Q.List the chemical changes that starch molecule undergoes from the time it reaches the small intestine.

Step 1. Recall the state of starch on arrival: any starch not already broken down by salivary amylase (ptyalin) in the mouth reaches the small intestine still largely as starch or partially converted disaccharide.

Step 2. Apply pancreatic amylase: this enzyme, secreted in pancreatic juice, converts starch (and glycogen) into the disaccharide maltose, working in the alkaline medium provided by pancreatic bicarbonate.

Step 3. Apply intestinal maltase: maltase, part of the intestinal juice (succus entericus) secreted by Brunner's glands and the intestinal glands, hydrolyses maltose into two molecules of glucose. …

Trace the starch molecule step by step through the two-enzyme breakdown sequence (pancreatic amylase, then intestinal m …

• Stopping at maltose and forgetting the final maltase step that yields glucose, the actual absorbable unit. …