Question

The salinity (salt concentration) of blood is approximately 0.9% while the salinity of sea water is approximately 3.5%. Explain, in your own words using terms such as hyper- or hypotonic, osmosis, diffusion, concentration gradient, and so forth, what would happen if a) your blood cells were placed in sea water instead of blood plasma and b) your blood cells were placed in distilled water instead of blood plasma.

a) sea water:

b) distilled water:

Answer 1

Answer:

Background:

Osmosis: Osmosis is the proces of diffusion or movement of water molecules across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration

Hyperosmotic: In this case the osmotic pressure of the extracellular fluid is more than the osmotic pressure inside the cell.

Hypoosmotic: In this case the osmotic pressure in the extracellular fluid is less than the osmotic pressure inside the cell.

Hypotonic:In this case the osmolarity in the extracellular fluid is less than the osmolarity inside the cell and therefore, the water will move from the extracellular fluid to the inside of cell that contains higher amount of solute concentration.

Salt concentration of blood = ~ 0.9%

Salinity of sea water = ~3.5%

a) your blood cells were placed in sea water instead of blood plasma:

The blood cells predominately consists of water. When these are placed in a sea water that contains a lot of salt (3.5%), then the extracellular fluid (sea water in this case) is hypertonic compared to the blood cell.

Therefore the water will move or diffuse from low solute concentration (inside the cell) to high solute concentration (sea water) and the blood cells will shrink in size.

b) your blood cells were placed in distilled water instead of blood plasma.

In this case, the concentration of solute inside the blood cells is more compared to the concentration of the solute in the distilled water. Therefore the blood cells are placed in a hypotonic environment that would facilitate the movement /diffusion of water molecules (through the plasma membrane) from an area of lower solute concentration (distilled water) to an area of higher solute concentration (inside the blood cell) causing the blood cells to swell.