Bioenergetic MCQs

Set of Important MCQs on BIOLOGICAL OXIDATION AND BIOENERGETICS for the preparation of tests for chemistry and biology. 

Which redox couples reacts directly with oxygen?

  1. Cytochrome C
  2. FADH2
  3. Cytochrome a3
  4. Complex V

Question Answer: Cytochrome a3

How many electrons are used by cytochrome oxidase to reduce to reduce O2 in respiratory chain?

  1. One
  2. Four
  3. Three
  4. Two

Question Answer: Four


When is it proper to write the reaction: A Go= .RT InKeq?

  1. When A G=0
  2. Always
  3. When Keq=1
  4. When all reactants and products are at unimolar concentrations

Question Answer: When A G=0

Transfer of electrons from NADH to molecular oxygen can generate how much (kcal/mol)?

  1. 1.14 kcal/mol
  2. 82.0 Kcal/mol
  3. 21.9 kcal/mol
  4. 52.6 kcal/mol

Question Answer: 52.6 kcal/mol

Which statements regarding mitochondria is true?

  1. Calcium ions can freely diffuse through inner membrane
  2. the inner membrane is folded into cristae to decrease the matrix volume
  3. The matrix is protein-rich gel that, contains the enzymes involved in oxide-tive phosphorylation
  4. Outer membrane is permeable to most of molecules, where inner membrane is impermeable to most.

Question Answer: Outer membrane is permeable to most of molecules, where inner membrane is impermeable to most.

Which is true for Living cells and organisms?

  1. Are closed systems
  2. Exchange energy and material with their surroundings
  3. Exchange energy but not matter with their surroundings
  4. Are at equilibrium with their surroundings

Question Answer: Exchange energy but not matter with their surroundings

Which vitamins is not a component of electron transport chain?

  1. Nicotinamide
  2. Ribolavin
  3. Ubiquinone
  4. Biotin

Question Answer: Biotin

Which redox components has the most negative redox potential (E.)?

  1. NADH
  2. Cytochrome C
  3. EFDH2
  4. Coenzyme Q

Question Answer: NADH

Which gives the maximum (negative) free energy of hydrolysis?

  1. ATP ADP+ Pi
  2. Phosphocreatine
  3. Phosphoenolpyruvate
  4. 1, 3-bisphophoglycerate

Question Answer: Phosphoenolpyruvate

Which one of the following ETC components is not permanently attached to an enzyme or a protein?

  1. Cytochrome oxidase
  2. Cytochrome C
  3. Iron-Sulfur clusters
  4. Ubiquinone

Question Answer: Ubiquinone

A chemical reaction is more likely to occur spontaneously, if

  1. The products of the reaction are more complex than the reactions
  2. The products of the reaction are more disordered then the reactants
  3. The system takes up heat from its surroundings
  4. The system gains free energy

Question Answer: The products of the reaction are more disordered then the reactants

Which carbon-containing molecule is most oxidized?

  1. Carbon dioxide
  2. Methane
  3. Carbon monoxide
  4. ethanol

Question Answer: Carbon dioxide

The free energy change, A G:

  1. Is equal to zero at equilibrium
  2. Is directly proportional to the standard free energy change
  3. can only be calculated when reactants and products are at 1 M concentation
  4. Is equal to -RT in Keq

Question Answer: Is equal to zero at equilibrium

What is the voltage difference between cytosolic and matrix sides of inner mitochondrial membrane during electron transport?

  1. 1.424 V
  2. 0.14 V
  3. 2.3 V
  4. 2.4 V

Question Answer: 0.14 V

Under what conditions of Kea, will the reaction proceed in the forward direction?

  1. If Keg is less than 1
  2. If Keg is 0
  3. If Key is negative
  4. If Keg is greater than 1

Question Answer: If Keg is greater than 1

Which is true regarding ATP and ADP is the intact cells?

  1. Magnesium binds with ADP and ATP
  2. Magnesium binds with ATP only
  3. Manganese binds with ATP only
  4. Manganese binds with ADP and

Question Answer: Magnesium binds with ADP and ATP

Cyanide is a poison because it inhibits respiration by:

  1. Combination with Red Blood cells
  2. Inhibition of Succinate-Q reductase
  3. Inhibition of NADH-Q reductase
  4. Inhibition of cytochrome oxidase

Question Answer: Inhibition of cytochrome oxidase

Electrons form pyruvic acid enter the mitochondrial electron transport chain at:

  1. Co-enzyme Q
  2. NADH-Q reductase
  3. QH2-cytochrome reductase
  4. Cytochrome oxidase

Question Answer: NADH-Q reductase

Electrons can be transferred from one molecule (electron donor) to another molecule (electron acceptor) by all of the following ways, except:

  1. As a proton
  2. Directly as an electron
  3. As a hydrogen atom
  4. As a hydride ion

Question Answer: As a proton

Which metal ions is associated with superoxide dismutase’s?

  1. Zn++
  2. Mn”
  3. Cu
  4. All of these

Question Answer: All of these

Which is true for flavin nucleotides?

  1. They act as prosthetic groups
  2. They always accept two electrons
  3. They are utilized by oxygenases
  4. They have no reduction potential unless bound to a protein.

Question Answer: They act as prosthetic groups

Which complexes contains FMN?

  1. Cytochrome C
  2. FADH2
  3. NADH-Q Reductase
  4. Complex II

Question Answer: NADH-Q Reductase

Which is not the function transport of mitochondrial electron system?

  1. Unidirectional proton pumping out of mitochondria matrix
  2. Production of metabolic water
  3. ATP synthesis from ADP and Pi
  4. Oxidation of reduced NADH and FADH2

Question Answer: ATP synthesis from ADP and Pi

Cytochrome Oxidase is a conjugated protein, it carries Which prosthetic group, in addition to the heme group:

  1. Mn
  2. Co
  3. Mg
  4. Cu

Question Answer: Mn

Which enzymes can catalyze the conversion of AMP to ADP

  1. Creatine kinase
  2. Polyphosphate kinase
  3. Adenylate kinase
  4. Nucleoside diphosphate kinase

Question Answer: Adenylate kinase

The flavoproteins of the electron transport chain are complexed with:

  1. Cytochrome a
  2. Iron sulfur proteins

C Cytochrome C

  1. Cytochrome Q

Question Answer: Iron sulfur proteins

Mitochondrial β-oxidation is the oxidation of which of the following?

  1. Cholesterol
  2. Amino acids
  3. Acetyl CoA
  4. Fatty acids

Question Answer: Fatty acids

More Biochemistry MCQs

  1. Acid and Base MCQs
  2. Carbohydrate MCQs
  3. Proteins MCQs
  4. Lipids and Biomembranes MCQs
  5. Nucleic acids MCQs
  6. Metabolism of Carbohydrates MCQs
  7. Enzymes MCQs
  8. Vitamins and Hormones MCQs
  9. Bioenergetic MCQs
  10. Biotechnology MCQs
  11. Biotechnology MCQs 2
  12. Basic Biochemistry MCQs (important)
  13. CHEMISTRY MCQs From all subjects of  Chemistry
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