Tag: bio-chemistry

Questions Related to bio-chemistry

What percentage of amino acids is absorbed in the small intestine?

bio-chemistry digestive system of human absorption of food absorption parts of the digestive system: structure and function

  1. 15%

  2. 30%

  3. 100%

  4. 90-95%

Show answer
Correct Option: D
Explanation:

Initiation of protein digestion starts in the stomach by pepsin but around 90-95% of protein is digested and absorbed in duodenum and jejunum of the small intestine in the form of amino acids by the action of enzymes trypsin, chymotrypsin and carboxypeptidases.

So the correct option is '90-95%'

Which of the following substances are not absorbed into the lymphatic system?

bio-chemistry digestive system of human absorption of food absorption parts of the digestive system: structure and function

  1. Fatty acids

  2. Glycerol

  3. Fat soluble vitamins

  4. Water soluble vitamins

Show answer
Correct Option: D
Explanation:

Water-soluble vitamins are directly absorbed into the intestine and transported to water as they do not require any emulsification because water is free to move in and out but fat soluble liquids absorb into lymph due to their insolubility in water and they need to emulsify before absorption.

So the correct option is 'Water-soluble vitamins'

Which one of the following is not a step during digestion process?

bio-chemistry food through digestive tract absorption of food absorption parts of the digestive system: structure and function

  1. Ingestion

  2. Digestion

  3. Acid processing

  4. Absorption

  5. Elimination

Show answer
Correct Option: C
Explanation:
  • The chemical breakdown of complex biological molecules into their component parts like lipids into fatty acids, proteins to individual amino acids, carbohydrates into simple sugars.
  • Digestion includes 5 phases :
  1. Ingestion.
  2. Movement.
  3.  Digestion.
  4.  Absorption. 
  5. Further digestion. Hence, the following step not involved during the digestion process is acid processing.
So, the correct answer is 'acid processing'.

Absorption is defined as

bio-chemistry food through digestive tract absorption of food absorption parts of the digestive system: structure and function

  1. elimination of solid waste from the digestive system

  2. breakdown of foods by enzymatic action

  3. passage of nutrients from the gastrointestinal tract into the blood stream

  4. mechanical breakdown of fat

Show answer
Correct Option: C
Explanation:

  • Absorption is the process by which the products of digestion are absorbed by the blood to be supplied to the rest of the body. 
  • During absorption, the digested products are transported into the blood or lymph through the mucous membrane. Hence, Absorption is defined as the passage of nutrients from the gastrointestinal tract into the bloodstream.
So, the correct answer is 'passage of nutrients from the gastrointestinal tract into the bloodstream'.

Most of the absorption of the products of digestion takes place in humans across the

bio-chemistry food through digestive tract absorption of food absorption parts of the digestive system: structure and function

  1. smooth wall of the large intestine

  2. fingerlike villi of the small intestine

  3. convoluted walls of the stomach

  4. squamous epithelium of the oesophagus

Show answer
Correct Option: B
Explanation:
  • The innermost layer lining the lumen of the alimentary canal is the mucosa. This layer forms irregular folds (rugae) in the stomach and small finger-like foldings called villi in the small intestine. 
  • The cells lining the villi produce numerous microscopic projections called microvilli giving a brush border appearance. These modifications increase the surface area enormously. 
  • Villi are supplied with a network of capillaries and a large lymph vessel called the lacteal. Hence, Most of the absorption of the products of digestion takes place in humans across the fingerlike villi of the small intestine
So, the correct answer is 'fingerlike villi of the small intestine'.

$30\%$ starch is hydrolysed in Buccal cavity by which of the following enzymes?

bio-chemistry digestive system of human absorption of food absorption parts of the digestive system: structure and function

  1. Pancreatic $\alpha$ -amylase

  2. Lipase

  3. Maltase

  4. Salivary amylase

Show answer
Correct Option: D
Explanation:

Salivary glands in your mouth (Buccal cavity) make salivary amylase, which begins the digestive process by breaking down starch when you chew your food, converting it into maltose, a smaller carbohydrate.

So the correct option is D, salivary amylase.

Which of the following stimulates the secretion of gastric juice?

bio-chemistry digestion absorption of food absorption parts of the digestive system: structure and function

  1. Gastrin

  2. Enterogastrone

  3. Secretin

  4. Hepatocrinin

Show answer
Correct Option: A
Explanation:

Gastrin is a peptide hormone, that stimulates secretion of gastric acid ($HCl$) by the parietal cells of the stomach and aids in gastric motility. It is released by G cells in the pyloric antrum of the stomach, duodenum and the pancreas.

The gastrointestinal hormone, which stimulates insulin secretion is 

bio-chemistry digestion absorption of food absorption parts of the digestive system: structure and function

  1. Gastrin

  2. CCK

  3. Secretin

  4. GIP

Show answer
Correct Option: D
Explanation:

Gastric inhibitory polypeptide (GIP), also known as the glucose-dependent insulinotropic peptide. The function of GIP is to induce insulin secretion, which is stimulated primarily by hyper osmolarity of glucose in the duodenum.

Secretion of gastric juice is controlled by

bio-chemistry digestion absorption of food absorption parts of the digestive system: structure and function

  1. Gastrin

  2. Cholecystokinin

  3. Enterogastrone

  4. None of the above

Show answer
Correct Option: A
Explanation:

As food enters the confined space of the stomach, it starts applying pressure to the stomach wall distending it a bit. This distention causes the stomach to release gastrin, which stimulates the gastric glands to secrete more gastric juice.

Gastric juice is secreted under the influence of hormone

bio-chemistry digestion absorption of food absorption parts of the digestive system: structure and function

  1. Renin

  2. Enterogastrone

  3. Enterocrinin

  4. Gastrin

Show answer
Correct Option: D