Cell Membranes and Soap Lab

Biology Club Material

Cell Membrane StructureFluid Mosaic Model:

Phospholipid Bilayer- Amphipathic: have both

hydrophilic/phobic regions

Proteins- Integral: penetrate interior- Peripheral: not embedded

Also, carbohydrates function in helping w/cell-cell recognition (glycolipids/proteins)

Has selective permeability!

Functions of Membrane Proteins

Tonicity= ability of a surrounding solution to cause a cell to lose/gain water

Isotonic- Same concentration: no NET movement- plants: flaccid

Hypertonic- higher solute concentration: water flows

OUT of cell- plants: plasmolyzed

Hypotonic- lower solute concentration: water flows

INTO cell- plants: turgid (normal)

Passive Transport

Substances diffuse down (follow) the concentration gradient

Osmosis: water diffuses from lower solute conc --> higher solute conc

Channel & carrier proteins

Active Transport

Energy expended to pump solute against gradient

Carrier proteins only

Membrane potential/electrochemical gradient utilized

Cotransport also

Bulk TransportExocytosis: vesicles move particles OUT of cell

Endocytosis: vesicles take particles INTO cell

- Phagocytosis- Pinocytosis- Receptor-mediated

Soap Lab Materials:

● 80g sodium hydroxide

● 100g coconut oil

● 500g olive oil (for 6 bars of soap)

● 200 mL distilled water

● Additives

● Spoons/stir rods

● Beakers

● Soap mold

● Large vessel

SOAP TIME https://youtu.be/uMBeXHnWhsE

1. Put 200 mL of water into a beaker. Add the 80g of sodium hydroxide and

stir until dissolved. The solution will become hot.

2. Melt the 100g of coconut oil (can be done with a microwave/hot plate)

and combine with the 500-600g of olive oil in a large vessel.

3. Add the sodium hydroxide. Stir the mixture until it is opaque and

thickened.

4. Add the soap to small beakers and mix any additives in.

5. Pour soap mixtures into a mold.

6. Let soap sit for 4-6 weeks for the sodium hydroxide to neutralize.