Question

Which one of the following is the first enzyme to mix with food in the digestive tract?
1. Trypsin
2. Cellulose
3. Pepsin
4. Amylase
5. None of the above/More than one of the above.

Answer 1

Correct Answer - Option 4 : Amylase

The correct answer is Amylase.

• Salivary amylase
  • It is the first enzyme to mix with food in the digestive tract. Hence, Option 4 is correct.
  • 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.

• Trypsin
  • It is a serine protease from the PA clan superfamily, found in the digestive system of many vertebrates, where it hydrolyzes proteins.
  • Trypsin is formed in the small intestine when its proenzyme form, the trypsinogen produced by the pancreas, is activated.
• Cellulose
  • It is an organic compound with the formula (C₆H₁₀O₅)_n
  • It is a polysaccharide consisting of a linear chain of several hundred to many thousands of β linked D-glucose units.
  • Cellulose is an important structural component of the primary cell wall of green plants, many forms of algae, and the oomycetes.
• Pepsin
  • It is an endopeptidase that breaks down proteins into smaller peptides.
  • It is produced in the gastric chief cells of the stomach lining and is one of the main digestive enzymes in the digestive systems of humans and many other animals, where it helps digest the proteins in food.