An experiment was set up to determine the movement of molecules through a dialys

Question

An experiment was set up to determine the movement of molecules through a dialysis-tubing bag into water. A dialysis-tubing bag containing 5% lactose and 5% fructose was placed in a beaker of distilled water, as illustrated. After four hours, fructose is detected in the distilled water outside of the dialysis-tubing bag, but lactose is not. What conclusions can be made about the movement of molecules in this experiment?

A. Fructose, being a monosaccharide, diffused through the dialysis bag into the distilled water. However, lactose, being a disaccharide, could not diffuse through the dialysis bag.

B. Fructose was homogenized by lactose, allowing the fructose to diffuse through the dialysis bag and into the distilled water. Lactose is not homogenized, so it could not pass through the dialysis bag.

C. Fructose and lactose are oppositely charged and separated out due to the force of repulsion.

D. Fructose diffused because of the pore specificity of the semipermeable membrane, not because of its concentration gradient.

Explanation / Answer

The correct answer is A

Dialysis tubing bag is semipermeable like cell membarane. Microscopic holes or pores in the tubing bag allows smaller molecules across the bag.

Fructose is a monosaccharide means it is a single smaller molecule that can move across the bag.

Lactose is a disacccharide (glucose + galactose) a larger molecule than fructose so it canot move across the bag.

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