ATP synthase, shown below, uses the proton (H ) gradient to drive ATP synthesis. Put the following steps of ATP synthesis in order from proton transport to the synthesis of ATP:
a. The y subunit rotates and interacts with the three alpha beta subunit pairs, causing confrontational changes in the beta subunit
b. protons from the intermembrane space bind to proton binding sites on c subunits
c. each beta subunit ADP and Pi, converts ADP + Pi to ATP, and releases ATP once during one turn of the y subunit
d. as the c ring rotates past the a subunit, c subunits release their protons into the matrix
e. the y subunit rotates along with the c subunit
b, d, e, a, c
b, d, e, a, c
b, d, e, a, c is the correct answer.
To put the steps of ATP synthesis in order, we need to understand the role of each subunit and their interactions. Here's the correct order:
b. Protons from the intermembrane space bind to proton binding sites on c subunits.
d. As the c ring rotates past the a subunit, c subunits release their protons into the matrix.
a. The y subunit rotates and interacts with the three alpha beta subunit pairs, causing confrontational changes in the beta subunit.
e. The y subunit rotates along with the c subunit.
c. Each beta subunit binds ADP and Pi, converts them to ATP, and releases ATP once during one turn of the y subunit.
Explanation:
- Step b: Protons from the intermembrane space bind to proton binding sites on the c subunits, creating a proton gradient across the membrane.
- Step d: As the c ring rotates, the c subunits release their bound protons into the matrix, driven by the proton gradient.
- Step a: The y subunit, which is attached to the c subunit, rotates and interacts with the alpha beta subunit pairs. This rotation causes conformational changes in the beta subunits.
- Step e: The y subunit rotates along with the c subunit due to the movement of the protons through the c ring.
- Step c: Each beta subunit binds ADP and Pi, converting them to ATP through the movement and conformational changes of the beta subunits. ATP is then released once during one turn of the y subunit.
By following this order, we can see how the proton gradient is utilized to drive the rotation and catalytic activity of ATP synthase, leading to ATP synthesis.