Test: Absorption of Nutrients (Old NCERT) - JAMB MCQ

After digestion, most of the monosaccharides are absorbed into the body via active transport using sodium ions. Fructose is absorbed via facilitated diffusion. Amino acids are absorbed via secondary active transport using sodium ions. Chylomicrons cannot enter blood capillaries and hence enter lacteals. Only 5% of starch is hydrolyzed in the mouth. Proenzyme pepsinogen is secreted by chief cells in the stomach

So, the correct answer is 'Fructose and amino acids are absorbed through intestinal mucosa with the help of carrier ions like Na⁺'.

The human small inteestine is the longest (6.25m) part of alimentary canal. Villi present in the small intestine increase it surface area for absorption as most of the absorption occurs in small intestine.

Most ions are actively absorbed along the length of small intestine. The absorption of Na⁺ is coupled with absorption of glucose and amino acids. Glucose and galactose are taken into the enterocyte by cotransport with sodium using the same transporter. Fructose enters the cell from the intestinal lumen via facilitated diffusion through another transporter. Fatty acids are combined with proteins within the cells and resulting chylomicrons are extruded. They enter lacteals and are transported to the circulation via lymph. 

The chief cells of gastric glands secrete a small amount of gastric lipase that contributes little to digestion of fat.

• The breakdown of most of the biomacromolecules happens in the duodenum part of the small intestine.
• Whereas the simple substances are being absorbed by the jejunum and the ileum region of the small intestine.
• The large intestine is responsible for the absorption of the food after its being completely digested in the small intestine.
• Whereas the undigested and unabsorbed food materials are passed through the large intestine then to the rectum and finally it is excreted as excreta through the anus.

Hence, option (C) is a false statement out of the above statements.

In the mouth certain drugs are absorbed. In the large intestine, water, some minerals and drugs are absorbed

The correct statement about chylomicrons is:
(i) Chylomicrons are produced in the epithelial cells of the small intestine.
The incorrect statements about chylomicrons are:
(ii) Chylomicrons contain triglycerides, cholesterol, and phospholipids.
(iii) Chylomicrons are protein-coated small vesicles.
(iv) Chylomicrons are released from the epithelial cell into lacteals.
Therefore, the incorrect statements are (ii), (iii), and (iv).
Explanation:
Chylomicrons are large lipoprotein particles that are responsible for transporting dietary fats from the small intestine to various tissues in the body. Here is a detailed explanation of each statement:
(i) Chylomicrons are produced in the epithelial cells of the small intestine.
- This statement is correct. Chylomicrons are synthesized in the intestinal epithelial cells, specifically the enterocytes, after the absorption of dietary fats.
(ii) Chylomicrons contain triglycerides, cholesterol, and phospholipids.
- This statement is incorrect. Chylomicrons primarily consist of triglycerides, phospholipids, and some cholesterol. They also contain small amounts of specialized proteins called apolipoproteins.
(iii) Chylomicrons are protein-coated small vesicles.
- This statement is incorrect. Chylomicrons are not small vesicles. They are large particles ranging in size from 75-1200 nm. While they do have a protein coating in the form of apolipoproteins, they are not considered vesicles.
(iv) Chylomicrons are released from the epithelial cell into lacteals.
- This statement is incorrect. Chylomicrons are released from the intestinal epithelial cells into the lymphatic system through specialized lymphatic vessels called lacteals, not directly into lacteals.
Therefore, the correct answer is option D: None of these.

lleo-caecal valve is present at the junction of small intestine and large intestine. The ileo-caecal valve normally remains closed, opens briefly to let the contents of small intestine exit and closes again to prevent any backflow of waste materials from the large intestine into small intestine

Fructose is generally absorbed by facilitated trasnport. The digestive wastes, solidified into coherent faeces in the rectum initiate a neutral reflex causing an urge or desire for its removal.

Minerals are transported through xylem along the ascending stream of water. Phloem is used for the translocation of solutes and sometimes organic nitrogen compounds. Phloem exhibits both upward and downward movement of food along with the movement of water in the adjacent cells.