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

The principal action of the enterokinase present in the human intestinal juice is to-

  1. Hydrolyse casein into paracasein

  2. Act of the terminal peptide bond of peptide chain to release the last amino acid.

  3. Convert pro-carboxypeptidase to carboxypeptidase

  4. Activate the trypsinogen of the pancreatic juice.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Enterokinase (also called enteropeptidase) is a protease enzyme produced in the duodenum. Its primary and most important function is to activate trypsinogen (the inactive precursor) into trypsin by cleaving off an activation peptide. Trypsin then activates other pancreatic zymogens (procarboxypeptidase, chymotrypsinogen, etc.) creating a digestive enzyme cascade. Options A, B, and C describe functions of other enzymes.

Multiple choice

With reference to the human body, which one of the following statement is correct?

  1. Lipases are insoluble in water.

  2. Trypsin acts best in an acidic PH.

  3. Pepsin actions is enhanced in the duodenum by the alkalinity.

  4. Bile salts are steroids.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Bile salts are derived from cholesterol and have a steroid nucleus structure (cyclopentanoperhydrophenanthrene ring system). Lipases are water-soluble enzymes. Trypsin is a pancreatic enzyme that works best in alkaline pH of small intestine. Pepsin is denatured by the alkaline environment of duodenum.

Multiple choice

Pepsin is an enzyme found in humans. It was first crystallized by

  1. Theodor Schwann

  2. Louis Pasteur

  3. Robert Koch

  4. Paul Ehrlich
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

He was a German physiologist. He is famed for the development of cell theory, the discovery of Schwann cells in the peripheral nervous system, and the discovery and study of pepsin.

Multiple choice

The cells of pancreas are not autodigested by their enzymes as ___________.

  1. its cells are covered by mucus

  2. enzymes are secreted in their inactive forms

  3. enzymes are secreted in active form

  4. these enzymes do not have coenzymes

  5. autodigestion occurs but the cells are renewed many times in the pancreas
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This is true that enzymes secreted in the inactive form such as their pro form stops the autodigestion of pancreas from the active forms of the same enzymes.

Multiple choice

When a dilute solution of glucose reaches the small intestine it is _______.

  1. absorbed rapidly by active transport with sodium ions

  2. absorbed by facilitated diffusion like fructose

  3. lost with undigested food as its concentration is very low

  4. absorbed rapidly by passive transport

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

Glucose is rapidly absorbed in the small intestine along with sodium ions by the process called as active transport by co transport.

Multiple choice

When a woman takes dairy products she complains of diarrhoea and stomach aches. She does not complains when she consumes food other than the dairy products. She is suffering with deficiency of which of these enzymes?

  1. Renin

  2. Lactase

  3. Lipase

  4. Trypsin

  5. Ptyalin
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Any of a group of enzymes found in the small intestine, liver, and kidney of mammals that catalyze the breakdown of lactose (milk sugar) into the simple sugars.