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CBSE Questions for Class 11 Medical Biology Respiration In Plants Quiz 11 - MCQExams.com
CBSE
Class 11 Medical Biology
Respiration In Plants
Quiz 11
Which one is absent in erythrocytes?
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Krebs cycle
0%
Enzymes
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Biomembrane
0%
Hyaloplasm
Explanation
Erythrocytes as they mature lose a number of organelles including mitochondria. As Krebs' cycle occurs in mitochondria, it is absent in erythrocytes. RBCs predominantly use HMP for respiration.
So, the correct answer is 'Krebs' cycle'.
Cofactor required for formation of acetyl CoA is _____________.
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TPP
0%
Lipoic acid
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$$Mg^{2+}$$, CoA
0%
All the above
Conversion of sugar into alcohol during fermentation is due to direct action of
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Temperature
0%
Concentration of sugar
0%
Zymase
0%
Microorganisms
Explanation
Conversion of sugar to alcohol directly was found in yeast fermentation in which glucose was converted to ethyl alcohol and CO$$_2$$. The conversion happens in presence of an enzyme called zymase which is found naturally in yeast. So, the answer is 'Zymase'.
Which of the following enzymes is absent in mitochondria?
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Aconitase
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Malic dehydrogenase
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Fumarase
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Hexokinase
Number of carbon atoms available in acetyl CoA is ____________.
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6
0%
4
0%
3
0%
2
How many ATP is produced in the pay off phase of glycolysis?
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0%
1
0%
5
0%
4
0%
6
Explanation
Glycolysis is a metabolic process in which one glucose molecule is converted into 2 puruvate molecules under aerobic condition. During the formation of 3-phosphoglyceric acid and pyruvic acids 2 ATP molecules are formed respectively. However, 2 molecules of ATP are utilized during conversion of glucose to glucose-6-phosphate and fructose-6-phosphate to fructose-1,6-biphosphate. Hence, the end products of glycolysis are 2 ATP molecules, 2 pyruvic acid molecules and 2 NADH molecules.
Thus, the correct answer is '4.'
Decline in activity of enzyme hexokinase by glucose 6-phosphate is caused by
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Non-competitive inhibition
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Competitive inhibition
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Allosteric modulator
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Denaturation of enzyme
Explanation
Hexokinase is a regulatory enzyme which catalyses the entry of glucose into glycolytic pathway. The enzyme catalyses the conversion of glucose into glucose-6-phosphate. Hexokinase has high affinity for glucose. the hexokinase is allosterically inhibited by its own product which is glucose-6-phosphate. When the concentration of glucose-6-phosphate increases, it binds with the enzyme at its allosteric site and brings about the conformational change in the enzyme. Due to this enzyme can no longer bind to the glucose and the forward reaction is inhibited. Such type of inhibition is known as feedback inhibition.
Thus, the correct answer is option B.
Alcoholic fermentation is carried out by
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Saccharomyces.
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Lactobacillus.
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Clostridium.
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Aspergillus.
Explanation
Saccharomyces is used in fermentation is alcohol. Saccharomyces will be grown in anaerobic conditions same as growth takes place in aerobic conditions.
So the correct option is 'Saccharomyces.'
Component of ETC of mitochondria is
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Carotenoids
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Plastocyanin
0%
Phytochrome
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Cytochrome oxidase
Explanation
ETC or Electron transport chain is a stepwise process of electron transfer that carries out final oxidation to produce energy as ATP. One of the related enzymes in ETC is cytochrome oxidase which forms a complex and carries electrons down the energy levels. The released energy is in the form of ATP.
So, the answer is 'Cytochrome oxidase'.
Energy required to form glucose from pyruvate is equivalent to
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32 ATP
0%
16 ATP
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8 ATP
0%
4 ATP
Explanation
Glucose is converted to pyruvic acid through glycolysis. There is a net yield of 8 ATP for 1 glucose to undergo glycolysis. So if the pyruvic acid is converted to glucose, the energy required will also be 8 ATP. So the answer is '8 ATP'.
Sequence of organic acids in Krebs cycle is
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Citric acid oxalosuccinic acid isocitric acid
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Citric acid isocitric acid oxalosuccinic acid
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Isocitric acid oxalosuccinic acid citric acid
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Oxalosuccinic acid isocitric acid citric acid
Explanation
Krebs' cycle starts with the formation of citric acid which then converts to cis-aconitic acid and then to iso-citric acid in presence of aconitase . Iso-citric acid converts to oxalosuccinic acid in presence of
isocitrate dehydrogenase.
So the answer is 'Citric acid isocitric acid oxalosuccinic acid'.
Select the correct match for the following :
a) Net ATP produced in glycolysis
b) Positive Benedicts test
c) Genes unable to express in presence of their alleles
d) A character controlled by many genes
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36, glucose, recessive, polygenic
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8, glucose, recessive, polygenic
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32, sucrose, recessive, polygenic
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8, fructose, dominant, polygenic
Enzymes of Krebs cycle occur in mitochondrial matrix except one which is attached to inner mitochondrial membrane
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Citrate synthetase
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keto glutarate dehydrogenase
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Succinate dehydrogenase
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Malate dehydrogenase
Explanation
Glycolysis is followed by Krebs' cycle which occurs in mitochondria. Almost the entire process occurs in the mitochondrial matrix except succinate dehydrogenase, an enzyme that converts succinic acid to fumaric acid. This enzyme is present in the inner membrane of mitochondria.
So the answer is 'Succinate dehydrogenase'.
What is true for Krebs cycle?
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ATP / GTP is formed
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Two decarboxylations
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Acetyl CoA combines with OAA
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All of the above.
Explanation
Pyruvate formed from glycolysis enter into Krebs cycle and yields high-energy molecules of NADH and FADH as well as some ATP. Each three-carbon pyruvic acid molecule undergoes conversion to a substance called acetyl-coenzyme A, or acetyl-CoA.
So the correct option 'ATP/GTP is formed, two decarboxylations, acetyl CoA combines with OAA.'
A sudden change from anaerobic to aerobic process produces ________________.
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Pasteur effect
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Emerson effect
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Blackmans law
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Chargaffs rule
Explanation
Answer is option A i.e. "Pasteur effect"
Pasteur effect is exhibited in yeast cells during anaerobic fermentation. Pasteur effect influences the rate of glycolysis and occurs in presence of oxygen which decreases the rate of sugar breakdown in yeast.
While, Blackman's law and Emerson effect is related to determining the rate of photosynthesis. Chargraff's rule is a rule for base equivalence in DNA.
At the end of citric acid cycle most of the energy is transferred to
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NADH and FADH$$_2$$.
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Oxaloacetic acid.
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Citric acid.
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ATP.
Explanation
For one glucose molecule, Citric acid cycle produces reduced electron carriers, 8 molecules of NADH and 2 molecules of FADH$$_2$$.
So the correct option is 'NADH and FADH$$_2$$.'
RQ is more than one indicating
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Aerobic respiration.
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Anaerobic respiration.
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Both A and B.
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None of the above.
Explanation
If RQ value is more than 1, the respiration would be aerobic and anaerobic respiration.
So the correct option is 'Aerobic respiration and Anaerobic respiration'.
Two names referring to same thing
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Krebs cycle and Calvin cycle.
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Tricarboxylic acid cycle and citric acid cycle.
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Citric acid cycle and Calvin cycle.
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Tricarboxylic acid cycle and urea cycle.
Explanation
Krebs cycle also called the Citric acid cycle or Tricarboxylic acid cycle.
So the correct option is 'Tricarboxylic acid cycle and citric acid cycle.'
Mechanism of aerobic respiration / tricarboxylic acid pathway was discovered by
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Calvin.
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Krebs.
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Pasteur.
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Hatch and Slack.
Explanation
The tricarboxylic acid pathway is also called as the Citric acid cycle is discovered by British biochemist Sir Hans Krebs.
So the correct option is 'Krebs.'
R.Q. of anaerobic respiration is
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Zero
0%
Less than 1
0%
1
0%
More than 1
Explanation
The utilization of oxygen is nill in anaerobic respiration. Hence the R.Q. value is infinity.
So the correct option is 'More than 1.'
Pasteur effect is __________________.
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Stoppage of fermentation in presence of oxygen
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Increase of fermentation in presence of oxygen
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Decrease in fermentation in presence of oxygen
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No effect on fermentation
A single turn of citric acid cycle yields _________________.
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$$2 FADH_2, 2NADH_2, 2 GTP$$
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$$1 FADH_2, 2NADH_2, 1 GTP$$
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$$1 FADH_2, 3NADH_2, 1 GTP$$
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$$FADH_2, 4NADH_2, 1 GTP$$
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$$1 FADH_2, 1NADH_2, 2 GTP$$
Number of oxygen molecules required during glycolysis of one glucose molecule is
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0%
38
0%
36
0%
2
0%
Zero
Explanation
Glycolysis of one glucose molecule produces two molecules of pyruvic acid as the end product. However, during each oxidative step, no molecular oxygen is required as such. Oxidation occurs by removal of hydrogen and not addition of oxygen.
So the answer is 'Zero'.
Respiratory quotient (R.Q.) is
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Volume of O$$_2$$ evolved / Volume of CO$$_2$$ consumed
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Volume of CO$$_2$$ evolved / Volume of O$$_2$$ consumed
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Volume of O$$_2$$ consumed / Volume of CO$$_2$$ evolved
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Volume of CO$$_2$$ consumed / Volume of O$$_2$$ evolved
Explanation
Respiratory quotient or R.Q. is the ratio of volume of CO$$_2$$ produced to volume of O$$_2$$ consumed during cellular respiration. It is measured by Ganong's Respirometer. R.Q. for carbohydrates is 1, organic acid is >1 and fats and proteins is <1.
So, the correct answer is 'Volume of CO$$_2$$ evolved / Volume of O$$_2$$ consumed'.
How many ATP is utilized in the preparatory phase of glycolysis?
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7
0%
4
0%
2
0%
5
Explanation
Glycolysis is a metabolic process in which one glucose molecule is converted into 2 puruvate molecules under aerobic condition. During the formation of 3-phosphoglyceric acid and pyruvic acids 2 ATP molecules are formed respectively. However, 2 molecules of ATP are utilized during conversion of glucose to glucose-6-phosphate and fructose-6-phosphate to fructose-1,6-biphosphate. Hence, the end products of glycolysis are 2 ATP molecules, 2 pyruvic acid molecules and 2 NADH molecules.
Thus, the correct answer is '2.'
Pasteur effect can be studied in case of __________.
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Nostoc
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Penicillium
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Pinnularia
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Saccharomyces
Enzyme used in conversion of glucose into glucose 6-phosphate is
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Hexokinase
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Isomerase
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Phosphokinase
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Phosphohexokinase
Explanation
Glucose is a 6 carbon organic substrate that undergoes glycolysis for the release of energy during cellular respiration. Glucose is first phosphorylated to glucose 6-phosphate by an enzyme called 'Hexokinase' in the presence of Mg2+. So, the answer is 'Hexokinase'.
A value of RQ less than one means
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Carbohydrates are used as respiratory material.
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Organic acids are used as respiratory substances.
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Oxidation of respiratory substrate consume more O$$_2$$ than CO$$_2$$ released.
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Oxidation of respiratory substrate consume less O$$_2$$ than CO$$_2$$ released The reaction is anaerobic.
Explanation
When the RQ value is less than one for fats, as fats consume more oxygen for respiration than carbohydrates.
So the correct option is 'Oxidation of respiratory substrate consume more O2 than CO2 released.'
Alcoholic fermentation occurs in the presence of
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Zymase.
0%
Amylase.
0%
Invertase.
0%
Maltase.
Explanation
The fermentation process is catalyzed by enzyme Zymase which converts sugar to ethanol and carbon dioxide.
So the correct option is 'Zymase.'
For formation of ethanol, pyruvic acid is first changed to acetaldehyde by enzyme
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Pyruvate dehydrogenase
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Pyruvate decarboxylase
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Alcohol oxidase
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Alcohol dehydrogenase
Explanation
Alcoholic fermentation employs the conversion of pyruvic acid to ethanol for the release of energy. This is an incomplete oxidation in which aldehyde is first formed as an intermediate which is then further oxidised to alcohol. Pyruvic acid to acetaldehyde conversion is brought about by pyruvate decarboxylase which releases CO2.
So the answer is 'Pyruvate decarboxylase'.
Succinate + FAD forms
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Fumarate + $$FADH_2$$
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Malate + $$NADH_2$$
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Isocitrate + $$NADH_2$$
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Citrate + Water
Explanation
In Krebs' cycle, succinate is dehydrogenated to fumarate by the enzyme succinate dehydrogenase. The hydrogen that is released reduces FAD to FADH2.
So the answer is 'Fumarate + FADH2'.
Which is wrong about Krebs cycle?
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It occurs in mitochondria.
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It starts with 6 carbon compound.
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It is also called citric acid cycle.
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Glycolysis is linked to it through malic acid.
Explanation
Krebs cycle also called as citric acid cycle occurs in the mitochondrial matrix and starts with 6 carbon compound but not linked glycolysis through malic acid.
So the correct option is 'Glycolysis is linked to it through malic acid.'
Acetyl CoA forms a 6-C compound after combining with
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Malic acid
0%
Citric acid
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Succinic acid
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Oxaloacetic acid
Explanation
Pyruvic acid is converted to Acetyl CoA (2 C) by the link reaction through the pyruvate dehydrogenase complex. Acetyl CoA can now enter Krebs' cycle by combining with oxaloacetic acid which is a 4 carbon compound. So the citric acid that is formed is a 6 carbon compound.
So, the correct answer is 'Oxaloacetic acid'.
Reduction of
$$
NAD^+$$ does not occur in the reaction
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0%
Pyruvic acid Acetyl CoA
0%
Isocitric acid -ketoglutaric acid
0%
Malic acid Oxaloacetic acid
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Succinic acid Fumaric Acid
Explanation
Krebs' cycle is a cyclic process that occurs in mitochondrial matrix in which reduced compounds like NADH2 and FADH2 are formed that liberate energy as ATP as they undergo ETS. The conversion of succinic acid to fumaric acid reduces FAD to FADH2 and not NAD to NADH2.
So the answer is 'Succinic acid to Fumaric acid'.
Choose the correct labeling
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a. Ethanol
b. $$CO_2 $$
c. Acetaldehyde
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a. $$CO_2 $$
b. Acetaldehyde
c. Ethanol
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a. $$CO_2 $$
b. Ethanol
c. Acetaldehyde
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a. Ethanol
b. Acetaldehyde
c. $$CO_2 $$
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a. Acetaldehyde
b. $$CO_2$$
c. Ethanol
Explanation
In the fermentation process pyruvate is decarboxylated to an acetaldehyde releasing carbon dioxide and acetaldehyde is catalyzed by alcohol dehydrogenase to produce ethanol.
So, the correct option is 'Ethanol, Acetaldehyde, and CO$$_2$$.'
3-phosphoglyceraldehyde is oxidized in glycolysis to form
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1, 3-biphosphoglycerate
0%
3-phosphoglycerate
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2-phosphoglycerate
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Phosphophenol pyruvate
Explanation
Glycolysis is a metabolic process in which one glucose molecule is converted into 2 puruvate molecules under aerobic condition. During the sixth step, 3-phosphoglyceraldehyde is oxidized to 1,3-biphsosphoglycerate in presence of enzyme glyceraldehyde-3-phosphate dehydrogenase. During this reaction, NAD$$^+$$ is converted to NADH.
Thus, the correct answer is '
1, 3-biphosphoglycerate.'
Conversion of pyruvic acid to acetyl CoA is _______________.
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Reductive carboxylation
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Oxidative decarboxylation
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Oxidative carboxylation
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Reductive decarboxylation
Aerobic respiratory pathway is appropriate termed ___________.
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Anabolic
0%
Catabolic
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Amphibolic
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Parabolic
Pyruvate dehydrogenase complex needed for conversion of pyruvic acid to acetyl CoA is located in _______________.
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Intermembrane space
0%
Cytoplasm
0%
Matrix of mitochondria
0%
Grana of chloroplast
Pyruvic acid formed during glycolysis is oxidised to CO$$_2$$ and H$$_2$$O in
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0%
Calvin cycle.
0%
Hill reaction.
0%
Krebs cycle.
0%
Nitrogen cycle.
Explanation
During glycolysis process, glucose is broken down into two molecules of pyruvate and the pyruvate enters into the mitochondria where it is oxidized through the citric acid cycle to carbon dioxide and water.
So the correct option is 'Krebs cycle.'
R.Q. is one in case of
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Fatty acids
0%
Carbohydrates
0%
Nucleic acid
0%
Organic acids
Which of the following membrane bound complex in mitochondria is not a proton pump :-
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Cytochrome b, c
0%
Cytochrome c oxidase
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NADH dehydrogenase
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Succinate dehydrogenase
R.Q. would depend upon
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Nature of enzymes
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Nature of substrate
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Amount of CO$$_2$$ released
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Amount of O$$_2$$ utilised
Explanation
Respiratory Quotient (R.Q.) is the ratio of the volume of CO$$_{2}$$ released to the volume of O$$_{2}$$ consumed in a respiration process. It depends on the nature of the substrate and its capacity of using
O$$_{2}$$ and releasing
CO$$_{2}$$. For example, glucose consumes 6
CO$$_{2}$$ and releases 6
O$$_{2}$$, so its R.Q. is 1.
Hence, the correct answer is 'Nature of substrate'
In Krebs cycle, OAA accepts acetyl CoA to form
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0%
Citric acid
0%
Oxalosuccinate
0%
Fumarate
0%
Succinyl CoA
Explanation
Citric acid cycle is also called as Krebs cycle or tricarboxylic acid cycle. It is a metabolic cycle through which aerobic organisms obtain their energy. Pyruvate produced in glycolysis first gets converted into acetyl CoA before entering citric acid cycle. This acetyl CoA is accepted by oxaloacetic acid (OAA) to form ctric acid, the first product of the cycle.
Thus, the correct answer is 'Citric acid.'
In citric acid cycle, the step not using dehydrogenase enzymes is
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Malic acid to oxaloacetate.
0%
Succinate to fumarate.
0%
Oxaloacetate to citric acid.
0%
Citric acid to -ketoglutarate.
Explanation
Malic acid converts into oxaloacetate in the presence of Malic dehydrogenase.
Succinate converts into fumarate in the presence of Succinic dehydrogenase.
Oxaloacetic acid forms citric acid in the presence of enzyme citrate synthetase.
Citric acid converts into alpha-ketoglutarate in stepwise reactions.
So the correct option is 'Oxaloacetate to citric acid'.
Substrate level phosphorylation in Krebs cycle occurs during conversion of ________________.
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Succinate to malate
0%
Succinyl CoA to succinate
0%
Malate to Fumarate
0%
Malate to oxaloacetate
0%
Citrate to -Ketoglutarate
In Krebs cycle, second decarboxylation occurs during
Report Question
0%
Pyruvate Acetyl CoA
0%
-Ketoglutarate Succinyl CoA
0%
Oxalosuccinic acid -Ketoglutarate
0%
Malic acid Fumaric acid
Explanation
In Krebs' cycle, decarboxylation occurs twice during the completion of one cycle. Second decarboxylation occurs when ketoglutarate (5) is converted to succinyl CoA
(4 C)
by ketoglutarate dehydrogenase liberating CO2.
So the answer is 'Ketoglutarate Succinyl CoA'.
Oxidative decarboxylation occurs during the reaction
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0%
Citrate Isocitrate
0%
Pyruvic acid Acetyl CoA
0%
Succinate Fumarate
0%
Fumarate Malate
Explanation
Pyruvic acid from glycolysis can only enter Krebs' cycle by going through a link reaction. In this, pyruvic acid is dehydrogenated and decarboxylated by the pyruvate dehydrogenase enzyme, liberating CO2 and H2. H2 reduces NAD to NADH2. The product formed is acetyl CoA. Such a reaction is called oxidative decarboxylation.
So the answer is 'Pyruvic acid Acetyl CoA'.
Select the wrong statement.
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RQ is 0.7 with tripalmitin.
0%
Link compound between glycolysis and Krebs cycle is malic acid.
0%
36 ATP molecules are produced per glucose molecule in aerobic respiration.
0%
2 ATP molecules are produced per glucose molecule in anaerobic respiration.
Explanation
A) RQ is 0.7 with tripalmitin as it consumes more oxygen than carbon dioxide release.
B)
Link compound between glycolysis and Krebs cycle is Acetyl coenzyme A which is formed after the oxidative decarboxylation of pyruvic acid.
C)
36 ATP molecules are produced per glucose molecule in aerobic respiration obtain by glycolysis. oxidative decarboxylation and TCA.
D)
2 ATP molecules are produced per glucose molecule in anaerobic respiration.
So the correct option is '
Link compound between glycolysis and Krebs cycle is malic acid'.
After glycolysis, fate of glucose in mitochondrial matrix is
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0%
Hydrolysis
0%
Oxidative decarboxylation
0%
Reduction
0%
Oxidation
Explanation
After glycolysis, the end product pyruvic acid undergoes Krebs cycle but before that, it has to go through link reaction. The link reaction occurs in mitochondrial matrix and converts pyruvic acid to acetyl CoA through the pyruvate dehydrogenase complex. Such a reaction is called oxidative decarboxylation. Hydrogen and carbon dioxide are released.
So, the correct answer is 'Oxidative decarboxylation'.
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