Notes

The cell membrane is a thin semi-permeable membrane that surrounds the cytoplasm of a cell, enclosing its contents. Its function is to protect the integrity of the interior of the cell by allowing certain substances into the cell, while keeping other substances out. It also serves as a base of attachment for the cytoskeleton in some organisms and the cell wall in others. Thus the cell membrane also serves to help support the cell and help maintain its shape. The cell membrane is primarily composed of a mix of proteins and lipids. While lipids help to give membranes their flexibility, proteins monitor and maintain the cell's chemical climate and assist in the transfer of molecules across the membrane.Phospholipids are a major component of cell membranes. They form a lipid bilayer in which their hydrophillic (attracted to water) head areas spontaneously arrange to face the aqueous cytosol and the extracellular fluid, while their hydrophobic (repelled by What is a Cell Wall?

All living things are composed of cells. They are the building blocks of all life. Cells come in many different shapes and have different functions. Plant and animal cells are different too. The main difference between plant and animal cells is that plant cells have a cell wall on the outer layer, whereas animal cells only have a cell membrane.

Function

A plant cell wall has many important jobs. The main two jobs it has are to provide protection and support for the plant. In fact, it is the cell wall that gives the plant its actual shape. It acts as a gate keeper, determining what can come in and out of the cell, in order to keep the cell protected. It is kind of like the outside bricks of a castle, only, as you will learn as you read on, there are holes throughout this castle. Those holes do make the cell vulnerable, but they are important to the function of the cell.


A plant cell has a cell wall, whereas an animal cell only has a cell membrane.


water) tail areas face away from the cytosol and extracellular fluid.