Describe the structures and functions of the cell wall, cell membrane, and outer membrane.
Cell Wall – ultimately provides a cell its structure, shape, and protection from osmotic forces
Cell walls are mostly composed of peptidoglycan, which is made of chains of the alternating sugar molecules, N-acetylglucosamine and N-acetylmuramic acid. These chains of sugar molecules are attached to one another with the help of other chains composed of four amino acids called tetrapeptides.
There are two types of cell walls:
-Gram-Positive
-Gram-Negative
* Plants, most bacteria, fungi, most algae, and some archaea have cell walls Protozoans and animals do not have a cell wall.
Cell Membrane – this selective permeable membrane allows a cell to take in nutrients and excrete waste out of the cell
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A phospholipid is a combination of a hydrophilic phosphate head (loves water) and two hydrophobic hydrocarbon tails. The phospholipid bilayer gives the membrane its selectiveness because large molecules cannot pass through it ions and molecules with an electrical charge are repelled by it and hydrophilic substances cannot easily cross its hydrophobic interior. These substances have no choice but to go through the membrane’s integral proteins that act as recognition proteins, enzymes, receptors, carriers, or channels. There are two forms of travel through a cell’s membrane:
- Passive Transport- requires no exerted energy; energy comes from the cell’s electrochemical