Tag: bio-chemistry

Questions Related to bio-chemistry

NADH is oxidised to $NAD^+$ in

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

  1. Aerobic respiration

  2. EMP pathway

  3. Fermentation

  4. None of these

Show answer
Correct Option: A,C

If ATP was unavailable to the cell, as would be the case when treated with an uncoupler of oxidative phosphorylation, the effects would be numerous. Among them, $Na^+/K^+$ ATPase function would be inhibited.
What would be a consequence of such an inhibitory action?

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

  1. Inhibiting the $Na^+/K^+$ pump would cause a cessation of all ion movement.

  2. Sodium would leak into the cell and potassium would leak out of the cell, down their electrochemical gradient.

  3. The ion concentration in the cell would "drift" towards that of the intercellular fluid.

  4. Water would flow out of the cell leading to crenation.

Show answer
Correct Option: B
Explanation:

Na$^+$/K$^+$ ATPase, is a cationic pump that transports 3Na$^+$ ions to the outside, while importing 2K$^+$ against their concentration gradient. This maintains the inner membrane potential negative, In inhibition of the pump, the ions will move along their concentration gradient, reaching towards equilibrium through the leak channels that allow passive movement of these ions.

So, the correct answer is 'Sodium would leak into the cell and potassium would leak out of the cell, down their electrochemical gradient'

The function of ATP synthase enzyme is that

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

  1. It uses energy to move ions against their concentration gradient by removing a phosphate group from ATP.

  2. It uses the power of ions moving against their concentration gradient to add a phosphate group to ADP.

  3. It uses the power of ions moving down their concentration gradient to add a phosphate group to ADP.

  4. It uses the power of ions moving against their concentration gradient to remove a phosphate group from ATP.

  5. It uses the power of ions moving down their concentration gradient to remove a phosphate group from ATP.

Show answer
Correct Option: C
Explanation:

Electron transport chain includes the downhill flow of electrons to final electron acceptor through a chain of membrane-bound carriers to facilitate the uphill transport of protons across a proton-impermeable membrane. It produces proton gradient that drives transport of protons (ions) down the concentration gradient through Fo particles of ATP synthase. The proton-motive force that drives movement of protons (ions) provides the energy for ADP phosphorylation. Thus, the correct answer is option C.

NAD of Krebs cycle functions as

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

  1. Acceptor of hydrogen ion and electrons

  2. Oxygen acceptor

  3. Oxygen donor

  4. Donor of phosphate ions

Show answer
Correct Option: A
Explanation:

NAD is a coenzyme which acts as an electron acceptor in Krebs cycle and acquires hydrogen ions to become NADH.

So the correct option is 'Acceptor of hydrogen ion and electrons'.

Oxidative phosphorylation occurs during 

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

  1. Transpiration

  2. Respiration

  3. Protein synthesis

  4. Nitrogen metabolism

Show answer
Correct Option: B
Explanation:

Oxydative phosphorylation is the process of formation of ATP as a result of transfer of electrons from NADH or FADH$ _2$ to O$ _2$. This process which takes place in mitochondria and ATP is the major source of cellular respiration.

So, the correct option is 'Respiration'. 

Enzymes of oxidative phosphorylation occur in

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

  1. Endoplasmic reticulum

  2. Chloroplasts

  3. Mitochondria

  4. Golgi apparatus

Show answer
Correct Option: C
Explanation:

Enzymes that catalyze oxidative phosphorylation are present in the inner membrane which is much less permeable of mitochondria. Oxidative phosphorylation is the process of electrons are transferred from electron donors to electron acceptors 

So the correct option is 'Mitochondria'.

Which is end product of oxidative phosphorylation?

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

  1. ATP

  2. ATP + $H _2O$

  3. NADH

  4. Oxygen.

Show answer
Correct Option: B
Explanation:

the process produces the 2 pyruvate molecule with 2 water molecule, 2 ATP, 2 NADH molecules, and 2 hydrogen ions. At the end of electron transport, oxygen is the final electron acceptor, and it combines also with hydrogen ions to form H2O. The end product of oxidative phosphorylation would be ATP molecules, which carry energy.

So the correct option is 'ATP + H$ _2$O'.

FAD is electron acceptor during oxidation of 

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

  1. Ketoglutarate Succinyl CoA.

  2. Succinic acid Fumaric acid.

  3. Succinyl CoA Succinic acid.

  4. Fumaric acid Malic acid.

Show answer
Correct Option: B
Explanation:

The hydrogen acceptor is FAD during the oxidation of Succinic acid Fumaric acid by succinate dehydrogenase.

So the correct option is 'Succinic acid Fumaric acid.'

Differences between photophosphorylation (PP) and oxidative phosphorylation (OP) is 

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

  1. In PP, synthesis is of ATP while in OP it is of ADP.

  2. In PP, oxygen is evolved while in OP oxygen is taken up.

  3. Both cannot take place in light.

  4. PP can take place in green leaves while OP cannot occur in green leaves.

Show answer
Correct Option: B
Explanation:

Both the oxidative phosphorylation and photophosphorylation are in which cells make energy in the form of ATP, oxidative phosphorylation occurs during cell respiration and photophosphorylation occurs during photosynthesis. Oxygen is released during photophosphorylation and oxygen is taken up.

So the correct option s 'In PP, oxygen is evolved while in OP oxygen is taken up'.

Which one is the last electron acceptor over ETC in oxidative phosphorylation?

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

  1. $H _2$

  2. $Cyt a _3$

  3. Cyt b

  4. $CO _2$

Show answer
Correct Option: B
Explanation:

Iron and copper are present in cytochrome a$ _3$, Iron transfer electron to oxygen through copper, so cytochromea3 called terminal electron donor.

So the correct option is Cyta$ _3$.'