Carrier ions like Na+ facilitate the absorption of substances like:[2010]a)amino acids and glucoseb)glucose and fatty acidsc)fatty acids and glycerold)fructose and some amino acidsCorrect answer is option 'A'. Can you explain this answer?

Question

Answer

Absorption of glucose takes place with the help of a carrier protein that carries out the co-transport of glucose along with two sodium ions. Absorption of amino acids also takes place by a similar mechanism with the help of a sodium-dependent co-transporter. Absorption of fructose occurs by facilitated diffusion, and fatty acids and glycerol by a simple diffusion mechanism. So, the correct option is 'Amino acids and glucose'.

Answer

Glucose and amino acids are co-transported along with sodium ions in the intestinal epithelium. The Na/Glucose cotransporter (SGLT 1) facilitates glucose-coupled sodium absorption while amino acid-coupled sodium absorption occurs through the epithelial cells with the help of Na/amino acid cotransporters.

Answer

Carrier ions like Na facilitate the absorption of substances like amino acids and glucose. This process occurs primarily in the small intestine and is essential for the body to obtain nutrients from the food we consume. Let's explore this topic in more detail:

1. Introduction:
- Carrier ions play a crucial role in facilitating the transport of various substances across cell membranes.
- Sodium ions (Na+) are one such carrier ion that aids in the absorption of certain nutrients.

2. Absorption in the Small Intestine:
- The small intestine is responsible for the majority of nutrient absorption in the digestive system.
- The inner lining of the small intestine contains microscopic finger-like projections called villi, which increase the surface area for absorption.

3. Sodium-Glucose Co-Transport:
- The absorption of glucose in the small intestine is facilitated by a process called sodium-glucose co-transport.
- In this process, sodium ions actively transport glucose molecules from the intestinal lumen into the epithelial cells lining the small intestine.
- The carrier protein responsible for this co-transport is known as SGLT1 (sodium-glucose co-transporter 1).
- Sodium ions move down their concentration gradient, simultaneously carrying glucose molecules into the cells against their concentration gradient.
- Once inside the epithelial cells, glucose can then passively diffuse into the bloodstream.

4. Sodium-Amino Acid Co-Transport:
- Amino acids, the building blocks of proteins, are also absorbed in the small intestine with the help of sodium ions.
- Similarly to glucose, the transport of amino acids involves sodium co-transporters located on the apical surface of the epithelial cells.
- These carrier proteins actively transport both sodium ions and specific amino acids into the cells.
- Once inside the cells, amino acids can be further processed and transported across the basolateral membrane into the bloodstream.

5. Significance:
- The facilitation of glucose and amino acid absorption by carrier ions like sodium is crucial for providing the body with necessary nutrients.
- Glucose is an essential energy source for cells, while amino acids are used for protein synthesis and various metabolic processes.
- Without the involvement of carrier ions, the absorption of these substances would be significantly impaired, leading to nutrient deficiencies and impaired bodily functions.

In conclusion, carrier ions like sodium (Na+) play a vital role in facilitating the absorption of substances like amino acids and glucose in the small intestine. This process is essential for providing the body with necessary nutrients and maintaining proper bodily functions.

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