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CELL BIOLOGY - Overview: Material/Energy is absorbed across the membrane (life is cellular)

CELL BIOLOGY - Overview: Material/Energy is absorbed across the membrane (life is cellular) It is metabolized - energy and products are harvested. (metabolism) The energy (and some products of digestion) are used to:. CELL BIOLOGY - Overview:

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CELL BIOLOGY - Overview: Material/Energy is absorbed across the membrane (life is cellular)

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  1. CELL BIOLOGY - Overview: Material/Energy is absorbed across the membrane (life is cellular) It is metabolized - energy and products are harvested. (metabolism) The energy (and some products of digestion) are used to:

  2. CELL BIOLOGY - Overview: Material/Energy is absorbed across the membrane (life is cellular) It is metabolized - energy and products are harvested. (metabolism) The energy (and some products of digestion) are used to: 1) build proteins (growth) which allow response.

  3. CELL BIOLOGY - Overview: Material/Energy is absorbed across the membrane (life is cellular) It is metabolized - energy and products are harvested. (metabolism) The energy (and some products of digestion) are used to: 1) build proteins (growth) which allow response. 2) replicate DNA and divide (cell division and reproduction)

  4. CELL BIOLOGY - Overview: Material/Energy is absorbed across the membrane (life is cellular) It is metabolized - energy and products are harvested. (metabolism) The energy (and some products of digestion) are used to: 1) build proteins (growth) which allow response. 2) replicate DNA and divide (cell division and reproduction) Which produces patterns of genetic relatedness among cells and organisms(evolutionary history)

  5. CELL BIOLOGY - Overview: A. Membranes - how stuff get in/out of cells 1. Structure

  6. CELL BIOLOGY - Overview: A. Membranes - how stuff get in/out of cells 1. Structure - phospholipids LE 7-2 WATER Hydrophilic head Hydrophobic tail WATER

  7. Lateral movement (~107 times per second) Flip-flop (~ once per month) LE 7-5 Movement of phospholipids Viscous Fluid More fluid as temps drop Saturated hydro- carbon tails Unsaturated hydrocarbon tails with kinks Membrane fluidity Keeps lipids separated and fluid as temps drop, but also… Locks lipids together at high temps and maintains membrane integrity…so acts as a thermal buffer… Cholesterol Cholesterol within the animal cell membrane

  8. Fibers of extracellular matrix (ECM) Glycoprotein Carbohydrates LE 7-7 Glycolipid EXTRACELLULAR SIDE OF MEMBRANE Cholesterol Microfilaments of cytoskeleton Integral protein Peripheral protein CYTOPLASMIC SIDE OF MEMBRANE

  9. CELL BIOLOGY - Overview: A. Membranes - how stuff get in/out of cells 1. Structure 2. Functions

  10. Signal Enzymes LE 7-9a Receptor ATP Enzymatic activity Transport Signal transduction Selective, regulated permeability

  11. Signal Enzymes LE 7-9a Receptor ATP Enzymatic activity Transport Signal transduction Selective, regulated permeability Especially useful for metabolic pathways where products of one reaction are substrates for another

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

  13. Transmembrane protein Helices are hydrophobic, loops are hydrophilic, and there is a hydrophilic channel

  14. CELL BIOLOGY - Overview: A. Membranes - how stuff get in/out of cells 1. Structure 2. Functions Types of "transport"

  15. Types of "transport" - DIFFUSION Molecules of dye Membrane (cross section) LE 7-11a WATER Net diffusion Net diffusion Equilibrium Diffusion of one solute Net movement of energy/matter from an area of high concentration to an area of low concentration.

  16. Types of "transport" - DIFFUSION LE 7-11b Net diffusion Net diffusion Equilibrium Equilibrium Net diffusion Net diffusion Diffusion of two solutes Energy and matter only responds to its own concentration gradient

  17. Lower concentration of solute (sugar) Higher concentration of sugar Same concentration of sugar LE 7-12 H2O Selectively permeable mem- brane: sugar mole- cules cannot pass through pores, but water molecules can - OSMOSIS: diffusion of water across a semi-permeable membrane from HI to LO water potential Water Potential: as solute conc. increases as pressure increases Osmosis

  18. Isotonic solution Hypertonic solution Hypotonic solution Animal cell 9% 15% H2O H2O H2O H2O 1% 9% Salt 9% Salt 9%Salt LE 7-13 Shriveled Normal Lysed Plant cell H2O H2O H2O H2O Flaccid Plasmolyzed Turgid (normal)

  19. Types of "transport" - FACILITATED DIFFUSION - for big or charged stuff EXTRACELLULAR FLUID LE 7-15a Solute Channel protein CYTOPLASM movement in the direction of the concentration gradient

  20. Types of "transport" - FACILITATED DIFFUSION - for big or charged stuff LE 7-15b Carrier protein Solute movement in the direction of the concentration gradient

  21. Types of "transport" - ACTIVE TRANSPORT AGAINST concentration gradient MUST use ENERGY Makes cell DIFFERENT FROM the environment. LE 7-17b ATP

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

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

  24. – EXTRACELLULAR FLUID + – ATP + H+ LE 7-18 H+ Proton pump H+ – + H+ H+ – + CYTOPLASM H+ – +

  25. – + H+ ATP H+ – + Proton pump H+ H+ LE 7-19 – + H+ – + H+ Diffusion of H+ Sucrose-H+ cotransporter H+ – + – + Sucrose

  26. Types of "transport" - Phagocytosis and Pinocytosis PHAGOCYTOSIS CYTOPLASM EXTRACELLULAR FLUID 1 µm LE 7-20a Pseudopodium Pseudopodium of amoeba “Food” or other particle Bacterium Food vacuole Food vacuole An amoeba engulfing a bacterium via phagocytosis (TEM)

  27. Types of "transport" - Phagocytosis and Pinocytosis PINOCYTOSIS LE 7-20b 0.5 µm Plasma membrane Pinocytosis vesicles forming (arrows) in a cell lining a small blood vessel (TEM). Vesicle

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

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