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 parts of the digestive system digestive system of human human digestive system digestion and absorption biology nutrition deficiency diseases digestive system

Enzyme pepsin in the gastric juice helps in the digestion of :-

  1. carbohydrates

  2. fats

  3. nucleic acids

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

Pepsin is the chief digestive enzyme in the stomach that stomach that breaks down proteins. Cells produce pepsinogen that is produced to act on mucus by epithelial cells of the stomach that helps to protect the lining of the stomach from corrosive hydrochloric acid and pepsin.

So, the correct option is 'Proteins'.

Multiple choice parts of the digestive system digestive system of human human digestive system digestion and absorption biology nutrition deficiency diseases digestive system

In which of the following structures protein digestion first occurs?

  1. Mouth

  2. Stomach

  3. Large intestine

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

  • Digestion involves the mixing of food, its movement through the digestive tract, and the chemical breakdown of the large molecules of food into smaller molecules.
  •  Digestion begins in the mouth when we chew and swallow, and then it is passed on to the stomach where digestion takes place by gastric juices and enzymes secreted by the stomach and then it is passed to the small intestine where the digestion is completed. 
  • Pepsin is an enzyme which is released by zymogenic cells, the chief cells in the stomach and that degrades food proteins into peptides. Hence, the stomach is the structure where the protein digestion first occurs.
So, the correct answer is 'Stomach'.

Multiple choice parts of the digestive system digestive system of human human digestive system digestion and absorption biology nutrition deficiency diseases digestive system

A digestive juice with a pH of approximately 2 is found inside the

  1. mouth

  2. stomach

  3. pancreatic duct

  4. small intestine
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  • The pH of your stomach varies, from 1-2 up to 4-5. When you eat, the stomach releases enzymes called proteases as well as hydrochloric acid to help in digestion.
  • By itself, the acid doesn't really do much for digestion, but the proteases that cleave proteins work best in an acidic environment or low pH, so after a high-protein meal, your stomach pH may drop to as low as 1 or 2. 
  • However, buffers quickly raise the pH back to 3 or 4. After the meal has been digested, your stomach pH returns to a resting level of about 4 or 5. Hence, inside of the stomach, a digestive juice with a pH of approximately 2 is found.
So, the correct answer is 'stomach'.
Multiple choice parts of the digestive system digestive system of human human digestive system digestion and absorption biology nutrition deficiency diseases digestive system

Choose the correct answers from the alternatives given.
Which of the following enzymes has the lowest pH optimum?

  1. Pepsin

  2. Trypsin

  3. Salivary amylase

  4. Pancreatic amylase
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • In humans and other mammals pepsin produced in the stomach by chief cells in an inactive form called pepsinogen. 
  •  Once the pepsinogen is released into the stomach, the low pH from the gastric acid helps in the conversion of pepsinogen into pepsin, the active enzyme.
  •  Many proteins are denatured at low pH, and most enzymes whether or not they denature require a higher pH for activity. Hence, pepsin is the enzymes has the lowest pH optimum.
So, the correct answer is 'pepsin'.
Multiple choice parts of the digestive system digestive system of human human digestive system digestion and absorption biology nutrition deficiency diseases digestive system

Pepsin is an enzyme which acts in

  1. acidic medium in the stomach

  2. alkaline medium in the stomach

  3. alkaline medium in the duodenum

  4. acidic medium in the duodenum
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

  • Pepsin is an enzyme which is released by zymogenic cells, the chief cells in the stomach and that degrades food proteins into peptides.
  •  It is most active in acidic environments.
  •  It exhibits maximal activity at pH 2.0 and is inactive at pH 6.5. Hence, Pepsin is an enzyme which acts in an acidic medium in the stomach.
So, the correct answer is 'acidic medium in the stomach'.

Multiple choice parts of the digestive system digestive system of human human digestive system digestion and absorption biology nutrition deficiency diseases digestive system

Partially digested semisolid food formed in stomach is ...........

  1. Chyle

  2. Chyme

  3. Bolus

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

Chyme is the name given to the partially digested food, formed in the stomach and enters into the small intestine(duodenum) via the pyloric valve. Chyme, also known as chymus has the consistency of oatmeal(semisolid). Chyme is a thick semisolid mass of partially digested food and digestive secretions during the digestion process. Hence, partially digested semisolid food in the stomach is chyme.

So, the correct answer is 'Chyme'.

Multiple choice parts of the digestive system digestive system of human human digestive system digestion and absorption biology nutrition deficiency diseases digestive system

Pepsin digests .............. .

  1. Proteins in stomach

  2. Carbohydrates in duodenum

  3. Proteins in duodenum

  4. Carbohydrates in stomach
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Pepsin is produced in the stomach and is one of the main digestive enzymes in the digestive systems of humans and many other animals, where it helps digest the proteins in food. Zymogenic cell or peptic cell is a cell in the stomach that releases pepsinogen and chymosin.

The proenzyme pepsinogen(inactive), on exposure to hydrochloric acid, gets converted to the active enzyme pepsin. Pepsin hydrolyses proteins to polypeptide chains and initiates protein digestion in the digestion process in humans. Hence, the pepsin digests protein in the stomach.

So, the correct option is 'proteins in the stomach'.

 

Multiple choice biology constitutes of diet role of vitamins functions and principal sources of vitamins and minerals digestive disorders need for nutrients

Consider the following statements:
(I) The pellagra vitamin is nicotinamide present in milk, yeast, meat and leafy vegetables.
(II) Crypts of Lieberkuhn are present in the liver.
(III) Steapsin is the pancreatic amylase.

  1. I and II are correct.

  2. II and III are correct.

  3. I and III are incorrect.

  4. I and II are incorrect.

  5. I, II and III incorrect.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Nicotinamide or Niacin is also known as anti pellagra vitamin. It is a component of NADP, NADP+ and is important for energy transfer reactions. Yeast, pulses, green vegetables, cereals, milk, egg yolk, liver, milk, fish, meat are rich sources of niacin. Crypts of lieberkuhn occur throughout small intestine and produce intestinal juice or succus entericus. Steapsin is pancreatic lipase and acts on fats and converts fats into fatty acids, glycerol, mono and diglycerides.

Multiple choice biology constitutes of diet role of vitamins functions and principal sources of vitamins and minerals digestive disorders need for nutrients

Which of the following are absorbed in the alimentary canal?

  1. Albumin of egg

  2. Polysaccharides

  3. Fat soluble vitamins

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

Monoglycerides and fatty acids enter absorptive cells in the small intestine through micelles; they leave micelles and recombine into chylomicrons, which then enter the bloodstream. Fat soluble vitamins are absorbed in the same manner as lipids; water soluble vitamins can be directly absorbed into the bloodstream from the intestine.

Multiple choice chemistry introduction to acid and base neutralisations in everyday life acids and bases in daily life neutralisation reaction

Indigestion is painful so to relieve indigestion, we take an antacid such as milk of magnesia , which 
contains :

  1. magnesium hydroxide

  2. hydrochloric acid

  3. tartaric acid

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

Milk of magnesia (also known as magnesium hydroxide; $ { Mg }{ (OH) } _{ 2 } $) is basic in nature and one of the most important ingredients of an antacid. 


The hydroxide ions from $ { Mg }{ (OH) } _{ 2 } $) undergo neutralisation with $ { H }Cl $ in the stomach produced during indigestion or gastric problems, to produce water. Equation is as follows :

$ \quad 2HCl\quad +\quad Mg{ (OH) } _{ 2 }\quad \rightarrow \quad Mg{ (Cl) } _{ 2 }\quad +\quad 2{ H } _{ 2 }O $


Hence the option A is correct.

Multiple choice biology the nervous system the reflex action reflex action and reflex arc basic reflex action and reflex arc

Pavlov's pouch is

  1. An artificial stomach

  2. A bag containing digestive enzymes

  3. A bag containing food

  4. Opened stomach of a dog
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
  • Pavlov's Pouch is an artificially created pouch for experimental purposes.
  • It was surgically created by a physiologist Ivan Petrovich Pavlov.
  • It was created to study the physiology of the digestive tract.
  • It was also used to study the principles of secretion of the fundal glands.
  • It is a small portion of the stomach which is separated from the main stomach of a dog.
  • So, the correct answer is 'Opened stomach of a dog'.
Multiple choice zoology excretion and osmoregulation micturition urine and urine formation urine formation

After having lunch or dinner one can feel to pass urine, because of the

  1. Stomach pressures on bladder

  2. Solids become liquids

  3. Water content in food material

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

The feeling to pass urine after a meal is often associated with the increased fluid intake from food and beverages, which increases the volume of urine produced.