CBSE Class 11 Biology Respiration in Plants MCQs Set B

Question: In Krebs’ cycle, the FAD precipitates as electron acceptor during the conversion of
a) fumaric acid to malic acid
b) succinic acid to fumaric acid
c) succinyl CoA to succinic acid
d) α-ketoglutarate to succinyl CoA.

Answer: b

Question: Pyruvate kinase enzyme catalyses
a) first irreversible step of glycolysis
b) second irreversible step of glycolysis
c) third irreversible step of glycolysis
d) fourth irreversible step of glycolysis

Answer: c

Question. Enzymes differ from inorganic catalysts because enzymes get damaged at high temperatures This difference :
a) is applicable to all enzymes
b) is not applicable to thermolabile enzymes
c) is not applicable to the enzymes of thermophilic organisms
d) is applicable to thermostable enzymes

Answer: c

Question: Which of the following is the connecting link between glycolysis and Krebs cycle?
a) Acetyl CoA
b) Oxalosuccinic acid
c) Pyruvic acid
d) Citric acid

Answer: a

Question: Cytochrome is
a) metallo flavo protein
b) Fe containing porphyrin pigment
c) glycoprotein
d) lipid.

Answer: b

Question: By which of the following complex, proton is pumped to reach ATP synthase to participate in ATP synthesis?
a) Cytochrome b6f
b) Cytochrome c oxidase
c) Cytochrome a – a3
d) Cytochrome bc

Answer: a

Question: Which of the following products are obtained by anaerobic respiration from yeast?
a) Beer and wine
b) Alcohols
c) CO₂
d) All of these

Answer: d

Question. Select out the correct sequence of glycolytic steps:
a) PGAL → 3-PGA → 1,3-BiPGA → PEP
b) PGAL → 1,3-BiPGA → PEP → 3-PGA
c) PGAL → 1,3-BiPGA → 3-PGA → PEP
d) PGAL → PEP → 1,3-BiPGA → 2-PGA

Answer: c

Question: In alcohol fermentation
a) triose phosphate is the electron donor while acetaldehyde is the electron acceptor
b) triose phosphate is the electron donor while pyruvic acid is the electron acceptor
c) there is no electron donor
d) oxygen is the electron acceptor.

Answer: a

Question: At the end of glycolysis, six carbon compound ultimately changes into
a) ethyl alcohol
b) acetyl Co-A
c) pyruvic acid
d) ATP.

Answer: c

Question: Which of these statements is incorrect?
a) Enzymes of TCA cycle are present in mitochondrial matrix.
b) Glycolysis occurs in cytosol.
c) Glycolysis operates as long as it is supplied with NAD that can pick up hydrogen atoms.
d) Oxidative phosphorylation takes place in outer mitochondrial membrane.

Answer: d

Question: Connecting link between glycolysis and Krebs’ cycle before pyruvate entering Krebs’ cycle is changed to
a) oxaloacetate
b) PEP
c) pyruvate
d) acetyl CoA.

Answer: d

Question. How much amount of energy present in glucose, get released during lactic acid and alcohol fermentation ?
a) 7 percent
b) less than seven percent
c) more than seven percent
d) always 2 percent

Answer: b

Question: When yeast ferments glucose, the products obtained are
a) ethanol and CO₂
b) methanol and CO₂
c) ethanol and water
d) water and CO₂.

Answer: a

Question: The energy-releasing metabolic process in which substrate is oxidised without an external electron acceptor is called
a) glycolysis
b) fermentation
c) aerobic respiration
d) photorespiration.

Answer: b

Question: Oxidative phosphorylation is
a) formation of ATP by transfer of phosphate group from a substrate to ADP
b) oxidation of phosphate group in ATP
c) addition of phosphate group to ATP
d) formation of ATP by energy released from electrons removed during substrate oxidation.

Answer: d

Question: In mitochondria, protons accumulate in the
a) outer membrane
b) inner membrane
c) intermembrane space
d) matrix.

Answer: c

Question. What is the significance of respiration ?
a) Production of cellular energy currency
b) Provides carbon skeleton as precursor for synthesis of various chemicals
c) loss of weight
d) Both a) and b)

Answer: d

Question: Which of the following is the key intermediate compound linking glycolysis to the Krebs’ cycle?
a) Malic acid
b) Acetyl CoA
c) NADH
d) ATP

Answer: b

Question: Where is respiratory electron transport system (ETS) located in plants ?
a) Mitochondrial matrix
b) Outer mitochondrial membrane
c) Inner mitochondrial membrane
d) Intermembrane space

Answer: c

Question: Oxidative phosphorylation is production of
a) ATP in photosynthesis
b) NADPH in photosynthesis
c) ATP in respiration
d) NADH in respiration.

Answer: c

Question. In aerobic respiration, the ultimate or final electron acceptor is :
a) Atomic oxygen
b) Molecular oxygen
c) Cytochrome a3
d) Water

Answer: b

Question: Which statement is wrong for Krebs’ cycle?
a) There is one point in the cycle where FAD+ is reduced to FADH2.
b) During conversion of succinyl CoA to succinic acid, a molecule of GTP is synthesised.
c) The cycle starts with condensation of acetyl group (acetyl CoA) with pyruvic acid to yield citric acid.
d) There are three points in the cycle where NAD+is reduced to NADH + H+.

Answer: c

Question: Cytochromes are found in
a) cristae of mitochondria
b) lysosomes
c) matrix of mitochondria
d) outer wall of mitochondria.

Answer: a

Question. The complete oxidation of one molecule of pyruvate by the stepwise removal of all the hydrogen atoms:
a) leaving six molecules of CO2
b) leaving two molecules of CO2
c) leaving four molecules of CO2
d) leaving three molecules of CO2

Answer: d

 Question: An enzymes of TCA cycle are located in themitochondrial matrix except one which is located in inner mitochondrial membrane in eukaryotes and in cytosol in prokaryotes. This enzyme is
a) Succinate dehydrogenase
b) Lactate dehydrogenase
c) Isocitrate dehydrogenase
d) Malate dehydrogenase

Answer: a

Question: In glycolysis, during oxidation electrons are removed by
a) ATP
b) glyceraldehyde-3-phosphate
c) NAD+
d) molecular oxygen.

Answer: c

Question: The first phase in the breakdown of glucose, in animal cell, is
a) fermentation
b) Krebs’ cycle
c) glycolysis
d) ETS.

Answer: c

Question. Enzyme, which catalyzes the breakdown of hydrogen peroxide to water and oxygen, has which type of cofactor?
a) Tightly bound inorganic compound
b) Tightly bound organic compound
c) Permanently bound inorganic compound
d) Loosely bound organic compound

Answer: b

Question: Conversion of glucose to glucose-6-phosphate, the first irreversible reaction of glycolysis, is catalysed by
a) phosphofructokinase
b) aldolase
c) hexokinase
d) enolase.

Answer: c

Question: The number of substrate level phosphorylations in one turn of citric acid cycle is
a) zero
b) one
c) two
d) three.

Answer: b

Question: In which one of the following do the two names refer to one and the same thing ?
a) Krebs’ cycle and Calvin cycle
b) Tricarboxylic acid cycle and citric acid cycle
c) Citric acid cycle and Calvin cycle
d) Tricarboxylic acid cycle and urea cycle

Answer: b

Question. TCA cycle starts with condensation of acetyl group with :
a) OAA
b) Water
c) NAD
d) both a) and b)

Answer: d

Question: Which one of the following statements about cytochrome P450 is wrong?
a) It is a coloured cell.
b) It is an enzyme involved in oxidation reactions.
c) It has an important role in metabolism.
d) It contains iron.

Answer: a

Question: Anaerobic respiration, after glycolysis is also called as
a) fermentation
b) fragmentation
c) restoration
d) multiplication

Answer: a

Question: The correct sequence of electron acceptor in ATP synthesis is
a) Cyt. b, c, a3, a
b) Cyt. c, b, a, a3
c) Cyt. a, a, b, c
d) Cyt. b, c, a, a3.

Answer: d

Question: What is the role of NAD+ in cellular respiration?
a) It functions as an enzyme.
b) It functions as an electron carrier.
c) It is a nucleotide source for ATP synthesis.
d) It is the final electron acceptor for anaerobic respiration.

Answer: b,c

Question. During respiration of Yeast which of the following enzyme is not used in oxygen stressed conditions ?
a) Enolase
b) Pyruvic acid decarboxylase
c) Alcohol dehydrogenase
d) Aconitase

Answer: d

Question: End product of glycolysis is
a) acetyl CoA
b) pyruvic acid
c) glucose 1-phosphate
d) fructose 1-phosphate.

Answer: b

Question: The 1992 Nobel Prize for medicine was awarded to Edmond H. Fischer and Edwin J. Krebs for their work concerning
a) reversible protein phosphorylation as a biological regulation mechanism
b) isolation of the gene for a human disease
c) human genome project
d) drug designing involving inhibition of DNA synthesis of the pathogen.

Answer: a

Question: In alcoholic fermentation, NAD+ is produced during the
a) reduction of acetyldehyde to ethanol.
b) oxidation of glucose.
c) oxidation of pyruvate to acetyl coA.
d) hydrolysis of ATP to ADP

Answer: a

Question: All enzymes of TCA cycle are located in the mitochondrial matrix except one which is located in inner mitochondrial membranes in eukaryotes and in cytosol in prokaryotes. This enzyme is
a) isocitrate dehydrogenase
b) malate dehydrogenase
c) succinate dehydrogenase
d) lactate dehydrogenase.

Answer: c

Question: End products of aerobic respiration are
a) sugar and oxygen
b) water and energy
c) carbon dioxide, water and energy
d) carbon dioxide and energy.

Answer: c

Question: Terminal cytochrome of respiratory chain which donates electrons to oxygen is
a) Cyt b
b) Cyt c
c) Cyt a1
d) Cyt a3.

Answer: d

Question: In which one of the following processes CO2 is not released?
a) Aerobic respiration in plants
b) Aerobic respiration in animals
c) Alcoholic fermentation
d) Lactate fermentation

Answer: d

Question: Glycolysis occurs in
a) mitochondria
b) chloroplast
c) cytoplasm
d) peroxisome

Answer: c

Question: Which of the metabolites is common to respiration mediated breakdown of fats, carbohydrates and proteins?
a) Fructose 1, 6 – bisphosphate
b) Pyruvic acid
c) Acetyl CoA
d) Glucose – 6 – phosphate

Answer: c

Question: End product of citric acid cycle/Krebs’ cycle is
a) citric acid
b) lactic acid
c) pyruvic acid
d) CO₂ + H₂O.

Answer: d

Question: In glycolysis, glucose molecule is converted into
a) PEP
b) RuBP
c) acetyl CoA
d) pyruvic acid

Answer: d