Question

Acrosome reaction in sperm is triggered by

• A. Capacitation
• B. Release of lysine
• C. Influx of $N{a}^{+}$
• D. Release of fertilizin

Answer 1

The correct option is C Influx of $N{a}^{+}$

The activated spermatozoon on reaching the egg plasma membrane, undergoes a number of changes in its acrosomal region. All these changes are collectively described under acrosome reaction. Acrosome reaction is calciuim-dependent involving massive uptake of calcium and sodium with an efflux of hydrogen, generating high pH and osmotic pressure, producing negative surface charge, and partial or total release of the acrosomal enzymes. Calcium influx may activate phospholipase resulting in accumulation of unsaturated fatty acids and fusiogenic lysophospholipids contributing to acrosome reaction.