WATER Hydrophilic head Hydrophobic tail WATER Figure 7.2 Figure 7.2 Phospholipid bilayer (cross section).

Phospholipid bilayer Hydrophobic regions of protein Figure 7.3 Phospholipid bilayer Figure 7.3 The original fluid mosaic model for membranes. Hydrophobic regions of protein Hydrophilic regions of protein

Figure 7.5 Fibers of extra- cellular matrix (ECM) Glyco- protein Carbohydrate Glycolipid EXTRACELLULAR SIDE OF MEMBRANE Figure 7.5 Updated model of an animal cell’s plasma membrane (cutaway view). Cholesterol Microfilaments of cytoskeleton Peripheral proteins Integral protein CYTOPLASMIC SIDE OF MEMBRANE

Mixed proteins after 1 hour Figure 7.7 RESULTS Membrane proteins Mixed proteins after 1 hour Mouse cell Figure 7.7 INQUIRY: Do membrane proteins move? Human cell Hybrid cell

Unsaturated hydrocarbon tails Saturated hydrocarbon tails Figure 7.8 Fluid Viscous Unsaturated hydrocarbon tails Saturated hydrocarbon tails (a) Unsaturated versus saturated hydrocarbon tails (b) Cholesterol within the animal cell membrane Figure 7.8 Factors that affect membrane fluidity. Cholesterol

(b) Enzymatic activity (c) Signal transduction Figure 7.10a Signaling molecule Receptor Enzymes ATP Figure 7.10 Some functions of membrane proteins. Signal transduction (a) Transport (b) Enzymatic activity (c) Signal transduction

(d) Cell-cell recognition (e) Intercellular joining Figure 7.10b Glyco- protein Figure 7.10 Some functions of membrane proteins. (d) Cell-cell recognition (e) Intercellular joining (f) Attachment to the cytoskeleton and extracellular matrix (ECM)

Transmembrane glycoproteins Figure 7.12 Secretory protein Transmembrane glycoproteins Golgi apparatus Vesicle ER ER lumen Glycolipid Figure 7.12 Synthesis of membrane components and their orientation in the membrane. Plasma membrane: Cytoplasmic face Transmembrane glycoprotein Extracellular face Secreted protein Membrane glycolipid

Membrane (cross section) Figure 7.13a Molecules of dye Membrane (cross section) WATER Figure 7.13 The diffusion of solutes across a synthetic membrane. Net diffusion Net diffusion Equilibrium (a) Diffusion of one solute

(b) Diffusion of two solutes Figure 7.13b Net diffusion Net diffusion Equilibrium Figure 7.13 The diffusion of solutes across a synthetic membrane. Net diffusion Net diffusion Equilibrium (b) Diffusion of two solutes

Lower concentration of solute (sugar) Higher concentration of solute Figure 7.14 Lower concentration of solute (sugar) Higher concentration of solute Same concentration of solute Sugar molecule H2O Selectively permeable membrane Figure 7.14 Osmosis. Osmosis

Hypotonic solution Isotonic solution Hypertonic solution Figure 7.15 Hypotonic solution Isotonic solution Hypertonic solution (a) Animal cell H2O H2O H2O H2O Lysed Normal Shriveled H2O Cell wall H2O H2O H2O (b) Plant cell Figure 7.15 The water balance of living cells. Turgid (normal) Flaccid Plasmolyzed Osmosis

50 m Contractile vacuole Figure 7.16 Figure 7.16 The contractile vacuole of Paramecium caudatum.

Facilitated diffusion ATP Figure 7.19 Passive transport Active transport Figure 7.19 Review: passive and active transport. Diffusion Facilitated diffusion ATP

ATP   EXTRACELLULAR FLUID   H Proton pump H H H   H  H Figure 7.20 ATP   EXTRACELLULAR FLUID   H Proton pump H H H   H  H Figure 7.20 A proton pump. CYTOPLASM 

Sucrose-H cotransporter Figure 7.21 ATP H   H Proton pump H H   H H H   H Sucrose-H cotransporter Diffusion of H Figure 7.21 Cotransport: active transport driven by a concentration gradient. Sucrose   Sucrose

Receptor-Mediated Endocytosis Figure 7.22 Phagocytosis Pinocytosis Receptor-Mediated Endocytosis EXTRACELLULAR FLUID Solutes Pseudopodium Receptor Plasma membrane Ligand Coat proteins Coated pit “Food” or other particle Coated vesicle Figure 7.22 Exploring: Endocytosis in Animal Cells Vesicle Food vacuole CYTOPLASM