Biology · Science General

Human Digestive System

2,002 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 bio-chemistry digestive system of human absorption of food absorption parts of the digestive system: structure and function

In jejunum, enzyme required for digestion of amino acid containing compounds is

  1. Trypsin

  2. Pepsin

  3. Peptidase

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

Peptidases are enzymes responsible for breaking down peptides into amino acids within the small intestine, including the jejunum. Trypsin and chymotrypsin are pancreatic proteases, while pepsin is a gastric enzyme.

Multiple choice bio-chemistry digestive system of human absorption of food absorption parts of the digestive system: structure and function

Digestion of carbohydrates occurs in

  1. Buccal cavity

  2. Stomach

  3. Intestine

  4. All the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Carbohydrate digestion begins in the buccal cavity with salivary amylase, continues in the intestine with pancreatic amylase, and involves various enzymes in the stomach lining or intestinal brush border. Therefore, all listed sites are involved in the process.

Multiple choice bio-chemistry digestive system of human absorption of food absorption parts of the digestive system: structure and function

Which is true about digestion and absorption of food?

  1. 60% starch is hydrolysed by salivary amylase

  2. Oxyntic cells secrete pepsinogen

  3. Chylomicrons are small lipoprotein particles passed in intestine into blood capillaries
  4. Fructose and amino acids area absorbed in intestine with the help of carrier ions of $Na^+$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Fructose and amino acids are absorbed in the small intestine via facilitated diffusion or secondary active transport, often coupled with Na+ ions. Option A is incorrect as salivary amylase hydrolyzes only about 30% of starch, and option B is incorrect because oxyntic cells secrete HCl.

Multiple choice bio-chemistry digestive system of human absorption of food absorption parts of the digestive system: structure and function

Absorption of glycerol, fatty acids and monoglycerides takes place by

  1. Lymph vessels within villi

  2. Walls of stomach

  3. Colon

  4. Capillaries within villi
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Fatty acids and glycerol are insoluble in water and are incorporated into micelles, then resynthesized into chylomicrons. These chylomicrons are transported into the lacteals, which are lymphatic vessels located within the intestinal villi.

Multiple choice bio-chemistry digestive system of human absorption of food absorption parts of the digestive system: structure and function

Which enzymes are likely to act on the baked potatoes eaten by a man, starting from mouth and as it moves down the alimentary canal

  1. Disaccharidase like maltase lipases nucleases

  2. Salivary amylase pancreatic amylase disaccharidases

  3. Salivary maltase carboxypeptidase trypsinogen

  4. Pancreatic amylase salivary amylase lipases
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Baked potatoes consist primarily of starch. Digestion begins in the mouth with salivary amylase, continues in the small intestine with pancreatic amylase, and concludes with disaccharidases (like maltase) in the brush border.

Multiple choice bio-chemistry digestive system of human absorption of food absorption parts of the digestive system: structure and function

Choose the correct answer from the allternatives given.
What is the name of the portion of alimentary canal which crushes the food ?

  1. Crop

  2. Gizzard

  3. Oesophagus

  4. Stomach
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Answer B: Gizzard

Stomach constructed of thick muscular walls is used for grinding up food, often aided by particles of stone or grit. In certain insects, the gizzard features chitinous plates or teeth.

Multiple choice bio-chemistry digestion absorption of food absorption parts of the digestive system: structure and function

Secretin is gastrointestinal tract hormone that

  1. Acts on exocrine part of pancreas and stimulates the secretion of water and bicarbonate ions

  2. Acts on exocrine portion of pancreas and stimulates the cells to secrete glucagon

  3. Acts on gastric glands and stimulates secretion of HCl and Pepsinogen

  4. Stimulates secretion of gastric lipase from stomach
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Secretin is released by the duodenum in response to acidic chyme. It travels through the blood to the pancreas, where it stimulates the secretion of water and bicarbonate ions to neutralize the acid.

Multiple choice bio-chemistry digestive system of human absorption of food absorption parts of the digestive system: structure and function

Which of the following is the primary absorptive process in the large intestine?

  1. Active transport of $Na^+$ from the lumen to the blood

  2. Absorption of amino acids and fructose

  3. Active transport of potassium from the lumen to the blood
  4. Active absorption of $HCO _3$ into the blood
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The primary function of the large intestine regarding absorption is the reabsorption of water and electrolytes, specifically the active transport of sodium ions from the lumen into the blood, which creates an osmotic gradient for water absorption.

Multiple choice zoology control and co-ordination in plants and animals the reflex action reflex action and reflex arc basic reflex action and reflex arc

Movement of food in the alimentary canal involves ................... movement.

  1. Voluntary

  2. Regulatory

  3. Involuntary

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

  • Digestion of food, contraction, and relaxation of blood vessels and many other movements are involuntary as we cannot really start or stop them simply by our will. 

Therefore, the correct answer is option C.

Multiple choice chemistry surface chemistry enzyme catalysis catalysis proteins and enzymes

The enzyme ptyalin used for digestion of food is present in:

  1. saliva

  2. blood

  3. intestine

  4. adrenal gland
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Enzymes are macromolecular biological catalysts. These are highly selective catalysts greatly accelerating both the rate and specificity of metabolic reactions. All enzymes are insoluble since they exist in the colloidal state. Urease is an enzyme that catalyzes the hydrolysis of urea, forming ammonia and carbon dioxide.
They decrease the activation energy by providing alternate pathway (enzyme reacts with the substrate to form an intermediate ES complex, which would be impossible in the absence of the enzyme) for the process.
Enzyme + Substrate → Complex → Product + Enzyme
Saliva is a watery substance located in the mouths of animals, secreted by the salivary glands. Human saliva is $99.5\%$ water, while the other $0.5\%$ consists of electrolytes, mucus, glycoproteins, enzymes and antibacterial compounds.
Digestive functions of saliva include moistening food and helping to create a food bolus. This lubricative function of saliva allows the food bolus to be passed easily from the mouth into the esophagus. Saliva contains the enzyme amylase, also called ptyalin, which is capable of breaking down starch into simpler sugars such as maltose and dextrin that can be further broken down in the small intestine. Only about $30\%$ starch digestion takes place in the mouth cavity.