This set of Botany Assessment Questions focuses on “Aerobic Respiration – 2”.
1. How many points are there in the TCA cycle where NAD+ is reduced?
Explanation: There are three points in the TCA cycle where NAD+ is reduced to NADH + H+ and one point where FAD+ is reduced to FADH2. In a coupled reaction GTP is converted to GDP with the simultaneous synthesis of ATP from ADP.
2. Which of the following points are not necessary for the TCA to run continuously?
a) Replenishment of Oxaloacetic acid
b) Regeneration of NAD+
c) Regeneration of FAD+
d) Regeneration of malic acid
Explanation: The points which are necessary for the TCA cycle to run continuously are:
i. Continued replenishment of Oxaloacetic acid
ii. Regeneration of NAD+ from NADH
iii. Regeneration of FAD+ from FADH2
3. What is the full form of ETS?
a) Electrolyte Transport Serum
b) Electrolyte Tissue System
c) Electron Transport System
d) Electron Transmission System
Explanation: ETS stands for Electron Transport System. It is the metabolic pathway where the products of glycolysis and Kreb’s cycle are phosphorylated to form ATP.
4. What is the use of ETS?
a) To release and utilise energy
b) To store energy
c) To transfer energy to the surroundings
d) To take energy from the surroundings
Explanation: The steps in the respiratory process in the ETS are to release and utilise the energy stored in NADH + H+ and FADH2. This system is present in the inner mitochondrial membrane.
5. Where are the electrons passed in ETS?
Explanation: In ETS, NADH and FADH2 are oxidise through various steps and the electrons from this process are passed on to Oxygen resulting in the formation of water.
6. Which complex oxidises the electrons produced by NADH?
a) Complex I
b) Complex II
c) Complex V
d) Complex IV
Explanation: Complex I oxidises the electrons produced by NADH. Complex I is also known as NADH dehydrogenase. The electrons from the oxidation of NADH to NAD+ are passed onto the FMN complex which is located in the inner mitochondrial membrane.
7. Ubiquinone receives electrons from Complex I and Complex IV.
Explanation: Ubiquinone receives electrons from Complex I which is NADH dehydrogenase. It also receives reducing equivalents via Complex II which is FADH2 that is generated during the oxidation of succinate in the citric acid cycle.
8. What is reduced Ubiquinone called as?
Explanation: The reduced ubiquinone which is also known as Ubiquinol is oxidised with the transfer of electrons to cytochrome c via cytochrome bc1 complex or Complex III.
9. Cytochrome c acts a carrier between which of the two complexes?
a) Complex I and Complex II
b) Complex II and Complex III
c) Complex III and Complex IV
d) Complex IV and Complex V
Explanation: Cytochrome c is a small protein that is attached to the outer surface of the inner membrane and acts as a mobile carrier for transfer of electrons between Complex III and Complex IV.
10. How many copper centres are present in Complex IV?
Explanation: Complex IV refers to cytochrome c oxidase complex containing cytochromes a and a3, and two copper centres. The electrons in ETS pass from one carrier to another via complex I to IV.
11. Complex IV is responsible for the production of ATP.
Explanation: When the electrons pass from one carrier to another via complex I to IV in the electron transport chain, they are coupled to ATP synthase or Complex V for the production of ATP from ADP and inorganic phosphate.
12. The number of ATP molecules synthesised depends upon which of the following?
a) Nature of electron donor
b) Nature of electron acceptor
c) Nature of proton donor
d) Nature of atom
Explanation: The number of ATP molecules synthesised depends on the nature of the electron donor. Oxidation of one molecule of NADH gives rise to three molecules of ATP, while that of one molecule of FADH2 produces two molecules of ATP.
13. Which of the following is the final hydrogen acceptor?
Explanation: Oxygen acts as the final hydrogen acceptor. Oxygen is present in the matrix of the mitochondria and finally accepts the protons and forms water molecules. Oxygen is the molecule which drives the whole process of oxidative phosphorylation.
14. Which of the following energy is utilised for the production of the proton gradient in ETS?
a) Energy of Oxygen
b) Energy of Hydrogen
c) Energy of Phosphorous
d) Energy of Oxidation-Reduction
Explanation: Unlike photophosphorylation, where it is the light energy that is utilised for the production of proton gradient required for phosphorylation, in respiration, it is the energy of the oxidation-reduction utilised for the same process. It is for this reason that the process is called Oxidative phosphorylation.
15. Which of the following complexes in ETS are involved in the transport of protons?
a) Complex I
b) Complex II
c) Complex V
d) Complex IV
Explanation: In the electron transport system, Complex I, II, III and IV are related to the transport of only electrons in the mitochondria. Complex V is the only complex in ETS which is involved in proton transport.
Sanfoundry Global Education & Learning Series – Biology – Class 11.
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