Question

During sodium-dependent glucose transport (symport or co-transport), the

• A. Na⁺ is transported passively from the lumen into the gut, glucose is transported against concentration gradient
• B. Na⁺ and glucose both are transported actively into the gut from lumen
• C. Na⁺ and glucose both are transported passively
• D. Na⁺ is transported actively and glucose passively

Answer 1

Answer: (A)

Small amounts of monosaccharides like glucose, amino acids and some of the electrolytes like chloride ions are generally absorbed by simple diffusion. The passage of these substances into the blood depends upon the concentration gradients. However, some of the substances such as fructose and some amino acids are absorbed with the help of the carrier ions like Na⁺. This mechanism is called facilitated transport.