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 biology photosynthesis site of photosynthesis chloroplast and pigments of photosynthesis pigments action spectrum and absorption spectrum spectrum of electromagnetic radiation

Consider following statements A & B
A - The enzyme acts on 'N' terminal of polypeptide chain
B - The enzyme acts on 'C' terminal of a polypeptide chain
Choose the correct option w.r.t the digestive juices which contain these enzymes

  1. A- Succus entericus B - Pancreatic juice

  2. A - Intestinal juice B - Bile juice in duodenum

  3. A - Pancreatic juice B - Intestinal juice

  4. A - Intestinal juice B - Gastric juice
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Carboxypeptidases (C-terminal) are found in pancreatic juice. Aminopeptidases (N-terminal) are found in intestinal juice (succus entericus).

Multiple choice biology cell structure animal cell plant and animal cell cell structure and micro-organisms

The finger-like projections which increase the surface area in the small intestine are called ..........

  1. Pseudopodia

  2. Villi

  3. Lumen

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

  • Pseudopodia are temporary protrusions that are filled with cytoplasm within the eukaryotic amoeboid cells and unicellular protists. Pseudopodia, also called as "false foot" are majorly used for movement and ingestion of food, nutrients and other particulate matter.
  • Villi are the finger-like projections within the small intestine that help in the absorption of nutrients from the digested food by increasing the surface are of intestine walls.
  • Lumen is the inside space of the gastrointestinal tract, through which the food is transported while digesting from mouth to anus.
Thus the correct answer is 'Villi'.

Multiple choice biology cell structure animal cell plant and animal cell cell structure and micro-organisms

Functional units of food absorption are

  1. Villi

  2. Brunners glands

  3. Crypts of Lieberkuhn

  4. Peyers patches
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
The villi and microvilli, with their many folds with finger-like projection, present on the lining of the small intestine, increase the surface area of the intestine for more absorption of the nutrients. The microvilli have protein channels and pumps in their membranes to allow the rapid absorption of food by facilitated diffusion and active transport. Also, the villi contain an epithelial layer, which is only one cell layer thick so that food can pass through easily and be absorbed quickly. This thin layer of cells contains mitochondria to provide the ATP needed for the active transport of certain food molecules. Finally, there is a lacteal branch at the centre of the villus, which carries away fats after absorption.
So, the correct answer is option A.
Multiple choice biology what do animals eat? introduction to animal nutrition food for life types of nutrition

Various steps of human nutrition are in the order 

  1. Ingestion, egestion, digestion, absorption and assimilation

  2. Ingestion, egestion, assimilation, absorption and assimilation

  3. Ingestion, assimilation, digestion, absorption and egestion

  4. Ingestion, digestion, absorption, assimilation and egestion
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

  • There are five steps in the process of Nutrition in animals. 
  1. Ingestion: The process of taking in food into the body is called Ingestion.
  2. Digestion- It involves the break down of nutrients such as proteins into amino acids, carbohydrates into starch and fats into fatty acids and glycerol.
  3. Absorption- It involves the absorption of nutrients from the food by blood.
  4. Assimilation- It involves the process of transporting nutrients and water to all parts of the body by blood.
  5. Egestion- It involves the disposal of waste food out from the body. Hence, Various steps of human nutrition are in the order are  Ingestion, digestion, absorption, assimilation and egestion.
So, the correct answer is 'Ingestion, digestion, absorption, assimilation and egestion'.

Multiple choice biology what do animals eat? introduction to animal nutrition food for life types of nutrition

The breakdown of complex components of food into simple ones is called as

  1. Respiration

  2. Digestion

  3. Excretion

  4. Absorption
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Digestion is the process of conversion of complex food substances into simpler absorbable substances. It is carried out by our digestive system by mechanical and biochemical methods.
So, the correct answer is 'Digestion'.
Multiple choice biology what do animals eat? introduction to animal nutrition food for life types of nutrition

The process of expelling of food in amoeba 

  1. Egestion

  2. Digestion

  3. Nutrition

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
When a sufficient amount of undigested food gets collected in the food vacuole, it is thrown out of the body by rupturing cell membrane. The process of removal of undigested food from the body is called egestion.
So, the correct option is 'Egestion'.
Multiple choice biology what do animals eat? introduction to animal nutrition food for life types of nutrition

Which of the following phenomena helps in the degradation of complex substances of food into simpler ones?

  1. Digestion

  2. Ingestion

  3. Excretion

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

The process in the alimentary canal by which food is broken up physically, as by the action of the teeth, and chemically, as by the action of enzymes, and converted into a substance suitable for absorption and assimilation into the body.


So, the correct option is 'Digestion'.

Multiple choice bio-chemistry digestive system of human absorption mechanism absorption digestion

.......... is the form in which digested fats are absorbed into the intestinal walls.

  1. Chylomicrons

  2. Micelles

  3. Bile salts

  4. Both A and B
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Micelles are formed when bile emulsifies the fat which makes it water soluble and can be absorbed by the intestinal wall. Later on, they convert into chylomicrons by coating them with proteins are absorbed by the lymph vessels which transport it into a blood and then it reaches the cell.

So the correct option is 'Micelles'.

Multiple choice bio-chemistry digestive system of human absorption mechanism absorption digestion

The villi present on the wall of the small intestine

  1. Secretes digestive enzyme

  2. Increase surface area for absorption

  3. Hold mucus to protect wall

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation


  • Villi present in small intestine increase intestinal absorptive surface area providing efficient absorption of nutrients in lumen.
  • Mucosa is an innermost layer of tissues seen in the small intestine and is a mucous membrane that secretes digestive enzymes and hormones.
  • A submucosa layer provides blood vessels, nerves and lymphatic vessels to support mucosa on the surface to protect the wall.
So the correct answer is 'Increase surface area for absorption'.

Multiple choice bio-chemistry digestive system of human absorption mechanism absorption digestion

Absorption of nutrients
Read the following four statements (i) - (iv) with certain mistakes in two of them.
(i) Fructose is generally absorbed by simple diffusion.
(ii) The digestive wastes, solidified into coherent faeces in the rectum initiate an endocrinal action causing an urge or desire for its removal.
(iii) The food mixes thoroughly with the acidic gastric juke of the stomach by the churning movements of its muscular wall and is called the chyme.
(iv) The secretions of the brush border cells of the mucosa alongwith the secretions of the goblet cells constitute the succus entericus.
Which of the above two statements have mistakes?

  1. (i) and (ii)

  2. (ii) and (iii)

  3. (iii) and (iv)

  4. (i) and (iii)
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Statement (i) is incorrect because fructose is absorbed by facilitated diffusion, not simple diffusion. Statement (ii) is incorrect because the urge for defecation is initiated by stretch receptors in the rectal wall, not an endocrinal action.

Multiple choice bio-chemistry digestive system of human absorption mechanism absorption digestion

The absorption of glycerol, fatty acids and monoglycerides takes place by the

  1. Wall of the stomach

  2. Lymph vessels within the villi

  3. Capillaries within the villi

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

Each villus has a network of capillaries and fine lymphatic vessels called lacteals close to its surface. The epithelial cells of the villi transport nutrients from the lumen of the intestine into these capillaries (amino acids and carbohydrates) and lacteals (lipids). The absorbed substances are transported via the blood vessels to different organs of the body, where they are used to build complex substances such as the proteins required by our body. The food that remains undigested and unabsorbed passes into the large intestine.

Multiple choice bio-chemistry digestive system of human absorption mechanism absorption digestion

Which of the following nutrient is absorbed by the active absorption?

  1. Amino acids

  2. Glucose

  3. Fatty acids

  4. Both A and B
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Absorption is a process by which the end products of digestion pass from the alimentary canal into the blood and lymph through intestinal mucosa. It is carried out by the passive, active and facilitated type of transport mechanism.
Active transport mechanism occurs against the concentration gradient and is involved in the absorption of amino acids, monosaccharides like glucose, and electrolytes like Na+.
So the correct answer is 'Both A and B'.
Multiple choice bio-chemistry digestive system of human absorption mechanism absorption digestion

Fats are mostly absorbed in

  1. Duodenum

  2. Jejunum

  3. Ileum

  4. Both A and B
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
The small intestine is the main site for absorption of nutrients and digestion of fat. Fats are consist of glycerol and fatty acids. They are mostly absorbed in duodenum and jejunum part of the small intestine. Duodenum is the upper portion of the intestine that gives hormonal signal whereas jejunum has microvilli that help in increasing the surface area for the absorption of fats.
So the correct answer is 'Both A and B'.
Multiple choice biology chemical coordination and integration kidney hormones coordination in human beings- chemical control endocrine system in humans

Which one of the following is incorrectly matched?

  1. Renin- Liver

  2. Ptyalin- Mouth

  3. Pepsin- Stomach

  4. Trypsin- Intestine
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

  • Renin, also known as an angiotensinogenase, is an aspartic protease protein.
  • This enzyme is secreted by the kidneys that participate in the body's renin–angiotensin–aldosterone system (RAAS)  that mediates the volume of extracellular fluid (blood plasma, lymph and interstitial fluid), and arterial vasoconstriction. 
  • Thus, it regulates the body's mean arterial blood pressure. Hence, renin is not secreted by the liver.
So, the correct answer is 'Renin- Liver'.