Assertion: Chemiosmosis requires a membrane, a proton pump, a proton gradient and $A T P$ ase.

Reason: The proton gradient is broken down due to movement of proton across the membrane to the lumen through the transmembrane channel of the $F_{0}$ of the $A T P$ ase.

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Solution

Assertion-Reason relation

Chemiosmosis is the ion movement across a semipermeable membrane down the electrochemical gradient. This phenomena leads to the synthesis of $A T P$ during photosynthesis.

The light energy excites the chlorophyll molecules to release electrons which travel through the electron transport chain.

Assertion-Reason relation

The transport of electrons via electron transport chain causes the pumping of protons from the stroma into the lumen of the thylakoid.

This creates a proton gradient across the membrane. The accumulated protons in the lumen causes the protons to flow back to the stroma thus breaking down the proton gradient.

The energy from this gradient breakdown is utilised by $A T P$ synthase to synthesise $A T P$ .

Assertion-Reason relation

The $A T P$ synthase ( $A T P$ ase) is a transmembrane enzyme that extends across the thylakoid membrane. It has two parts- $F_{0}$ and $F_{1}$ . The $F_{0}$ provides a channel for the protons to diffuse across the membrane. This facilitated diffusion happens due to the proton gradient created across the membrane.

Hence, assertion is correct but the reason is false.

Final answer

(C) If assertion is true but the reason is false.

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Similar questions

Q. Assertion :The proton gradient results in movement of protons across the membrane to stroma through the transmembrane channel of the

F_{0}

of the ATPase. Reason: This proton gradient leads to release of energy

Q. Assertion :The proton gradient is broken down due to the movement of protons across the membrane channel of the

F_{0}

of the ATPase Reason: It is the breakdown of proton gradient that leads to release of energy.

Q. Chemiosmosis, the generation of a proton gradient across the inner mitochondrial membrane, is a crucial requirement for the synthesis of ATP in cellular respiration.

How does the cell power the movement of protons up its gradient?

Which part of the ATPase enzyme forms a transmembrane channel in the thylakoid membrane which carries out facilitated diffusion of protons across the membrane?

Q. Assertion:

A T P

ase enzyme has two parts; one called the

F_{1}

is embedded in the membrane of thylakoid and forms a transmembrane channel that carries out facilitated diffusion of proton across the membrane.

Reason: The other portion is called

F_{0}

and protrudes on the thylakoid membrane on the side that faces stroma.

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ATP Synthase

Standard XII Biology

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Assertion: Chemiosmosis requires a membrane, a proton pump, a proton gradient and ATPase. Reason: The proton gradient is broken down due to movement of proton across the membrane to the lumen through the transmembrane channel of the F0 of the ATPase.

Assertion: Chemiosmosis requires a membrane, a proton pump, a proton gradient and $A T P$ ase.

Reason: The proton gradient is broken down due to movement of proton across the membrane to the lumen through the transmembrane channel of the $F_{0}$ of the $A T P$ ase.