It is possible to perceive depth with one eye closed because of

monocular cue

Explanation:

The key reason one don't lose sense of depth is because of monocular cue. Our brain can still detect the actual position of the object with helps of cues even if one eye is closed.

Such cues include (but are not limited to):

Hence, Monocular Cues are used by using one eye to help sense distance.

enzyme active site and substrate specificity

enzymes bind with chemical reactants called substrates. there may be one or more substrates for each type of enzyme, depending on the particular chemical reaction. in some reactions, a single-reactant substrate is broken down into multiple products