Caring for the concept of synchronization with WMQ

I am a little confused in from WebSphere MQ. According to the link from the WMQ Infocenter, the synchronization point is defined below: syncpoint

The decision to commit or cancel changes is made in the simplest case at the end of the task. However, it may be more useful for the application to synchronize data changes at other logical points in the task. These logical points are called synchronization points (or synchronization points), and the processing period for a set of updates between two synchronization points is called a unit of work.

Therefore, it is called processing between two synchronization points. In my opinion, this unit of work is actually a transaction. Therefore, I paint a picture reflecting the relationship between them: a unit of work

• ?
• , , , , ?