Q.Draw a labeled sketch of a spermatozoan.

Step 1. Begin the sketch with an elongated cell enclosed by a single plasma membrane, divided into three clearly separated regions from front to back: head, neck (very short) and tail (the longest part).

Step 2. In the head, draw and label the flat, oval nucleus, with the acrosome as a small pointed cap over its tip (the acrosome is formed from the Golgi body and holds the enzyme hyaluronidase).

Step 3. At the neck, label the proximal centriole (nearer the nucleus) and the distal centriole (which gives rise to the tail's axial filament); immediately behind it, in the middle piece, draw the mitochondria wound tightly in a spiral (the mitochondrial spiral/nebenkern) around this axial filament. …

Build the sketch region by region (head, neck, middle piece, tail), labelling e …

• Placing the mitochondria in the head instead of the middle piece. …