - glycolysis

54- in glycolysis ?

ans- glucose is converted inot 2 molecules of pyruvate by the synthesis of two NADH and 2 ATP molecules and utilisation of 2ATP molecules too .

- i dont wanna give u choices in this question because it confuses u a lot , so stick to the above statement .

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55 - the compound which reduces the affinity of pyruvate kinase for its substrate ?

a- phosphoenol pyruvate
b- pyruvate
c- NADH
d- ATP

answer is ATP .

The pyruvate kinase converts phosphoenol pyruvate to pyruvate and in this reaction ATP is synthesized .

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56 - in muscle , glycolytic flux is subject to regulation by substrate cycling .

the above statement is true .

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57 - a deficiency of type B aldolase , results in __________ intolerance , a self limiting genetic disease ?

a- fructose intolerance
b- glucose intolerance
c- galactose intolerance
d- ribose intolerance

the answer is a .

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58 - the isomerisation of glucose-6-phosphate to fructose-6-phosphate is catalysed by which enzyme ?

a- hexokinase
b- glucokinase
c- phosphoglucose isomerase
d- phosphofructo kinase

answer is c . phosphoglucose isomerase.

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59 - the glyceraldehyde 3 phosphate dehydrogenase reaction is exergonic and will therefore proceed in the forward direction ?

the above statement is false . the glyceraldehyde 3 phosphate dehydrogenase reaction is slightly endergonic , but is pulled forward by the subsequent reaction of phosphoglycerate kinase . phosphoglycerate kinase converts 1 , 3 bisphosphoglycerate to 3 phosphoglycerate .

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60 - the rate of NADPH production is controlled by the rate of glucose-6-phosphate dehydrogenase reaction .

the above statement is true .

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61 - the exclusion of water from the active site of hexokinase is responsible for preventing the hydrolysis of ATP from being the dominant reaction during catalysis .

the above statement is true .

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62 - phosphoglycerate kinase catalyses a step in glycolysis , which results in the formation of ATP .

the above statement is true . the enzyme phosphoglycerate kinase catalyses the conversion of 1 , 3 bisphosphoglycerate to 3 phosphoglycerate to produce one ATP .

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63 - The hexokinase has very low affinity for hexoses .

the statement is true .

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64 - in two steps mannose is converted to ______, to enter into the glycolytic pathway ?

a- fructose 6 phosphate
b- glucose 6 phosphate
c- fructose
d- glucose

answer is a .


TO READ COMPLETELY ABOUT GLYCOLYSIS CLICK HERE

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6 - biochemistry mcqs - 41 to 53 - citric acid cycle

41 - the most crucial regulators of the citric acid cycle are its substrates , acetyl co A and oxaloacetate , and its product , NADH .

the above statement is true .

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42 - which enzyme of the citric acid cycle is very similar structurally and mechanistically to lactate dehydrogenase and alcohol dehydrogenase ?

a- alpha ketoglutarate dehydrogenase
b- succinate dehydrogenase
c- NAD + dependent isocitrate dehydrogenase
d- malate dehydrogenase

answer is d .

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43 - the thiamine pyrophosphate ( TPP ) a cofactor is bound to E1 and decarboxylates pyruvate , yielding a hydroxyethyl TPP carbon ion .

the above statement is true .

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44 - several biosynthetic pathways use citric acid cycle intermediates as starting material for anabolic reactions .

the above statement is true .

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45 - lipoamide consists of lipoic acid covalently joined to the epsilon - amino group of a lysine residue via an amide bond .

the above statement is true .

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46 - how is flux through out the citric acid controlled ?

a- primarily by control of citrate synthase
b- primarily by control of isocitrate dehydrogenase
c- primarily by control of alpha ketoglutarate dehydrogenase
d- at many points , including all the above

answer is d .

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47 - alpha ketoglutarate dehydrogenase is a multienzyme complex containing alpha ketoglutarate dehydrogenase ( E 1 ) , dihydro lipoyl trans succinylase ( E2 ) and dihydro lipoyl dehydrogenase .

the above statement is true .

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48 - in pyruvate dehydrogenase which cofactor is used to decarboxylate pyruvate?

a- TPP
b- lipoic acid
c- co A
d- FAD

the answer is a .

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49 - describe the regulatio of the conversion of isocitrate to alpha keto glutarate ?

a- calcium and ADP stimulate , NADH AND ATP inhibit .

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50 - Isocitrate lyase and malate sythase occur in both plants and animals .

the above statement is false . these enzymes occur only in plants .

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51 - acetyl co A is formed from pyruvate through oxidative decarboxylation by a multienzyme complex named ?

answer is pyruvate dehydrogenase .

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52 - which three compounds associated with the citric acid cycle inhibit their own synthesis ?

answer is acetyl co A , citrate and succinyl co A .

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53 - the tight coupling of oxygen consumption , NADH reoxidation and ATP production in the citric acid cycle requires regulation by feedback mechanisms that coordinate NADH Production with energy expenditure .

true.

TO VIEW THE CITRIC ACID CYCLE CLICK HERE

5 - biochemistry mcqs - 31 to 40 - citric acid cycle

31 - for every NADH that passes its electrons on to the electron transport chain , approximately how many ATP are produced from the ADP and phosphate ?

answer is 3.

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32 - isocitrate lyase cleaves isocitrate to succinate and __________ in the glyoxylate pathway ?

answer is glyoxylate .

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33 - in a net reaction of the citric acid cycle , what are the reactants ?

answer is ---------- 3 NAD + plus FAD plus GDP plus PHOSPHATE plus acetyl co A .

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34 - which segment of the citric acid cycle is used in the glyoxylate pathway ?

answer is succinate to oxaloacetate .

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35 - gluconeogenesis takes place in the cytosol and the oxaloacetate must be converted for transport out of the mitochondrion .

the above statement is true .

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36 - which substrate in the citric acid cycle is coupled to the reduction of FAD to FADH2 ?

a- citrate
b- isocitrate
c- succinate
d- fumarate

answer is c .

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37 - which enzyme complex of e coli is a particle of about 4600 kD , with a diameter of 300 .

answer is pyruvate dehydrogenase .

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38 - when glucose is converted to lactate or ethanol , a relatively reduced product leaves the cell.

the above statement is true .

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39 - albert szent - gyorgyi found that cellular respiration is dramatically decreased by small amounts of succinate , fumarate , malate or oxaloacetate .

the above statement is false . the cellular respiration actually increases after adding these compounds .

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40 - the biosynthesis of which compounds uses the alpha ketoglutarate and oxaloacetate as starting materials ?

answer is amino acid biosynthesis .


TO VIEW THE CITRIC ACID CYCLE CLICK HERE

4 - biochemistry mcqs - 21 to 30 - citric acid cycle

21 - the enzyme of the citric acid cycle that is inhibited by NADH ?

Answer is citrate synthase .

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22 - which citric acid cycle intermediates can be used for the synthesis of amino acids and can be regenerated by the same amino acids ?

a- succinyl co A and succinate
b- succinate and fumarate
c- malate and oxaloacetate
d- alpha ketogluatarate and oxaloacetate .

the correct answer is d . alpha ketoglutarate and oxaloacetate .

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23 - what is formed in a second concerted acid - base catalysed step of citrate synthase , in which the acetyl co A enol attacks oxaloacetate ?

answer is citryl co A .

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24 - which is the thiamine pyro phosphate requiring enzyme that decarboxylates pyruvate with the formation of a hydroxyethyl - TPP intermediate ?

answer is pyruvate dehydrogenase .

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25 - what is the name of the catalytically inactive E2 like protein existing in six copies that may help bind E3 to the complex .

answer is PROTEIN X .

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26 - What is the name of the cofactor that is bound to E3 and is reduced by lipoamide?

answer is FAD.

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27 - this cofactor accepts the acetyl group from the lipoamide in the pyruvate dehydrogenase complex ?

answer is coenzyme A .

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28 - This reaction is catalysed by E 3 , in which an acetyl group is transfered to co A , yielding acetyl co A and dihydrolipoamide E2 .

answer is TRANSESTERIFICATION .

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29 - Oxaloacetate undergoes transamination with alanine to produce what ?

a- glutamate and pyruvate
b- glutamate and alpha keto glutarate
c- aspartate and pyruvate
d- aspartate and alpha ketoglutarate

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30 - which enzyme produces the second CO 2 and NADH of the citric acid cycle ?

answer is alpha ketoglutarate dehydrogenase .

TO VIEW THE CITRIC ACID CYCLE CLICK HERE

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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