Here's why:
* Dialysis tubing is a semi-permeable membrane. It allows small molecules like water, salts, and simple sugars to pass through, but it blocks larger molecules.
* Starch molecules are complex carbohydrates made up of many glucose units linked together. They are significantly larger than the pores in the dialysis tubing.
Think of it like a sieve:
* The dialysis tubing is like a sieve with small holes.
* Small molecules (like water) can pass through the holes easily.
* Large molecules (like starch) are too big to fit through the holes.
This principle is used in various applications, including:
* Kidney dialysis: Dialysis tubing is used to remove waste products and excess fluids from the blood of patients with kidney failure.
* Food processing: Dialysis tubing is used to separate components of food mixtures, such as separating whey from cheese.
* Laboratory experiments: Dialysis tubing is used to study the movement of molecules across membranes.
