Tag: parts of the digestive system

Questions Related to parts of the digestive system

In which of the following structures protein digestion first occurs?

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

  1. Mouth

  2. Stomach

  3. Large intestine

  4. Small intestine

Show answer
Correct Option: B
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'.

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

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

  1. mouth

  2. stomach

  3. pancreatic duct

  4. small intestine

Show answer
Correct Option: B
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'.

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

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

  1. Pepsin

  2. Trypsin

  3. Salivary amylase

  4. Pancreatic amylase

Show answer
Correct Option: A
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'.

Pepsin is an enzyme which acts in

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

  1. acidic medium in the stomach

  2. alkaline medium in the stomach

  3. alkaline medium in the duodenum

  4. acidic medium in the duodenum

Show answer
Correct Option: A
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'.

Pepsin acts in

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

  1. basis medium

  2. acidic medium

  3. neutral medium

  4. all types of medium.

Show answer
Correct Option: B
Explanation:

Pepsin acts in 'acidic medium'.

So the correct option is B.

If pH of stomach is 1.6, then which enzyme will digest protein? 

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

  1. Amylase

  2. Trypsin

  3. Erypsin

  4. Pepsin

Show answer
Correct Option: D
Explanation:

If the pH of the stomach is 1.6, then 'pepsin' will digest protein.

So the correct option is D.

Digestion of which component of food will be affected if the pH of stomach is made 7?

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

  1. Fat

  2. Protein

  3. Sucrose

  4. Vitamins

Show answer
Correct Option: B
Explanation:

Digestion of 'proteins' will be affected if the pH of the stomach is made 7.

So the correct option is B.

Which of the following molecules is incorrectly paired with its source?

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

  1. Lysozyme-gastric juices

  2. Histamine-injured cells

  3. lnterferons-virus infected cells

  4. Immunoglobulins-plasma cells

Show answer
Correct Option: A
Explanation:

Histamine is an organic nitrogenous compound involved in local immune responses, as well as regulating physiological function in the gut and acting as a neurotransmitter for the brain, spinal cord, and uterus. Histamine is involved in the inflammatory response and has a central role as a mediator of itching. 

Interferons (IFNs) are a group of signaling proteins made and released by host cells in response to the presence of several viruses. In a typical scenario, a virus-infected cell will release interferons causing nearby cells to heighten their anti-viral defenses.
Immunoglobulins, also known as antibodies, are glycoprotein molecules produced by plasma cells (white blood cells). 
Lysozyme is a special enzyme found in tears, saliva, sweat, and other body fluids. Other mucosal linings, such as the nasal cavity, also contain lysozyme. It destroys bacteria that attempt to enter our body through these passageways. In the case of tears, they protect our eyes from bacterial invaders.

So, the correct option is 'Option A'.

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

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

  1. Chyle

  2. Chyme

  3. Bolus

  4. Chylomicron

Show answer
Correct Option: B
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'.

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

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

  1. Proteins in stomach

  2. Carbohydrates in duodenum

  3. Proteins in duodenum

  4. Carbohydrates in stomach

Show answer
Correct Option: A
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'.