The Fall and Expulsion

The fresco is a diptych, meaning that it is a singular art piece consisting of two adjoining panels.

The left part shows Adam and Eve preparing to take a bite from the forbidden fruit.
Luring them is the Serpent, with its half-human body coiled around the forbidden tree.
On the right, we see the an angel banishing Adam and Eve from the Garden of Eden.

Image source: Michelangelo, Public domain, via Wikimedia Commons