Fastest absorbing sugar in the intestine
**Core Concept**
The question is testing the ability to identify the fastest absorbing sugar in the intestine, which is an essential concept in understanding the pathophysiology of carbohydrate metabolism and the treatment of diabetic emergencies.
**Why the Correct Answer is Right**
Glucose is the fastest absorbing sugar in the intestine due to its unique molecular structure, which allows it to be rapidly transported across the intestinal epithelial cells via the sodium-glucose cotransporter (SGLT1). This process is facilitated by the presence of a glucose molecule on the same side of the transporter as the sodium ion, enabling a high-affinity binding and rapid uptake of glucose into the bloodstream.
**Why Each Wrong Option is Incorrect**
* **Option A:** Fructose is absorbed in the intestine via facilitated diffusion, but it is slower than glucose due to its lower affinity for the glucose transporter.
* **Option B:** Lactose is a disaccharide composed of glucose and galactose molecules, and its absorption is slower than glucose due to the need for hydrolysis by lactase enzyme before absorption.
* **Option C:** Sucrose is a disaccharide composed of glucose and fructose molecules, and its absorption is slower than glucose due to the need for hydrolysis by sucrase enzyme before absorption.
**Clinical Pearl / High-Yield Fact**
Glucose absorption is a critical factor in the management of diabetic emergencies, such as hypoglycemia and hyperglycemia, and understanding the fastest absorbing sugar in the intestine is essential for effective treatment.
**Correct Answer: B. Fructose is absorbed in the intestine via facilitated diffusion, but it is slower than glucose due to its lower affinity for the glucose transporter.**