Biology/phospholipids
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Question
why do the phospholipids surrounding the cell form a bilayer?
Hi Thomas: Thanks for your question.
Phospholipids are amphipathic. That means they have a hydrophobic (water hating) end and a hydrophilic (water loving) end. The hydrophobic ends are the long chain lipids that sort themselves away from the water, on the inside of the membrane. Remember, oil and water don't mix.
The hydrophilic ends are the charged phosphate groups that sort themselves into the water phase. So the lipids point inwards, and the phosphates point outwards.
The mixture spontaneously forms micelles (small balls) with the phosphate on the outside of the double membrane, close to the water and the lipid on the inside of the double membrane, close to each other.
Here's a website with a picture:
http://en.wikipedia.org/wiki/Cell_membrane
Hope this helps. Please write back if you have more questions.
FM Rollwagen, PhD
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Answers by Expert:
Florence M Rollwagen
Expertise
I can answer questions in biology, microbiology and immunology on the undergraduate or graduate level. I can also address medical and health concerns regarding alternative medicine, autoimmune diseases (lupus, MS) liver disease and intestinal problems.
Experience
I have over 20 years experience in research and teaching at the medical/graduate level, and 5 years teaching college biology and microbiology. My expertise is in microbiology and immunology, specifically the biology of cytokines and soluble immune response modifiers. I also carried out original research in blood substitutes and shock/trauma.
Organizations
American Association of Immunologists (AAI)
American Association for the Advancement of Science (AAAS)
Publications
Journal of Experimental Medicine, Journal of Immunology, Cytokine, Shock, Experimental Hematology
Education/Credentials
BS biology 1966
MS biology 1968
PhD immunology 1979
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