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12th Grade > Biology

RESPIRATION IN PLANTS MCQs

Total Questions : 62 | Page 1 of 7 pages
Question 1. Enzymes located in mitochondrial membrane are ______.
  1.    Enolase and Catalase
  2.    Flavoproteins and Cytochromes
  3.    Hexokinase and Zymase
  4.    Citrate synthetase and Glutamate dehydrogenase
 Discuss Question
Answer: Option B. -> Flavoproteins and Cytochromes
:
B
Flavoproteins & cytochromes are enzymes of the ETC complexes, these complexes are found in the inner mitochondrial membrane.
Enolase and hexokinase are glycolytic enzymes and are therefore found in the cytoplasm, whereas catalase is an enzyme that breaks down hydrogen peroxide and is found in an organelle called peroxisome. Zymase is an enzyme involved in alcohol fermentation. Citrate synthetase is an enzyme of the Kreb's cycle and is found in the mitochondrial matrix.
Question 2. The chemiosmotic coupling hypothesis of oxidative phosphorylation proposes that adenosine triophosphate (ATP) is formed because _______.
  1.    High energy bonds are formed in mitochondrial proteins
  2.    ADP is pumped out of the matrix into the intermembrane space
  3.    A proton gradient forms across the inner membrane
  4.    There is a change in the permeability of the inner mitochondrial membrane towards adenosine diphosphate (ADP)
 Discuss Question
Answer: Option C. -> A proton gradient forms across the inner membrane
:
C
As per chemiosmotic hypothesis ATP synthetase becomes active in ATP formation only where there is a protein gradient having a higher concentration of H+ or protons on the inner side as composed to the outer side
Question 3. Pyruvate dehydrogenase is the enzyme that converts __________.
  1.    Glucose to pyruvate
  2.    Pyruvic acid into lactic acid
  3.    Pyruvate to acetyl CoA
  4.    Pyruvate to glucose
 Discuss Question
Answer: Option C. -> Pyruvate to acetyl CoA
:
C
Pyruvatepyruvatedehydrogenase−−−−−−−−−−−−−AcetylCoA
Pyruvate dehydrogenase is the enzyme that catalyzes the oxidation of pyruvate, by decarboxylating it to release carbon dioxide and it adds a coenzyme molecule to synthesize acetyl-CoA.
Question 4. The R.Q. is infinity, when  ______
  1.    Carbohydrate is respired aerobically
  2.    Fat is respired aerobically
  3.    Protein is respired aerobically
  4.    Carbohydrate is respired anaerobically
 Discuss Question
Answer: Option D. -> Carbohydrate is respired anaerobically
:
D
Respiratory quotient is the ratio of the volume of carbon dioxide evolved to that of oxygen consumed by an organism, tissue, or cell in a given time.
That is, R.Q. = Volume ofCO2evolved/ Volume ofO2consumed
Since noO2is consumed in anaerobic respiration, R.Q. = Volume ofCO2evolved/0 =
Question 5. Cell respiration is carried out by ________.
  1.    Ribosome
  2.    Mitochondria
  3.    Chloroplast
  4.    Golgi bodies
 Discuss Question
Answer: Option B. -> Mitochondria
:
B
In 1950, Kolliker for the first time saw mitochondria. Later on C Benda coined the term mitochondria. These are the sites of cellular respiration, oxidative phosphorylation, synthesis of heame protein, cytochrome, myoglobin, etc.
Question 6. The proper sequence of stages in glycolysis is
  1.    Glucose priming, cleavage and rearrangement, oxidation, ATP generation
  2.    Cleavage and rearrangement, glucose priming, ATP generation, oxidation
  3.    Glucose priming, oxidation, cleavage and rearrangement, ATP generation
  4.    ATP generation, oxidation, glucose priming, cleavage and rearrangement
 Discuss Question
Answer: Option A. -> Glucose priming, cleavage and rearrangement, oxidation, ATP generation
:
A
Glycolysis is a ten step process. In the first few steps glucose is primed. It is converted to glucose-6-phosphate, which is trapped in the cell and can not leave the cell due to its negative charge. It is then broken down and rearranged to form two high energy 3C molecules of glyceraldehyde-3-phosphate. Glyceraldehyde-3-phosphate then undergoes oxidation to form 1,3-bisphophoglycerate, creating a high energy NADH molecule. The last aspect of glycolysis is the harvest phase, where the ATPs invested in the priming are returned and 2 more is generated as a pay off.
Question 7. ________ process fuelled by the ETC, drives the synthesis of ATP. 
  1.    Chemiosmosis
  2.    Phosphorylation
  3.    Glycolysis
  4.    Fermentation
 Discuss Question
Answer: Option A. -> Chemiosmosis
:
A
Chemiosmosis is the diffusion of ions across a selectively permeable membrane. In the electron transport chain, the energy stored in the high energy electron carriers are transferred to oxygen, and used to create a protongradient, across the inner mitochondrial membrane. This proton gradient drives chemiosmosis and drives the generation of ATP by the movement of hydrogen ions through the ATP synthase complex.
ATP synthase is the enzyme that makes ATP by chemiosmosis. The generation of ATP by chemiosmosis occurs in the chloroplasts and mitochondria as well as in some bacteria.
Question 8. Assertion: Yeasts, such as Saccharomyces Cerivisiae are used in baking industry.
Reason: Carbon dioxide produced during fermentation causes bread dough to rise by thermal expansion.
  1.    Both assertion and reason are true and reason is the correct explanation for assertion
  2.    Both reason and assertion are true but reason is not correct explanation for assertion
  3.    Assertion is true but reason is false
  4.    Assertion is true but reason is false
 Discuss Question
Answer: Option A. -> Both assertion and reason are true and reason is the correct explanation for assertion
:
A
Baker’s yeast (Saccharomyces Cerivisiae) is added to flour during kneading. Yeast secreted enzymes like amylase (changes some starch to maltase), maltose (maltose to glucose) and zymase (glucose to ethyl alcohol and carbon dioxide). The dough swells up or leavens. Leavened dough is baked and both alcohol and carbon dioxide evaporate. The bread becomes soft and porous.
Question 9. The mechanism of ATP formation both in chloroplast and mitochondria is explained by ______.
  1.    Relay pump theory of Godlewski
  2.    Munch’s pressure/mass flow model
  3.    Chemiosmotic theory of Mitchell
  4.    Cholondy – Went’s model
 Discuss Question
Answer: Option C. -> Chemiosmotic theory of Mitchell
:
C
As per Peter Mitchell’s chemiosmotic – coupling hypothesis, outward pumping of protons across the inner chloroplast or mitochondrial membrane results in accumulation of protons between outer and inner membrane. A proton gradient is thus established. As protons now flow back passively down the gradient, the proton motive force is utilized to synthesize ATP.
Question 10. All enzymes of TCA cycle are located in the mitochondrial matrix except one, which is located in the inner mitochondrial membranes in eukaryotes and cytosol in prokaryotes. This enzyme is ______.
  1.    Lactate dehyrogenase
  2.    Isocitrate dehydrogenase
  3.    Malate dehydrogenase
  4.    Succinate dehydrogenase
 Discuss Question
Answer: Option D. -> Succinate dehydrogenase
:
D
Succinate dehydrogenase enzyme is present on inner membrane of mitochondria and is a part of the complex II in the ETC. It catalyses the oxidation of succinate to fumarate in the Kreb's cycle and channels the FADH2 produced during this reaction into the ETC.

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