Tag: bio-chemistry

Questions Related to bio-chemistry

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

bio-chemistry biological oxidation oxidative phosphorylation living organisms and energy production glycolysis

  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

Show answer
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 

bio-chemistry biological oxidation oxidative phosphorylation living organisms and energy production glycolysis

  1. pyruvic acid

  2. oxygen

  3. water

  4. $NAD^+$

Show answer
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 

bio-chemistry biological oxidation oxidative phosphorylation living organisms and energy production glycolysis

  1. direct synthesis of ATP by the Krebs cycle

  2. substrate-level phosphorylation

  3. oxidative phosphorylation

  4. glycolysis

Show answer
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
bio-chemistry biological oxidation oxidative phosphorylation living organisms and energy production glycolysis

  1. Alcoholic fermentation

  2. Oxidative decarboxylation and Krebs' cycle

  3. Oxidative phosphorylation

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

Show answer
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.
bio-chemistry biological oxidation oxidative phosphorylation living organisms and energy production glycolysis

  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.

Show answer
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?

bio-chemistry biological oxidation oxidative phosphorylation living organisms and energy production glycolysis

  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

Show answer
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

bio-chemistry biological oxidation oxidative phosphorylation living organisms and energy production glycolysis

  1. Matrix from outside

  2. Outside from matrix

  3. In both directiion

  4. Mitochondria to cytoplasm

Show answer
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 O2 through 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 '

During cyclic photophosphorylation proton gradient established by

bio-chemistry biological oxidation oxidative phosphorylation living organisms and energy production glycolysis

  1. $PQ$ mediated $H^+$ transfer

  2. Photolysis of $H _2O$

  3. $NADP$ reductase mediated withdrawal of $H^+$

  4. All of the above

Show answer
Correct Option: A
Explanation:

The proton gradient produced by proton pumping during the electron transport chain is used to synthesize ATP. Protons flow down their concentration gradient into the matrix through the membrane protein ATP synthase, causing it to spin & catalyze the conversion of ADP to ATP.

So, the correct option is 'PQ mediated H+ transfer'.

Correct answer(w.r.t. ETS and oxidative phosphorylation in mitochondria):
(i) $F _1$ headpiece is a peripheral membrane complex and contains site of ATP synthesis
(ii) Passage of electrons through channel is coupled to catalytic site of $F _0$ component for ATP production.
(iii) $F _0$ is integral membrane protein  complex that forms the channel through which protons cross inner membrane
(iv) Cyt c is small protein attached to inner surface of inner mitochondrial membrane.
*

bio-chemistry biological oxidation oxidative phosphorylation living organisms and energy production glycolysis

  1. (i) and (iii) are correct

  2. (ii) and (iii) are incorrect

  3. (iii) and (iv) are correct

  4. (i) and (i)v are incorrect

Show answer
Correct Option: A

In case NADH is oxidised in a single step to form water.

bio-chemistry biological oxidation oxidative phosphorylation living organisms and energy production glycolysis

  1. Cell will burn

  2. Most of energy is liberated as heat

  3. $3$ ATP are formed

  4. $5$ ATP are formed

Show answer
Correct Option: B
Explanation:

NADH is reoxidized in a single step to form water (in the presence of oxygen). NADH to donate electrons directly to Oxygen to water. NADH to Oxygen the many-electron carriers in the electron transport chain and heat is liberated as most of the energy.

So the correct answer is 'Most of the energy is liberated as heat'.