Content Objective: Students will be able to explain the how the structure of the phospholipids and proteins in a membrane help with the membrane's function.
Language Objective: Explain the structure of the membranes and the roles the various compounds play.
Book Reference:
Syllabus Details:
B1.1.12—Formation of phospholipid bilayers as a consequence of the hydrophobic and hydrophilic regions - “Students should use and understand the term “amphipathic”.
B1.1.13—Ability of non-polar steroids to pass through the phospholipid bilayer - "Include oestradiol and testosterone as examples. Students should be able to identify compounds as steroids from molecular diagrams."
B2.1.1 - Lipid bilayers as the basis of cell membranes Phospholipids and other amphipathic lipids naturally form continuous sheet-like bilayers in water.
B2.1.2 - Lipid bilayers as barriers - "Students should understand that the hydrophobic hydrocarbon chains that form the core of a membrane have low permeability to large molecules and hydrophilic particles, including ions and polar molecules, so membranes function as effective barriers between aqueous solutions."
B2.1.4 - Integral and peripheral proteins in membranes - "Emphasize that membrane proteins have diverse structures, locations and functions. Integral proteins are embedded in one or both of the lipid layers of a membrane. Peripheral proteins are attached to one or other surface of the bilayer."
B2.1.10 - Fluid mosaic model of membrane structure - "Students should be able to draw a two-dimensional representation of the model and include peripheral and integral proteins, glycoproteins, phospholipids and cholesterol. Indicate hydrophobic and hydrophilic regions."
B2.1.11 HL - Relationships between fatty acid composition of lipid bilayers and their fluidity - "Unsaturated fatty acids in lipid bilayers have lower melting points, so membranes are fluid and therefore flexible at temperatures experienced by a cell. Saturated fatty acids have higher melting points and make membranes stronger at higher temperatures. Students should be familiar with an example of adaptations in membrane composition in relation to habitat."
B2.1.12 HL - Cholesterol and membrane fluidity in animal cells - "Students should understand the position of cholesterol molecules in membranes and also that cholesterol acts as a modulator (adjustor) of membrane fluidity, stabilizing membranes at higher temperatures and preventing stiffening at lower temperatures."
Activity 1 - Notes on the Cell Membranes
Activity 2 - Membranes Concept Maps
Task: Your task it to create a concept map that include the following key vocabulary:
Amphipathic, Hydrophilic, Hydrophobic, Non-polar, Steroids, Oestradiol,Testosterone, Continuous Sheet-like Bilayers, Low Permeability, Integral Proteins, Peripheral Proteins, Fluid Mosaic Model, Glycoproteins
Additional HL: Saturated Fatty Acids, Unsaturated Fatty Acids, Cholesterol
A. Strengthen Your Skills
B. Expand Your Knowledge