Tag: oxidative phosphorylation

Questions Related to oxidative phosphorylation

Choose the correct answers from the alternatives given :
Chemiosmotic phosphorylation is dependent upon

  1. the ability of ADP? to join with P even in the absence of a supply of energy

  2. the establishment of an electrochemical hydrogen ion $(H^+)$ gradient

  3. an outside supply of phosphate and other chemicals

  4. the diffusion of waste across a differentially permeable membrane


Correct Option: B
Explanation:

  • Chemiosmotic phosphorylation is the process where ATP is formed by the ATP synthase complex which is present in the inner membrane of the mitochondria.
  • The formation of ATP by this complex takes place when 2 hydronium ions are transported across the complex from the inter membrane space down its concentration gradient.
  • Thus the formation of ATP in this process takes place due to the concentration gradient that is formed by the presence of hydronium ion that is formed by the ETS Chain when the electron along with hydronium ions are transported from the NADH and FADH.
  • Therefore the answer 'the establishment of an electrochemical hydrogen ion (H+) gradient' is correct.










Choose the correct answers from the alternatives given :
Substrate-level phosphorylation takes place in 

  1. Krebs cycle and the transition reaction

  2. glycolysis and the electron transport system

  3. electron transport system and the transition reaction

  4. glycolysis and the Krebs cycle


Correct Option: D
Explanation:
  • Substrate level phosphorylation is the reaction where ATP is formed by the phosphate molecule that is taken from the substrate in the reaction.
  • In glycolysis during the conversion of 1,3 bisphosphoglyceric acid to 3 phosphoglyceric acid and coversion of phosphophenol to pyruvic acid; one molecule of ATP is formed during each reaction.
  • In kerb cycle during the formation of succinic acid from succinyl CoA GTP is formed which is a substrate level phosphorylation, afterwards this GTP is converted to ATP in a coupled reaction.
  • No substrate level phosphorylation takes place in oxidative phosphorylation or ETS
  • Therefore the answer 'glycolysis and the Krebs cycle' is correct.

Choose the correct answers from the alternatives given :
Which of the following occurs only in aerobic conditions?

  1. Glycolysis

  2. Lactate respiration

  3. Oxidative phosphorylation

  4. Fermentation


Correct Option: C
Explanation:

  • Glycolysis is the first part of the reaction that provides substrate for the further reaction of aerobic and anaerobic reaction. IT takes place in cytoplasm and does not require any oxygen.
  • LActate respiration and fermentation both are the reaction that take place in the cells or the tissues which respiration in anaerobic conditions or when there is not enough oxygen.
  • Oxidative phosphorylation is the process that takes place in the in the inner mitochondrial membrane where the electrons and hydronium ions are transported through a series of complexs and at the end the electrons and hydronium are accepted by the oxygen and water is formed, this is the process in the aerobic respiration where the oxygen is used and it cannot be completed with it.
  • Therefore the answer option 'Oxidative phosphorylation' is correct.







Choose the correct answers from the alternatives given :
The direct energy source that drives ATP synthesis during oxidative phosphorylation is 

  1. a difference of $^H+$ concentration on opposite sides of the inner mitochondrial membrane

  2. the affinity of oxygen for electrons

  3. oxidation of glucose and other organic compounds

  4. endergonic flow of electrons down the electron transport chain


Correct Option: A
Explanation:

  • In mitochondria the ETS is used for the transport of electrons and hydronium ions from inner mitochondrial membrane to the inter membrane matrix of mitochondria.
  • Due to this the concentration of hydronium ions increases in the intermembrane matrix.
  • The ATP synthase complex which is present in the inner membrane of the mitochrondria are used for the synthesis of ATP.
  • The complex is used to transport hydronium ions from the intermembrane matrix down its concentration gradient
  • For every 2 hydronium ions transported through the complex one molecule of ATP is generated.
  • Therefore the transport of the H+ ions due the difference in the concentration provides direct energy for the formation of ATP.
  • Therefore the correct answer is option 'a difference of H+ concentration on opposite sides of the inner mitochondrial membrane'.









Choose the correct answers from the alternatives given :
The final electron acceptor of the electron transport chain that functions in oxidative phosphorylation 

  1. pyruvic acid

  2. oxygen

  3. water

  4. $NAD^+$


Correct Option: B
Explanation:

  • Electrons that are transported through the ETS are passed through various complexs of the transport chain such as complex I, cytochrome c cytochrome b, etc
  • When the electrons are passed through the complexs one after the other hydrogen ions are also passed through along with it.
  • After the electrons and the hydrogen have passed through the last of the complex the last acceptor of the electron in this chain will be a molecule of oxygen after reacting to which a molecule of water is formed.
  • Therefore the correct answer is option 'oxygen'.








Choose the correct answers from the alternatives given :
Most of the ATP made during cellular respiration is generated by 

  1. direct synthesis of ATP by the Krebs cycle

  2. substrate-level phosphorylation

  3. oxidative phosphorylation

  4. glycolysis


Correct Option: C
Explanation:
  • Oxidation phosphorylation is the process where the electron acceptor such as NADH and FADH release their H ions and the ions and the electrons are tranported through various complexs of electron transport system.
  • NADH gives electrons which pass through 5 complexs of the ETS and FADH pass through 4 complexs of the ETS 
  • These electron at the end of the transport system react with oxygen and form a molecule of water.
  • Where the proton which is released by the complexs of the ETS during the transport of electrons are used in formation of ATP.
  • one molecule of NADH forms 3 molecules of ATP and one molecule of FADH forms 2 molecules of ATP
  • So after one cycle of kerb 4 molecules of NADH are released and one molecule of FADH which results in formation of 12 ATP and 2 ATP respectively. Thus generating 14 ATP for each pyruvic acid.
  • Therefore the amount of the maximum generated ATP in cellular respiration is done by oxidative phosphorylation.
  • Therefore the answer option 'oxidative phosphorylation' is correct.
All of the following processes can release ${CO} _{2}$ except
  1. Alcoholic fermentation

  2. Oxidative decarboxylation and Krebs' cycle

  3. Oxidative phosphorylation

  4. Conversion of $\alpha$-ketoglutaric acid to succinic acid


Correct Option: C
Explanation:

The process of oxidative phosphorylation involves the production of ATP by utilizing electrons falling from the hydrogen in glucose to the oxygen in a living cell. It does not lead to the production of carbon dioxide molecules.

Thus, the correct answer is 'Oxidative phosphorylation.'

Read the given statements and select the correct option.
Statement 1: During photophosphorylation (of photosynthesis), light energy is utilised for the production of a proton gradient during ATP synthesis.
Statement 2: In respiration, the energy of oxidation-reduction is utilised for the phosphorylation and thus the process is called oxidative phosphorylation.
  1. Both statements 1 and 2 are correct.

  2. Statement 1 is correct but statement 2 is incorrect.

  3. Statement 1 is incorrect but statement 2 is correct.

  4. Both statements 1 and 2 are incorrect.


Correct Option: A
Explanation:

Photophosphorylation occurs in the grana and requires the direct sunlight energy to make energy-carrier molecules that are used in the dark reaction. The light energy is trapped by chlorophyll to make ATP and NADPH. Oxidative phosphorylation is the synthesis of energy-rich ATP molecules with the help of energy liberated during oxidation of reduced co-enzymes (NADH,${FADH} _{2}$) produced in respiration.

So the correct answer is 'Both statements 1 and 2 are correct'.

Which one is not correct for oxidation of food?

  1. It is multiple process

  2. All released energy is traped in form of ATP

  3. Traped energy is further used for bio synthesis of other molecules

  4. Oxidisable compound is known as respiratory substrate


Correct Option: B
Explanation:

During the oxidation of carbon atoms from complex organic food molecule, carbon dioxide is released as a waste product. The energy released from these reactions is not used up by the cells completely. Alternatively, it is converted into ATP and NADH, and this can be used throughout the cell to power metabolism and construct new cellular components. In addition, workhorse proteins called enzymes use this chemical energy to catalyze chemical reactions within the cell.

So, the correct option is 'All released energy is trapped in form of ATP'.

During oxidative phosphorylation, proton return to

  1. Matrix from outside

  2. Outside from matrix

  3. In both directiion

  4. Mitochondria to cytoplasm


Correct Option: A
Explanation:

Oxidative phosphorylation is the process of formation of ATP (energy) molecules inside the plant and animal cells. It takes place inside the mitochondria. During the oxidative phosphorylation, electrons flow from NADH  or FADH to Othrough the four different type complexes found in the inner mitochondrial membrane, which leads the pumping of the proton from outside to the matrix.

So, the correct answer is ' Matrix from outside '