BIOL 1F90 Lecture Notes - Lecture 3: Electrochemical Gradient, Turgor Pressure, Pinocytosis
18 Oct 2016
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Document Summary
The cell membrane holds the contents of a cell in one place so that the chemistry of life can occur. Plasma membrane (phospholipid bilayer): bio-membrane that separates the internal contents of a cell from its external environment. Regulates the traffic of substances into and out of the cell. Selective uptake and export of ions and molecules. Production of energy intermediates, such as atp and nadph. Adhesion of cells to one another and to the extracellular matrix. All biological membranes consist of two layers of lipids, with the most abundant lipids being phospholipids. Membranes always contain proteins and most also have carbohydrates attached to lipids and proteins: = glycolipids and glycoproteins. Phospholipids are amphipathic: hydrophobic tails form the interior of the membrane and hydrophilic heads are on both exterior surfaces, hydrophobic interior makes it difficult for hydrophilic molecules to move across the membrane.
