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 bio-chemistry coordination in life processes role of intestine digestion in intestine mechanism of digestion digestive system - organs

Maximum digestion of food takes place in

  1. Stomach

  2. Jejunum

  3. Colon

  4. Duodenum
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
  • Small intestine has three parts - duodenum, jejunum, and ileum. 
  • The maximum digestion of food takes place in the duodenum. While the digestion of food is completed in jejunum.
  •  The maximum absorption of food takes place in ileum.
Multiple choice bio-chemistry coordination in life processes role of intestine digestion in intestine mechanism of digestion digestive system - organs

Which one of the following pairs of the cells with their secretion is correctly matched?

  1. Oxyntic cells- A secretion with pH between 2.0 and 3.0

  2. Alpha cells of Islets of Langerhans- Secretion that decreases blood sugar level

  3. Kupffer cells- A digestive enzyme that hydrolysis nucleic acids

  4. Sebaceous glands- A digestive enzyme that hydrolysis nucleic acids
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Oxyntic cells or parietal cells, are the stomach epithelium cells that secrete gastric acid intrinsic factor. These cells secrete hydrochloric acid (HCl), which makes the gastric juice acidic (pH =2 -3). 

Oxyntic cells  are the epithelial cells that secrete hydrochloric acid (HCl) and intrinsic factor. These cells are located in the gastric glands found in the lining of the fundus and in the body of the stomach.
Alpha cells of islets of Langerhans secretes glucagon hormone, which increase the glucose level in the blood by converting glycogen to glucose in liver cells. 

Kupffer cells are specialized cells in the liver that destroy bacteria, foreign proteins and worn-out blood cells. 
Sebaceous glands and microscopic glands in the skin that secrete an oily/waxy matter (called as sebum) to lubricate the skin and hair of mammals.

Therefore, the correct answer is option A.

Multiple choice bio-chemistry coordination in life processes role of intestine digestion in intestine mechanism of digestion digestive system - organs

Which of the following best represents the enzyme composition of pancreatic juice?

  1. Amylase, peptidase, trypsinogen, rennin

  2. Lipase, amylase, trypsinogen, peptidase

  3. Lipase, amylase, pepsin, maltase

  4. Peptidase, amylase, pepsin, rennin
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Pancreatic juice is liquid secetrted by pancreas . It is alkaline in nature and it has following enzymes lipase, for digesting fats, amylase for digesting starch, trypsinogen for digesting proteins.

Multiple choice bio-chemistry coordination in life processes role of intestine digestion in intestine mechanism of digestion digestive system - organs

The end products of protein digestion are

  1. monosaccharides

  2. steroids

  3. amino acids

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

  1. Amino acids and proteins are the building blocks of life. Amino acids are organic compounds that combine to form proteins.
  2.  When proteins are digested or broken down, amino acids are left. Zymogenic cell or peptic cell in the stomach that releases pepsinogen and chymosin. 
  3. This inactive pepsinogen, on exposure to hydrochloric acid, gets converted to the active enzyme pepsin.
  4.  Pepsin is produced in the stomach and is one of the main digestive enzymes, which helps in digestion of the proteins to polypeptide chains. The end product of protein is it must be broken down into amino acids. Hence, the end product of protein digestion is amino acids.
So, the correct answer is 'amino acids'.

Multiple choice bio-chemistry coordination in life processes role of intestine digestion in intestine mechanism of digestion digestive system - organs

A pancreatic zymogen secreted into the duodenum, can be activated by:-

  1. trypsin

  2. pepsin

  3. secretin

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

Enteropeptidase is an enzyme produced by the cells of the duodenum and is involved in the digestion in humans and other animals. Enteropeptidase converts trypsinogen (a zymogen) into its active form trypsin, resulting in the subsequent activation of pancreatic digestive enzymes

So, the correct answer is 'trypsin'

Multiple choice bio-chemistry coordination in life processes role of intestine digestion in intestine mechanism of digestion digestive system - organs

If for some reason the parietal cells of the gut epithelium become partially non-functional, what is likely to happen? 

  1. The pancreatic enzymes and specially the trypsin and lipase will not work efficiently.

  2. The pH of stomach will fall abruptly.

  3. Steapsin will be more effective.

  4. Proteins will not be adequately hydrolysed by pepsin into proteoses and peptones.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Parietal cells secrete HCl and intrinsic factor. Parietal glands also secrete pepsinogen to which hydrochloric acid acts to convert it into pepsin. Pepsin in return causes digestion of protein. If parietal cells become non-functional, it will directly affect protein digestion. So, the correct answer is (d).

Multiple choice bio-chemistry coordination in life processes role of intestine digestion in intestine mechanism of digestion digestive system - organs

When the acidic food from stomach comes to small intestine which of the following acts on it to make it alkaline?

  1. Bile

  2. Trypsin

  3. Pepsin

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • The pancreatic enzymes and intestinal enzymes are optimally active in alkaline pH (8.0-8.4) in the small intestine.
  • Thus, the acidic food from stomach is made alkaline by the action of bile.
  • Bile is alkaline in nature as it contains organic salt known as bile salt.
Multiple choice bio-chemistry digestive system of human role of intestine digestion in intestine mechanism of digestion

Protein digesting enzyme is

  1. Pepsin

  2. Ptyalin

  3. Amylase

  4. Maltase

  5. Sucrase
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  1. Pepsin is produced in the stomach and is one of the main digestive enzymes, which helps in digestion of the proteins in food. Zymogenic cell or peptic cell is a cell in the stomach that releases pepsinogen and chymosin.
  2.  The inactive pepsinogen, on exposure to hydrochloric acid, gets converted to the active enzyme pepsin, the proteolytic enzyme of the stomach. Pepsin converts proteins into proteoses and peptones (peptides). 
  3. Pepsin hydrolyses proteins to polypeptide chains and initiates protein digestion  Hence, the protein-digesting enzyme is pepsin.
So, the correct answer is 'pepsin'.
Multiple choice bio-chemistry digestive system of human role of intestine digestion in intestine mechanism of digestion

I. Amylase
II. Lipase
III. Pepsin
IV. Trypsin

Out of the aforementioned enzymes, the protein-digesting enzymes are

  1. I and II.

  2. I and III.

  3. II and III.

  4. II and IV.

  5. III and IV.
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Protein digestive enzymes are pepsin and trypsin. They break down proteins into smaller peptides and amino acids. Pepsin is secreted by the gastric gland in the stomach where as trypsin is secreted by Pancreas.

Amylase and Lipase are other important digestive enzymes as well and they help in digestion of starch and fats respectively. Hence option E is correct.

Multiple choice zoology the endocrine system introduction to human endocrine system endocrine system and hormone coordination in human beings- chemical control

All functions of the body are regulated and integrated by

  1. Respiratory system

  2. Digestive system

  3. Neuroendocrine system

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

Hormones are used to communicate between organs and tissues to regulate physiological and behavioral activities, such as digestion, metabolism, respiration, tissue function, sensory perception, sleep, excretion, lactation, stress, growth and development, movement, reproduction, and mood.

Multiple choice bio-chemistry the muscular system and digestive system in human beings busy at work - our internal organs skeletal and digestive system from tasting to digestion types of ecological pyramids introduction to human digestive system

Which of the following is true about digestion and absorption of food?

  1. Trypsin, chymotrypsin and carboxypeptidase are brush border enymes
  2. The chemical process of digestion is initiated in the oral cavity. A bout $60\%$ starch is hydrolysed here by salivary amylase to form maltose

  3. Rennin is proteolytic enzyme found in grastic juice of infants. Small amounts of lipases are also secreted by the gastric glands

  4. If breast feeding is replaced by less nutritive food low in proteins and calories, the infants below the age of one year will suffer from kwashiorkar
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Rennin is a proteolytic enzyme present in the gastric secretion of infants that allows digestion of milk products. Small amounts of Gastric Lipase is also secreted by the gastric glands.
So, the correct option is 'Rennin is proteolytic enzyme found in grastic juice of infants. Small amounts of lipases are also secreted by the gastric glands'.