Lecture 1 Historical observations of the cell membrane

Lecture 1 Historical observations of the cell membrane -...

Info iconThis preview shows pages 1–6. Sign up to view the full content.

View Full Document Right Arrow Icon
Introductory Physiology PCB 4713C Dr. G. A. Ahearn Lecture 1: Historical observations of the cell membrane Reading assignment: Singer, S. J. and Nicolson, G. L. (1972) The fluid mosaic model of the structure of cell membranes, Science, Vol. 175: pp. 720-731.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
1. Lipid solubility: In 1895 Overton showed that fatty substances penetrated cell membranes faster than non-fatty materials. He suggested than membranes were composed of fatty substances that allowed similar molecules to pass through, but excluded water soluble chemicals. 2. Thickness of lipid layer: In 1925 Gorter and Grendel extracted total lipid from red blood cells and spread as a monolayer on water. Compared surface area of total lipid with calculated area knowing number of cells and the diameter of each. Found twice the extracted surface area than calculated area – lipid must be arranged in a double layer in cell membranes.
Background image of page 2
First model of the cell membrane (1925) Hydrophilic part of lipid Hydrophobic part of lipid Outside of cell Inside of cell Membrane H 2 O H 2 O
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Historical observations of the cell membrane 3. Electrical resistance : Between 1910 and 1937 scientists passed electrical current through cell membranes. Membra resisted the flow of current more than would an ion solution a membrane made only of proteins. Conclusion was membr was only made of lipid. 4. Surface tension : In 1930s it was found that membranes onl possessed 1% of the surface tension of a fully lipid membra It was known that proteins can adsorb to surfaces and lowe the surface tension as a result. Conclusion: Membranes we composed of a double lipid layer with an adsorbed protein c on both sides.
Background image of page 4
membrane Around 1930s Hydrophilic part of lipid Hydrophobic part of lipid Outside of cell Inside of cell Membrane H 2 O H 2 O Protein coat Protein coat
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 6
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 20

Lecture 1 Historical observations of the cell membrane -...

This preview shows document pages 1 - 6. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online