When an enzyme is competitively inhibited, which of the following changes occur?
Features of noncompetitive inhibition:

Inhibitor have no structural resemblance to substrate.
Most irreversible (Except a few reversible non-competitive inhibition).
Excess substrate do not abolish the inhibition.
Km remains the same.
Vmax decreases.

 
Features of competitive inhibition:

Inhibitor will be structural analogue of substrate.
Reversible 
Excess substrate abolish the inhibition.
Km increases.
Vmax remains the same.
The apparent Km is unchanged.
The apparent Km is decreased.
Vmax is decreased.
Vmax is unchanged.