Question

Describe how a selectively permeable membrane is involved in osmosis. Include the role that the solute concentration plays in the direction of water movement. Now think about how this process may differ between plant and animal cells. For instance, how might cell walls disrupt the role of solute concentration and cause one to refute a hypothesis for the direction of water movement based on water concentration alone?

Answer 1

Answer:

Solute size and charge is very essential in letting it pass through any selectively permeable membrane

Also cell wall in plant cell  is semi permeable layer and plasma membrane in animal cell is selectively permeable

Explanation:

A selectively permeable membrane is the one that allows only selected particles, ions or solute to pass through it. Thus, solute suitability is essential for selective permeability.  

For instance diffusion of oxygen and carbon dioxide through the cell membrane is an example of selective permeability. Other than O2 and CO2, no other substance is allowed to pass through the membrane.  

In plant cell, a cell wall itself acts as a semi permeable membrane thereby allowing passage of uncharged molecules and proteins through it on the basis of size. While on the other hand plasma membrane is selectively permeable and allows hydrophobic small molecules to pass through it but restricts the passage of ions and large polar molecules. A cell wall restricts the flow of water from region of higher concentration to regions of lower concentration. Thereby protecting the plant cell from bursting, while an animal cell burst due to inflow of excess water as plasma membrane is incapable of restricting  water flow.