Problem 40 - A Complete Resource Book in Chemistry for JEE Main

Question

Dialysis can separate which of the following in addition to the glucose from the human blood? (a) fructose (b) starch (c) proteins (d) sucrose

Step-by-Step Solution

Answer

Fructose (option a) can be separated by dialysis.

Step 1: Understanding Dialysis

Dialysis is a process where small molecules and ions diffuse through a semi-permeable membrane, separating them from larger molecules that cannot pass through the membrane.

Step 2: Analyzing Given Options

Let's examine each option: (a) Fructose is a small molecule similar to glucose, (b) Starch is a large polysaccharide, (c) Proteins are large, complex molecules, and (d) Sucrose is a disaccharide composed of glucose and fructose.

Step 3: Determining Potential Dialysis Candidates

Small molecules can pass through the dialysis membrane, while large molecules cannot. Therefore, fructose (a small molecule) and sucrose (a disaccharide but still smaller than starch and proteins) can potentially be separated by dialysis.

Step 4: Final Decision

Since both glucose and fructose are monosaccharides with similar molecule sizes, fructose (option a) can be separated from the blood by dialysis, while larger molecules like proteins, starch, and even sucrose are typically too large or complex to pass through the dialysis membrane efficiently.

Key Concepts

Semi-permeable membrane

A semi-permeable membrane is crucial in processes like dialysis. It acts as a selective barrier, allowing only certain molecules to pass. This membrane is analogous to a sieve, filtering molecules based on size.
In the case of dialysis, the semi-permeable membrane helps separate small molecules, such as glucose, by enabling them to diffuse through the tiny pores, while larger molecules, such as proteins, are blocked.
This property is beneficial in medical procedures where undesired substances must be removed from the blood. The selectivity ensures only specific, smaller molecules like waste products are filtered out, maintaining the larger essential components in circulation.

Molecular separation

Molecular separation is the principle behind dialysis, impacting its effectiveness in filtering blood. This process relies on differences in molecular size to separate substances.
Dialysis uses a semi-permeable membrane to exploit these size differences, where:

• Small molecules like glucose pass through easily.
• Larger molecules, such as proteins or starch, are too large to pass through and remain confined to one side of the membrane.

This principle is fundamental in dialysis and other separation technologies. It ensures that only target molecules are removed, allowing accurate and purposeful filtering of compounds based on their molecular dimensions.

Glucose

Glucose is a simple sugar, classified as a monosaccharide, and plays a vital role in providing energy to cells. Its small size makes it ideal for separation through dialysis.
During dialysis, glucose molecules can easily traverse the semi-permeable membrane due to their size. This capability makes glucose a primary target in dialysis processes, as it can be efficiently and selectively separated from larger macromolecules like proteins or polysaccharides.
Understanding glucose's characteristics is essential when considering its separation from blood in medical treatments. Its small molecular size ensures it moves efficiently across the semi-permeable membrane, highlighting its significance in medical and biochemical applications.