Chapter 7: Cell Membrane Structure AP Biology Chapter 7: Cell Membrane Structure

Fig: 7.7

LE 7-2 WATER Hydrophilic head Hydrophobic tail WATER

Hydrophobic region of protein LE 7-3 Hydrophilic region of protein Phospholipid bilayer Hydrophobic region of protein

Proteins of the Membrane

Fig: 7.7

Transport Enzymatic activity Signal transduction Signal Enzymes LE 7-9a Signal Enzymes Receptor ATP Transport Enzymatic activity Signal transduction

Cell-cell recognition Intercellular joining Attachment to the LE 7-9b Glyco- protein Cell-cell recognition Intercellular joining Attachment to the cytoskeleton and extra- cellular matrix (ECM)

Cholesterol of the Membrane

Movement of phospholipids LE 7-5a Lateral movement (~107 times per second) Flip-flop (~ once per month) Movement of phospholipids

Extracellular layer Proteins Knife Plasma membrane Cytoplasmic layer LE 7-4 Extracellular layer Proteins Knife Plasma membrane Cytoplasmic layer Extracellular layer Cytoplasmic layer

Cell – to – Cell Recognition

LE 7-15a EXTRACELLULAR FLUID Channel protein Solute CYTOPLASM

LE 7-15b Carrier protein Solute

Diffusion

Osmosis

LE 7-13 Hypotonic solution Isotonic solution Hypertonic solution Animal cell H2O H2O H2O H2O Lysed Normal Shriveled Plant cell H2O H2O H2O H2O Turgid (normal) Flaccid Plasmolyzed

Water Potential

LE 7-15a EXTRACELLULAR FLUID Channel protein Solute CYTOPLASM

LE 7-16 Cytoplasmic Na+ bonds to the sodium-potassium pump EXTRACELLULAR FLUID [Na+] high [K+] low Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ [Na+] low [K+] high ATP P Na+ P CYTOPLASM ADP Cytoplasmic Na+ bonds to the sodium-potassium pump Na+ binding stimulates phosphorylation by ATP. Phosphorylation causes the protein to change its conformation, expelling Na+ to the outside. K+ K+ K+ K+ K+ P P K+ Extracellular K+ binds to the protein, triggering release of the phosphate group. Loss of the phosphate restores the protein’s original conformation. K+ is released and Na+ sites are receptive again; the cycle repeats.

Facilitated diffusion LE 7-17 Passive transport Active transport ATP Diffusion Facilitated diffusion

Cell Voltage Gradient

Fig: 7.18

Fig: 7.19

Phagocytosis & Pinocytosis

RECEPTOR-MEDIATED ENDOCYTOSIS LE 7-20c RECEPTOR-MEDIATED ENDOCYTOSIS Coat protein Receptor Coated vesicle Coated pit Ligand A coated pit and a coated vesicle formed during receptor- mediated endocytosis (TEMs). Coat protein Plasma membrane 0.25 µm