Question

Which is the first enzyme to mix with food in the digestive tract?
a) Pepsin
b) Cellulase
c) Amylase
d) Trypsin

Answer 1

Hint: Digestion of food starts in the mouth itself. This enzyme hydrolyzes the starch in the ingested food particle.

Complete answer:
Salivary amylase is the first enzyme to mix with food in the digestive tract. It is the primary enzyme of saliva. Salivary amylase is secreted from the salivary glands (mainly parotid glands) in the buccal cavity. Salivary amylase breaks down starch into maltose, isomaltose, and limits dextrin. Approximately 30% of the starch is acted upon by salivary amylase. Salivary amylase acts up to the esophagus due to the presence of alkaline conditions. When the food reaches the stomach the action of salivary amylase becomes inactive due to the highly acidic medium.

Additional information
Apart from salivary amylase pancreatic amylase is also produced. Both the salivary and pancreatic amylases are α-amylases in case of human beings. The α-amylases (1,4-α-d-glucan glucanohydrolase and glycogen as) are found to be non-functional in the absence of calcium. α-amylase acts on long-chain carbohydrates breaking them into maltotriose (three glucose) and maltose (two glucose) from amylose and maltose, glucose, and dextrins (mixtures of polymers of d-glucose units linked by α-(1 → 4) or α-(1 → 6) bonds) from amylopectin by acting at random locations along the starch chain.

So, the correct answer is ‘Amylase’.

Note:
- Apart from digestive functions, salivary amylase aids in our dental health by preventing starches from accumulating on our teeth.
- Salivary amylase is also called ptyalin.
- Industrial amylase production can be achieved from Bacillus (bacteria).