BIOLOGY 2B03 Lecture Notes - Lecture 3: Aquaporin, Osmium Tetroxide, Peripheral Membrane Protein
1 Sep 2020
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Document Summary
Biomembranes define boundaries in a cell by separating the interior from the exterior = create a unique internal environment. Biomembranes can also define internal microenvironments by surrounding organelles. Are selectively permeable --> very few molecules can freely move through. Transport channels can move molecules in and out of a compartment to establish/maintain molecular differences. Hold proteins that can mediate cell-to-cell interactions including receptors and adhesion proteins. Flexibility and dynamics of membrane allow it to change shape without breaking so that the cell can reproduce through cell division. Cytosolic = faces the cytosol inside (part of plasma membrane) Exoplasmic = faces outside into exterior (part of plasma membrane) Lumenal = faces the interior of the organelle (part of organelle membrane) Intermembrane space = space between 2 possible membranes (like mitochondria) Tem images stained with osmium tetroxide (binds to polar groups) revealed two parallel lines on the cell surface --> indicating a bilayer.
