Web view01.06.2014 · : Span the bilayer and allows ions molecules to pass by passive...
2
1.3 Membrane Structure (http://en.wikipedia.org/wiki/Wikipedia:Featured_picture_candidates/ Cell_membrane_(diagrammatic)) Hydrophilic heads of the molecules always appear on the outside of the membrane where water is present, while the hydrophobic tails orientate themselves in a double layer away from the water. The structure is a fluid. Integral proteins are hydrophobic on at least part of their surface and they are therefore embedded in the hydrocarbon chains in the center of the membrane.
Transcript of Web view01.06.2014 · : Span the bilayer and allows ions molecules to pass by passive...
1.3 Membrane Structure
(http://en.wikipedia.org/wiki/Wikipedia:Featured_picture_candidates/Cell_membrane_(diagrammatic))
Hydrophilic heads of the molecules always appear on the outside of the membrane where water is present, while the hydrophobic tails orientate themselves in a double layer away from the water. The structure is a fluid.
Integral proteins are hydrophobic on at least part of their surface and they are therefore embedded in the hydrocarbon chains in the center of the membrane.
Peripheral proteins are hydrophilic on their surface, so are not embedded in the membrane. Most of them are attached to the surface of integral proteins and this attachment is often reversible.
Cholesterol is often present in animal cells and makes the membrane more ridged and make the membrane less permeable to water soluble molecules.
(http://www.mhhe.com/biosci/ap/ap_prep/cem3s1_4.jpg)
Function of the cell membraneRemember ‘PEECH’
Pumps: For actively transporting molecules in or out of the cell.Enzymes: Integral protein with enzymes to carry out metabolism reaction.Electron Carriers: Transport electrons back and forth.Channels: Span the bilayer and allows ions molecules to pass by passive transport — require energy e.g. diffusion & osmosisHormone Binding Site: Special shapes to recognize hormones to which the cell can respond.
