Do NowOne curve represents the

diffusion of glucose through the lipid bilayer, and the other represents

the transport of glucose by facilitated diffusion. Which

curve corresponds to facilitated diffusion?

Explain your reasoning.

Endocytosis

• “Endo-” means in.

• “cyto-” means cell.

• “osis” means process of.

• What does endocytosis mean?

• Endocytosis: the process by which cells take in large amounts of material, by folding in the cell membrane

Endocytosis Example• Pinocytosis:

non-specific endocytosis of small amounts of extracellular fluid.

• Greek: “pino-” = “drinking”

Endocytosis Example • Phagocytosis:

the endocytosis of solid particles such as bacteria, cell debris, or other solids

• Greek: “phago-” = “eating”

Phagocytes

• Phagocytes, such as some types of white blood cells, engulf foreign cells by phagocytosis.

For Protists, Phagocytosis = Eating

Exocytosis

• Exocytosis is the same process as endocytosis, except in reverse.

• The stuff leaving may be:– Proteins released into the ECF– New lipids for expanding the membrane– Membrane proteins– Chemicals for communication, etc. (e.g. dopamine)

Exocytosis

Endo and Exocytosis – quick review

The Sodium / Potassium Pump• The Na+/K+ pump is responsible for

maintaining the electrical charge of a cell– Cells are negative

• Communication, e.g. neurons• Cation uptake

• It is an example of a membrane pump which move specific things into or out of the cell AGAINST THEIR CONCENTRATION GRADIENT.

• Since it requires energy, it is an example of ACTIVE TRANSPORT!

How the Na+/K+ Pump Works

• Don’t forget the animation….

Recap: Active Transport Uses ATP• Endocytosis = cell taking in material by infolding

the membrane.– Pinocytosis = “cell drinking” ECF– Phagocytosis = “cell eating” bacteria, etc.

• Exocytosis = cell exporting materials in bulk.

• Na+/K+ Pump = an example of a membrane pump that moves sodium ions out and potassium ions in AGAINST the concentration gradient. Causes cells to be negatively charged.