Buffered Isotonic Solutions and Osmosis

Study Notes

Osmosis and Red Blood Cells

The semipermeable membrane in osmosis allows the passage of water molecules while restricting the movement of larger molecules like solutes.
Suspending red blood cells in a hypertonic solution causes water to move out of the cells, leading to crenation (shrinking) due to the higher solute concentration outside..
Hemolysis is the term for red blood cells bursting when placed in a hypotonic solution.
An isotonic solution has the same solute concentration as the cells it surrounds, resulting in no net movement of water and maintaining cell shape.
When blood is mixed with a hypotonic solution, water moves into the red blood cells, potentially causing them to swell and burst (hemolysis) due to the higher water concentration outside.
A 0.9% NaCl solution is isotonic with blood.
A 2.0% boric acid solution is considered iso-osmotic with blood because it exerts the same osmotic pressure as blood, even though it doesn't have the same solute concentration.
Despite being iso-osmotic, a 2.0% boric acid solution can still cause crenation of red blood cells because it can penetrate the cell membrane, causing a shift in the osmotic balance.
A 0.8% urea solution is not isotonic with blood because urea can readily pass through the cell membrane, leading to a change in the osmotic balance and potentially cell swelling.
A true semipermeable membrane allows the passage of water but not solutes.
Mucous lining of the eye acts as a true semipermeable membrane to boric acid in solution because it restricts the passage of boric acid while allowing water to pass through.
Red blood cell membrane is not a perfect semipermeable membrane because it allows some solutes to pass through, like urea, while restricting others. This makes it selectively permeable.

Description

This quiz covers the concept of osmosis, isotonic solutions, and their relation to semipermeable membranes. It also explores the effects of mixing blood with sodium chloride solutions of varying tonicity.