2.8+Cells-structure


The cell is like a little factory, thinking of it like this may help you remember the functions of the organelles.

Video of the organelles of a cell.
media type="youtube" key="k3UXY9U0orA" height="344" width="425"

This website has a lot of useful animations to look at [|scilink] Check out this one of a cell [|Tour of the cell]

[|Cell structure] useful diagrams of plant and animal cells with a useful self test sheet. Click on this [|link]and complete the table like the one attached below, which you can print out, but using the information on the interactive cell models. Good for revision!



** Cell Membrane **

The currently accepted model of the plasma membrane is known as the fluid mosaic model.

 The cell membrane consists of a Phospholipid bilayer (2 sheets of lipids). The hydrophobic tails face inwards, with the polar, hydrophillic heads on the outside. It is embedded with proteins and strengthened with cholesterol molecules. The mobile proteins floating within it are thought to have a number of different functions, including a role in active transport.

This picture shows how the cholesterol is dispersed through the membrane, disturbing the close packing of the phospholipids. This helps keep the membrane more fluid.

Proteins:- > > media type="youtube" key="vh5dhjXzbXc" height="344" width="425" > As revision check out these flashcards and test yourself [|Flashcards] Or try the ones below.media type="custom" key="3806669"
 * some proteins are stuck to the surface membrane
 * Some proteins completely penetrate the phospholipid bilayer. These proteins may control the entry and exit of specific molecules into and out of the cell
 * some proteins may play an important role in immune responses. They identify the cell as belonging to the body and not to that of some invading pathogen