Cellular Transport Review

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

Lateral movement occurs 107 times per second. Figure 7.6 Lateral movement occurs 107 times per second. Flip-flopping across the membrane is rare ( once per month). Figure 7.6 The movement of phospholipids.

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)

Receptor (CD4) but no CCR5 Co-receptor (CCR5) Plasma membrane Figure 7.11 HIV Receptor (CD4) Receptor (CD4) but no CCR5 Co-receptor (CCR5) Plasma membrane Figure 7.11 IMPACT: Blocking HIV Entry into Cells as a Treatment for HIV Infections HIV can infect a cell that has CCR5 on its surface, as in most people. HIV cannot infect a cell lacking CCR5 on its surface, as in resistant individuals.

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 Cell wall H2O 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.

(a) A channel protein Channel protein Solute Carrier protein Solute Figure 7.17 EXTRACELLULAR FLUID (a) A channel protein Channel protein Solute CYTOPLASM Figure 7.17 Two types of transport proteins that carry out facilitated diffusion. Carrier protein Solute (b) A carrier protein

EXTRACELLULAR FLUID [Na] high [K] low Na Na [Na] low CYTOPLASM Figure 7.18-1 EXTRACELLULAR FLUID [Na] high [K] low Na Na CYTOPLASM [Na] low Na 1 [K] high Figure 7.18 The sodium-potassium pump: a specific case of active transport.

EXTRACELLULAR FLUID [Na] high [K] low Na Na Na Na Na [Na] low Figure 7.18-2 EXTRACELLULAR FLUID [Na] high [K] low Na Na Na Na Na [Na] low ATP CYTOPLASM Na P 1 [K] high 2 ADP Figure 7.18 The sodium-potassium pump: a specific case of active transport.

EXTRACELLULAR FLUID [Na] high Na Na [K] low Na Na Na Na Na Figure 7.18-3 EXTRACELLULAR FLUID [Na] high Na Na [K] low Na Na Na Na Na Na CYTOPLASM [Na] low ATP Na P P 1 [K] high 2 ADP 3 Figure 7.18 The sodium-potassium pump: a specific case of active transport.

EXTRACELLULAR FLUID [Na] high Na Na [K] low Na Na Na Na Na Figure 7.18-4 EXTRACELLULAR FLUID [Na] high Na Na [K] low Na Na Na Na Na Na CYTOPLASM [Na] low ATP Na P P 1 [K] high 2 ADP 3 K Figure 7.18 The sodium-potassium pump: a specific case of active transport. K P 4 P i

EXTRACELLULAR FLUID [Na] high Na Na [K] low Na Na Na Na Na Figure 7.18-5 EXTRACELLULAR FLUID [Na] high Na Na [K] low Na Na Na Na Na Na CYTOPLASM [Na] low ATP Na P P 1 [K] high 2 ADP 3 K Figure 7.18 The sodium-potassium pump: a specific case of active transport. K K K P 5 4 P i

EXTRACELLULAR FLUID [Na] high Na Na [K] low Na Na Na Na Na Figure 7.18-6 EXTRACELLULAR FLUID [Na] high Na Na [K] low Na Na Na Na Na Na ATP CYTOPLASM [Na] low Na P P 1 [K] high 2 ADP 3 K Figure 7.18 The sodium-potassium pump: a specific case of active transport. K K K K P 6 K 5 4 P i

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 CYTOPLASM  Figure 7.20 A proton pump.

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

Pseudopodium of amoeba Figure 7.22a Phagocytosis EXTRACELLULAR FLUID Solutes Pseudopodium of amoeba Pseudopodium Bacterium 1 m Food vacuole “Food” or other particle An amoeba engulfing a bacterium via phagocytosis (TEM). Figure 7.22 Exploring: Endocytosis in Animal Cells Food vacuole CYTOPLASM

Pinocytosis 0.5 m Plasma membrane Figure 7.22b Pinocytosis 0.5 m Plasma membrane Pinocytosis vesicles forming in a cell lining a small blood vessel (TEM). Figure 7.22 Exploring: Endocytosis in Animal Cells Vesicle

Receptor-Mediated Endocytosis Figure 7.22c Receptor-Mediated Endocytosis Receptor Plasma membrane Coat proteins Ligand Coat proteins Coated pit 0.25 m Figure 7.22 Exploring: Endocytosis in Animal Cells Coated vesicle Top: A coated pit. Bottom: A coated vesicle forming during receptor-mediated endocytosis (TEMs).

Passive transport: Facilitated diffusion Figure 7.UN01 Passive transport: Facilitated diffusion Channel protein Carrier protein Figure 7.UN01

Figure 7.UN02 Active transport Figure 7.UN02 ATP

0.01 M sucrose 0.01 M glucose 0.01 M fructose Figure 7.UN03 “Cell” “Environment” 0.03 M sucrose 0.02 M glucose 0.01 M sucrose 0.01 M glucose 0.01 M fructose Figure 7.UN03

(a) The structure of ATP Figure 8.8a Adenine Phosphate groups Ribose Figure 8.8 The structure and hydrolysis of adenosine triphosphate (ATP). (a) The structure of ATP

Adenosine triphosphate (ATP) Figure 8.8b Adenosine triphosphate (ATP) Energy Figure 8.8 The structure and hydrolysis of adenosine triphosphate (ATP). Inorganic phosphate Adenosine diphosphate (ADP) (b) The hydrolysis of ATP

Protein and vesicle moved Figure 8.10 Transport protein Solute ATP ADP P i P P i Solute transported (a) Transport work: ATP phosphorylates transport proteins. Vesicle Cytoskeletal track ATP ADP P i Figure 8.10 How ATP drives transport and mechanical work. ATP Motor protein Protein and vesicle moved (b) Mechanical work: ATP binds noncovalently to motor proteins and then is hydrolyzed.

Energy from catabolism (exergonic, energy-releasing processes) Figure 8.11 ATP H2O Energy from catabolism (exergonic, energy-releasing processes) Energy for cellular work (endergonic, energy-consuming processes) Figure 8.11 The ATP cycle. ADP P i