Tag: digestion and absorption

Questions Related to digestion and absorption

Which of the following is the correct matching of the site of action on the given substrate, the enzyme acting upon it and the end product?
(i) Small intestine: Protein $\xrightarrow{Pepsin}$ Amino acid
(ii) Stomach : Fat $\xrightarrow{Lipase}$ Micelles
(iii) Duodenum : Triglycerides $\xrightarrow{Trypsin}$ Monoglyceride 
(iv) Buccal cavity : Starch $\xrightarrow{Amylase}$ Disaccharide
(v) Jejunum: Peptones $\xrightarrow{Pepsin}$ Amino acid
(vi) Buccal cavity : Starch $\xrightarrow{Amyloglycerate}$ Maltose

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

  1. (i),(ii) and (iii) are correct

  2. (iv) only 

  3. (iv) and (v) are correct

  4. All are correct

Show answer
Correct Option: B
Explanation:

(i) Pepsin digest protein in the stomach.

(ii)Lipase digest emulsified fat in the intestine.
(iii)In duodenum trypsin digest protein or dipeptides.
(iv) Starch is digested into maltose by salivary amylase in the buccal cavity.
(v)Pepsin digest protein in the stomach.
(vi) Starch is digested into maltose by salivary amylase in the buccal cavity.
So the correct option is '(iv) only '

Read the given statements and select the option that correctly identifies them as true or false
1) Insulin has no effect on absorption of glucose from gastrointestinal tract
2) Fat absorption is greatest in the upper part of the small intestine
3) most vitamins are absorbed in the ileum

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

  1. True

  2. False

Show answer
Correct Option: A
Explanation:
1) Insulin has no effect on the absorption of glucose from the gastrointestinal tract as it increases the amount of glucose absorption when its concentration increase in blood.
2) Fat absorption is greatest in the upper part of the small intestine because in duodenum bile emulsifies it and form micelles which are absorbed form.
3) Most vitamins are absorbed in the ileum.
So the correct option is 'True'.

What is common among amylase, renin and trypsin?

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

  1. They are proteins

  2. All these are proteolytic enzymes

  3. These are produced in stomach

  4. These act at the pH of less than 7

Show answer
Correct Option: A
Explanation:

A) Amylase is produced by buccal cavity, pancreas and intestine and digest starch.

B) Renin is produced by the stomach and helps in the digestion of milk in infants.
C) Trypsin is produced by the pancreas and helps in the digestion of protein.
But one thing is common in all the above three is that they are made up of proteins.
So, the correct option is 'They are proteins'.

If PH of stomach is made 7, which component of the food would be affected?

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

  1. Starch

  2. Proteins

  3. Fat

  4. Sucrose

Show answer
Correct Option: B
Explanation:

If pH of the stomach is made 7 protein digestion will affect as pepsin works ar pH of 2 to 3 and enzymes are highly precise about there function so it does not activate.

So the correct option is 'proteins'.

Chief function of HCl is ________

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

  1. To maintain a low pH to promote growth of microorganism

  2. To facilitate absorption

  3. To maintain low pH to activate pepsinogen to form pepsin

  4. To dissolve enzyme secreted in stomach

Show answer
Correct Option: C
Explanation:

The chief function of HCl in the stomatch is to maintain low pH to activate pepsinogen to form pepsin. HCl converts inactive pepsinogen into the active pepsin enzyme. The pepsin helps in the breaking down proteins in the stomach. HCl also kills bacteria that enter the stomach. It also helps in digestion of  other foods in the stomach.

Thus, the correct answer is 'To maintain low pH to activate pepsinogen to form pepsin.'

Which of the following statements are correct about the function of the acidic environment of the stomach?
(i) Provides defence against bacteria entering the digestive system
(ii) Converts pepsinogen to pepsin
(iii) Assists the breakdown of cells in animal and plant food stuffs

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

  1. ii only

  2. i and ii only

  3. ii and iii only

  4. i, ii, and iii

Show answer
Correct Option: B
Explanation:

The HCl is secreted by the oxyntic cells in the stomach. The HCl provides the acidic medium in the stomach that is responsible for converting the inactive pepsinogen to the active pepsin. Pepsin is required for protein digestion. The acidic medium provides defence against bacteria entering the digestive system.

Hence, the correct answer is 'i and ii only'

Which of the following enzymes is not useful in the digestion of proteins?

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

  1. Chymotrypsin

  2. Pepsin

  3. Trypsin

  4. Lipase

Show answer
Correct Option: D
Explanation:
  • Protein digestion occurs in the stomach and duodenum in which 3 main enzymes: Pepsin, trypsin and chymotrypsin.
  •  pepsin secreted by the stomach and trypsin and chymotrypsin secreted by the pancreas, break down food proteins into polypeptides that are then broken down by various exopeptidases and dipeptidases into amino acids. 
  • Hence, Lipase enzymes are not useful in the digestion of proteins.
  • So, the correct answer is 'Lipase'.

Where are proteins first digested in the alimentary canal?

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

  1. Small intestine

  2. Oesophagus

  3. Mouth

  4. Stomach

Show answer
Correct Option: D
Explanation:

The digestion of the food starts at the mouth where the enzyme amylase is secreted which digests the start that is present in the food and converts it into maltose. From there through the esophagus the food arrives in the stomach where it is stored for 4 hours and mixed with acid. The food when arrives at the stomach where the wall of the stomach secrets HCl with a pH of 1.8. This acid activates the inactive pepsinogen enzyme and forms active pepsin which digests proteins and converts them into proteases and peptides. From here the food moves to the small intestine where secretion from the liver and pancreas reach through a hepatopancreatic duct which is alkaline in nature and neutralizes the acidic food that comes from the stomach. Here majority of the digestion of protein to amino acids, fat to fat droplets, polysaccharides to monosaccharides etc takes place.


Therefore the correct answer is option D 

In the stomach proteins are hydrolysed by enzyme pepsin and $H^+$ to give-

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

  1. Peptones

  2. Proteoses

  3. Polypeptides

  4. $\alpha-$amino acids

Show answer
Correct Option: A
Explanation:

In the stomach, proteins are hydrolysed by enzyme pepsin. It begins the digestion of proteins by splitting them into peptones (see peptidase). It is produced by the action of $HCl\left( { H }^{ + } \right) $ on pepsinogen, which is secreted by the stomach in gastric glands.

Glucose is stored in the form of glycogen in ...

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

  1. stomach

  2. intestine

  3. liver

  4. pancreas

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Correct Option: A