Membrane structure

Topic 1.3

Essential idea: The structure of biological membranes makes them fluid and dynamic.

Understandings

1.3.U1 Phospholipids form bilayers in water due to the amphipathic properties of phospholipid molecules.

1.3.U2 Membrane proteins are diverse in terms of structure, position in the membrane and function.

1.3.U3 Cholesterol is a component of animal cell membranes.

Membrane Structure

The the figure below shows the structure of the plasma membrane including phospholipid bilayer, cholesterol, glycoproteins, and integral and peripheral proteins. The term plasma membrane, not the cell surface membrane, is used for the membrane surrounding the cytoplasm. Integral proteins are embedded in the phospholipid bilayer, whereas peripheral proteins are attached to a surface.

Applications

1.3.A1 Cholesterol in mammalian membranes reduces membrane fluidity and permeability to some solutes.

Skills

1.3.S1 Drawing of the fluid mosaic model

The the figure below shows the structure of the plasma membrane including phospholipid bilayer, cholesterol, glycoproteins, and integral and peripheral proteins. The term plasma membrane, not the cell surface membrane, is used for the membrane surrounding the cytoplasm. Integral proteins are embedded in the phospholipid bilayer, whereas peripheral proteins are attached to a surface.

1.3.S2 Analysis of evidence from electron microscopy that led to the proposal of the Daveson-Danielli model

1.3.S3 Analysis of the falsification of the Davson-Danielli model that led to the Singer-Nicolson model.

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