3.1

what makes up the cell envelope

• cytoplasmic membrane

• cell wall

• capsule

Phospholipid bilayer

• embedded with proteins

• hydrophilic tail face out, hydrophilic heads face out

Proteins function

• selective gates

• sensors of environmental conditions

• enzymes

Fluid Mosaic Model

Fluid- proteins drift about in lipid bilayer

Mosaic- different proteins scattered throughout

Selectively Permeable

Control point for what gets in – separates internal from external environments

Simple Diffusion

• no energy needed

• movement from high to low concentration

• speed depends on concentration

Osmosis

• simple diffusion of water

• hypertonic, hypotonic, isotonic

Facilitated Diffusion

down concentration gradient

Active Transport

• ATP or proton motive force

• against concentration gradient

Group Translocation

chemically alters compound

Electron Transport Chain

• Embedded in cytoplasmic membrane

• makes up a series of protein complexes an has a role in ATP generation

Protein secretion

active movement of proteins out of the cell