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Biology notes
The cell membrane:
The cell membrane helps a cell to maintain homeostasis by controlling the
movement of substances across the membrane
Cells need: nutrients, vitamins
Cells get rid of: waste, CO2
Homeostasis: keep constant conditions
( ex: the cell wants the right amount of oxygen otherwise the cell won't be able to
function)
The cell membrane is mostly made up of molecules called phospholipids
(print a picture off of google images of a single phospholipid) circular head with 2
tails
Phospholipids have heads which are hydrophilic (attracted to water)
Phospholipids have lipid tails which are hydrophobic (repelled by water)
( ex: wax on cars or rainex on windshields to repel water)
Another name for lipids are fats
Fats, wax, Oil, are hydrophobic (things that are repelled by water)
The cell membrane also has proteins. These proteins include cell surface
markers, enzymes, receptor proteins, and transport proteins