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 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'.

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 helps in the digestion of food?

  1. Hormones

  2. Digestive juice

  3. Water

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

  • The process of digestion begins from the mouth itself and gets completed in small intestine.
  • Stomach plays a key role in the digestion of food. It has gastric glands which secrete gastric juices needed to break down food to simple nutrients and thereby contributing to digestion.
  • There are different hormones in our body that has different functions. For example, there could be pH changes associated with different types of food. This pH change stimulates the secretion of a hormone called gastrin which induces the production of digestive juices. But it is not directly connected to the digestion process.
  • Water is present in cell, organs and tissues to help regulating temperature and maintaining body functions.
  • Absorbed food enters the blood stream and is taken to different parts of the body.
So, the correct option is B.

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

Digestion is completed in

  1. Duodenum

  2. Ileum

  3. Stomach

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

Digestion is completed in the Ileum because it is the last part of small intestine where all the digestive secretions end. From the large intestine, the process of absorption occurs predominantly.

So, the correct option is B.

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

Enterokinase / enteropeptidase takes part in conversion of

  1. Pepsinogen to pepsin

  2. Trypsinogen to trypsin

  3. Protein into polypeptides

  4. Caseinogen into casein
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Enterokinase is an enzyme secreted by the intestinal mucosa that activates trypsinogen into its active form, trypsin.

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

Epithelial cells involved in absorption of digested food have on their free surface

  1. Zymogen granules

  2. Pinocytic vesicles

  3. Phagocytic vesicles

  4. Microvilli
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Microvilli are small projections on the surface of epithelial cells in the small intestine that significantly increase the surface area for nutrient absorption.

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

Cattle are able to digest cellulose which humans cannot because cattle have

  1. Cellulose digesting bacteria

  2. More efficient digestive system

  3. Large stomach

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

Cattle are ruminants that possess specialized bacteria in their rumen capable of breaking down cellulose, which humans lack.

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

Find out the correct sequence of substrate, enzyme and product

  1. $Small intestine : Proteins \xrightarrow{pepsin} Amino acids$
  2. $Stomach : Fats \xrightarrow{Lipase}micelles$
  3. $Duodenum : Triglycerides \xrightarrow{trypsin} Monoglycerides$
  4. $Small intestine : Starch \xrightarrow{a-amylase}Maltose$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The saliva contains an enzyme called salivary amylase which hydrolyses starch into maltose. The complete digestion of starch occurs only in the small intestine by the action of pancreatic amylase. The activity of enzymes is strongly affected by several factors, such as temperature and pH.


So, the correct option is 'Option D'.

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

If for some reason the parietal cells of the gut epithelium become partially nonfunctional, what is likely to happen

  1. Pancreatic enzymes, specially trypsin and lipase will not work efficiently

  2. Proteins will not be adequately hydrolysed by pepsin to proteoses and peptones

  3. pH of stomach will fall abruptly

  4. Steapsin will not be effective
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Parietal cells secrete hydrochloric acid (HCl), which is necessary to convert pepsinogen into active pepsin. Without HCl, protein digestion in the stomach is severely impaired.