What is the middle lamella between plant cells made of?

The chemical substance most abundantly present in the middle lamella is

Plasmodesmata are

The strength and rigidity of a cell wall is due to the substance known as:

$RBC$ and a plant cell (with thick cell wall) are placed in distilled water. The solute concentration is the same in both the cells. What changes would be observed in them?

Yeast cell wall is rich in