Chapter 2 section 2.2 Pages 81-86 Membranes Chapter 2 section 2.2 Pages 81-86

Membranes In a cell, what is the purpose of a membrane?

Fluid mosaic model Most membranes are made up of a combination of lipids, proteins and carbohydrates Membranes aren’t rigid but instead the parts are free to move around Semi-permeable

Lipids in the membrane Dominant lipid is the phospholipid Chemical properties of head? tail?

Fluidity of membrane How fluid a membrane is depends on: Temperature Composition (types) of lipids Temperature: What happens at high temperatures? Low temperatures?

Fluidity of membrane How fluid a membrane is depends on: Temperature Composition (types) of lipids Composition: Saturated vs unsaturated What does each of these types of lipids do to the membrane?

Fluidity of membrane How fluid a membrane is depends on: Temperature Composition (types) of lipids Composition: Cholesterol? What does it have to do with anything?

Membrane proteins Roles: Transport Moving substances across the membrane Specificity? Examples?

Membrane proteins Roles: Enzymes Catalyze reactions Examples?

Membrane proteins Roles: Attachment and recognition Some act as points of attachment i.e. a cell’s cytoskeleton is anchored to membrane and gives shape and rigidity Recognition Allows certain components to recognize certain cells WBC recognize a cell as “self” based on membrane proteins present

Membrane proteins Roles: Signaling Are recognized and bound by certain chemicals like hormones Pass this “signal” into the cell, setting of a cascade of events

Membrane proteins Types:

Membrane proteins Types: Integral membrane proteins Where are they found? Are they hydrophobic, hydrophilic or both? What does transmembrane mean? Examples?

Membrane proteins Types: Peripheral membrane proteins Where are they found? Are they hydrophobic, hydrophilic or both? Examples?

Membrane carbohydrates Glycolipids: Glycoproteins: Roles: