Biology · Science General

Human Digestive System

1,953 Questions

The human digestive system explores the breakdown of biomacromolecules, covering organs from the stomach to the small intestine. It involves physiological processes like chyme movement, pH levels, and nutrient absorption in the gut. These fundamental biology concepts are regularly featured in medical and general science competitive exams.

Small intestine functionsBiomacromolecule breakdownStomach and digestionIntestinal bacteria

Human Digestive System Questions

Multiple choice

Secretion of gastric juice is controlled by

  1. gastrin

  2. cholecystokinin

  3. enterogastrin

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Gastrin is a peptide hormone that stimulates secretion of gastric acid (HCl) by the parietal cells of the stomach and aids in gastric motility. It is released by G-cells in the pyloric antrum of the stomach, duodenum and the pancreas.

Multiple choice

Most of the lysosomal enzymes function at

  1. acidic pH

  2. basic pH

  3. neutral pH

  4. any pH

  5. -
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

All the lysosomal enzymes are acid hydrolases, which are active at the acidic pH (about 5) that is maintained within lysosomes.

Multiple choice

A man cannot digest cellulose whereas cows can do so because

  1. their gut contains certain bacteria capable of digesting cellulose

  2. they have a many-chambered stomach

  3. they have efficient molars for grinding

  4. they produce an enzyme that can digest cellulose
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A man cannot digest cellulose whereas cows can do so because their gut contains certain bacteria capable of digesting cellulose.

Multiple choice

Trypsinogen (inactive trypsin) is secreted by

  1. duodenum

  2. liver

  3. pancreas

  4. stomach
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Trypsinogen (inactive trypsin) is secreted by pancreas. It is found in pancreatic juice, along with amylase, lipase and chymotrypsinogen. It is activated by enteropeptidase, which is found in the intestinal mucosa, to form trypsin. Once activated, the trypsin can activate more trypsinogen into trypsin. Trypsin cleaves the peptide bond on the carboxyl side of basic amino acids such as arginine and lysine. 

Multiple choice

What is peristalsis?

  1. Grinding of food by teeth

  2. Rhythmic wave-like movements of alimentary tract.

  3. The act of swallowing food.

  4. Churning of food by stomach

  5. Mixing of chewed food with enzymes.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Rhythmic wave-like movements of the food through the alimentary tract is called peristalsis.