Absorption of amino acids through the intestinal wall requires active transport.
a.All three statements are true.
b.Two of the three statements are true.
c.Only one of the statements is true.
d.None of the statements is true.
The correct answer and explanation is :
The correct answer is: b. Two of the three statements are true.
Explanation:
The absorption of amino acids through the intestinal wall is a crucial part of digestion and nutrient assimilation. The three key points that determine the correct answer are:
- Amino Acid Absorption Mechanism: Amino acids are absorbed in the small intestine primarily through active transport mechanisms. Specific transporter proteins help move amino acids across the intestinal wall using energy, making this statement true.
- Facilitated Diffusion Also Plays a Role: While active transport is the primary mechanism, some amino acids can also be absorbed via facilitated diffusion, which does not require direct energy but relies on concentration gradients. This makes the statement about absorption requiring only active transport partially incorrect, as diffusion also contributes.
- Peptide Transport: Small peptides (dipeptides and tripeptides) can also be absorbed through a separate transport system called PEPT1, which allows them to be taken up and then hydrolyzed into free amino acids inside enterocytes. This means that the statement does not account for peptide transport, making it not entirely correct.
Since two of the three statements about amino acid absorption are true, the best answer is option (b).
