The cell membrane is made mostly of lipids. How can it allow cells to mantain a shield between aqueous enviroments both on the inner and outer of the cell?
2006-09-30 17:44:56 · 4 answers · asked by dundundun 1 in Science & Mathematics ➔ Chemistry
cell membrane is made up of phospholipids. The lipids are hydrophobic so do not let the aqueous substances pass in and out so easily.
2006-09-30 17:58:15 · answer #1 · answered by jo88 2 · 0⤊ 0⤋
Lipids are fatty substances; they cling together and are able to form the cell walls. But, since they can be permeated the cells can exchange material.
According to Wikipedia: http://en.wikipedia.org/wiki/Cell_walls
"A cell wall is a more or less solid layer surrounding a cell. They are found in bacteria, archaea, fungi, plants, and algae. Animals and most other protists have cell membranes without surrounding cell walls. When a cell wall is removed using cell wall degrading enzymes, what is left of the cell and its surrounding plasma membrane is called a protoplast. The cell wall's main purpose is to actually protect the interior from any physical movement that may damage the cell."
According to Wikipedia:
"Lipids are a class of hydrocarbon-containing organic compounds essential for the structure and function of living cells. Lipids are categorized by the fact that they are soluble in nonpolar solvents (such as ether and chloroform) and are relatively insoluble in water. Lipid molecules have these properties because they consist of mainly carbon and hydrogen, with few oxygen-containing functional groups. Some lipids are used for energy storage, others serve as structural components of cellular membranes, and some are important hormones. Although the term lipid is often used as a synonym for fat, the latter is in fact a subgroup of lipids called triglycerides."
So the "good fat" that the body needs is converted to lipids, which are long chain hydrocarbons similar to plastic, only a very thin layer. The lipids are NOT water soluble so when laid out in a structure they are firm enough to hold the contents of the cell inside and prevent material from outside coming in. To get nutrients the cell uses enzymes to open holes in the cell wall and let those nutrients in, and it expels its waste the same way.
2006-09-30 17:56:33 · answer #2 · answered by Dan S 7 · 0⤊ 0⤋
its a membrane and not a liquid, membrane examples r... u can see a layer on top of tea or coffe after it remains at rest for sometime. I think u can relate!
2006-09-30 19:05:14 · answer #3 · answered by mirchi amrita 1 · 0⤊ 0⤋
Lipids are not water friendly, they therefore do not dissolve.
2006-09-30 17:56:54 · answer #4 · answered by ag_iitkgp 7 · 0⤊ 0⤋