The Life of the Cell

Chapter 3

Types of Movements1. Diffusion and passive transport

2. Active Transport

3. Phagocytosis & Exocytosis

4. Osmosis

1.

solution

Passive Transport

Nucleus

[Low]

[High]

Note: Solutes move

2. Active Transport: may be ions (e.g. Na+, K+ or other molecules

like glucose).

Requires Energy

Requires a Transporter

Exocytosis Endocytosis and Phagocytosis3.

Movement of large molecules: requires energy

also

http://www.macroevolution.net/images/exocytosis-stanford-sea-urchin.gif

4. Osmosis is :

the movement of WATER from a region of HIGHER WATER

concentration to region of LOWER WATER concentration

across a semi-permeable membrane.

Now: A real life example of how osmosis is important to the human red blood cells.

It is helpful to understand the term of “osmolarity”.

Osmolarity (FYI)

Osmolarity is the measure of solute concentration, defined as the number of osmoles(Osm) of solute per liter(L) of solution (osmol/L or Osm/L).

1 mol/L NaCl corresponds to an osmolarity of 2 osmol/L each mole of NaCl becomes two osmoles in solution, one mole of Na+ and one mole of Cl-.

Similarly, a solution of 1 mol/L CaCl2, gives a solution of 3 osmol/L (Ca2+ and 2 Cl-).

What happens to the shapes of the RBC?

Crenation SwellingNo change

600 mOsm 300 mOsm 200 mOsm

100 200 300 400 500

milliosmosmoles

Red Blood Cells and the affect of Tonicity

We will next discuss our digestive system