Place the three sentences from the list into the correct order to describe the s
ID: 33091 • Letter: P
Question
Place the three sentences from the list into the correct order to describe the synthesis of ATP by ATP synthase. Only three sentences are accurate...
The B subunit converts from the O to the T conformation; ATP is released.
The B subunit converts from the L to the T conformation; ATP is synthesized from ADP and phosphate.
The B subunit is converted from the T to the O conformation. ATP is released.
The B subunit changes from the L to the T conformation; ATP is hydrolyzed to ADP and phosphate.
Subunit converted from T to O conformation; ADP and phosphate are able to bind.
ADP and phosphate bind to O site.
ATP from surrounding medium binds to O site.
My hint: Check that you have placed only three phrases. Recall that the O conformation of a ? subunit has low affinity for binding ADP or ATP; the T conformation is active and has high affinity for adenine nucleotides. In the diagram, the O conformation is shown in green, the L conformation is shown as blue, and the T conformation is colored purple. Step 1) ATP and Pi must bind to the enzyme. Consider the conformation of the ? subunit where they bind. Step 2) Think about what happens after ATP and Pi bind to a ? subunit and the subunit changes conformation. Step 3) Which conformation
Explanation / Answer
The correct order to describe the synthesis of ATP by ATP synthase:
1.Subunit converted from T to O conformation; ADP and phosphate are able to bind.
2.The B subunit converts from the L to the T conformation; ATP is synthesized from ADP and phosphate.
3. The B subunit is converted from the T to the O conformation. ATP is released.
Explanation: The "O" conformation ("open") has very low affinity for the adenine nucleotide substrates (ATP or ADP). The "L" conformation ("loose") has moderate affinity for substrates, but (like the O conformation) is catalytically inactive. Finally, the "T" conformation ("tight") has high substrate affinity and is catalytically active. The catalytic activity of the ? subunit is of course the reaction ADP + Pi = ATP + H2O.
Once ATP is released from the subunit in the O conformation, ADP + Pi can then bind the vacated site, and the same sequence can be repeated with the next 120