1. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Human Anatomy & Physiology SEVENTH EDITION Elaine N. Marieb Katja Hoehn PowerPoint ® Lecture Slides prepared by Vince Austin, Bluegrass Technical and Community College C H A P T E R 3 Cells: The Living Units P A R T A

2. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Cell Theory  The cell is the basic structural and functional unit of life  Organism’s activity depends on individual and collective activity of cells  Biochemical activities of cells are directed by subcellular structure  Continuity of life has a cellular basis (reproduction)

3. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 3.2 Secretion being released from cell by exocytosis Peroxisome Ribosomes Rough endoplasmic reticulum Nucleus Nuclear envelope Chromatin Golgi apparatus Nucleolus Smooth endoplasmic reticulum Cytosol Lysosome Mitochondrion Centrioles Centrosome matrix Microtubule Microvilli Microfilament Intermediate filaments Plasma membrane

4. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Plasma Membrane  Separates intracellular fluids from extracellular fluids  Plays a dynamic role in cellular activity Plasma membrane

5. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Plasma membrane with glycocalyx  Glycocalyx is a covering of glycoproteins on the cell surface that provides highly specific biological markers by which cells recognize one another

6. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Fluid Mosaic Model  Bilayer of lipids (fats) imbedded with proteins PLAY Membrane Structure Carbohydrate chain Lipid bilayer protein

7. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Fluid Mosaic Model cont.  Bilayer consists of phospholipids, cholesterol and glycolipids  Glycolipids are lipids with bound carbohydrate  Phospholipids have 2 poles--hydrophobic (repel water) and hydrophilic (attracted to water)  Glycoprotein are carbohydrates bound to a protein molecule Lipid molecule

8. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Fluid Mosaic Model Figure 3.3

9. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Functions of Membrane Proteins  1.Transport  2.Enzymatic activity  3.Receptors for signal transduction Figure 3.4.1

10. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Functions of Membrane Proteins  Intercellular adhesion  Cell-cell recognition  Attachment to cytoskeleton and extracellular matrix Figure 3.4.2 Structural ProteinStructural Protein

11. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Plasma Membrane Surfaces  Vary in the kind and amount of lipids they contain  Glycolipids are found only in the outer membrane surface  20% of all membrane lipid is cholesterol

12. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Membrane Junctions  1.Tight junction – impermeable junction that encircles the cell

13. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Membrane Junctions (cont.)  2. Desmosome – anchoring junction scattered along the sides of cells

14. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Membrane junctions (cont)  3. Gap junction – a connection that allows chemical substances to pass between cells

15. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Membrane Junctions: Tight Junction Figure 3.5a

16. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Membrane Junctions: Desmosome Figure 3.5b

17. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Membrane Junctions: Gap Junction Figure 3.5c Stop p. 70

18. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Passive Membrane Transport: Diffusion  Diffusion= the tendency of molecules or ions to scatter evenly throughout the environment.  Move from area of high concentration to area of lower concentration until equilibrium is reached. (no net change- molecules move back and forth)  NO MEMBRANE NECESSARY Force= kinetic energy Speed influenced by: 1.Molecule size -- smaller goes faster 2.Temperature -- warmer goes faster

19. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Passive Transport (cont)  Simple diffusion – nonpolar substances move across the plasma membrane ‘unassisted’  1.Will move across if molecule is lipid soluble  2. Small enough to go through membrane channels  3. Unassisted water (H2O) = OSMOSIS  4. Ex: oxygen, carbon dioxide, fat-soluble vitamins

20. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Passive transport (cont)  Facilitated diffusion – materials unable to pass through the lipid bilayer  1. Bind to protein carriers and ferried across membrane  2. Move through water-filled protein channels  3.Transport of glucose, amino acids, and ions

21. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Carrier Proteins  Are integral transmembrane proteins  Used for certain polar molecules including sugars and amino acids

22. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

23. Diffusion Through the Plasma Membrane Figure 3.7 Extracellular fluid Cytoplasm Lipid- soluble solutes (a) Simple diffusion directly through the phospholipid bilayer

24. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Diffusion Through the Plasma Membrane Figure 3.7 Lipid-insoluble solutes (b) Carrier-mediated facilitated diffusion via protein carrier specific for one chemical; binding of substrate causes shape change in transport protein

25. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Diffusion Through the Plasma Membrane Figure 3.7 Small lipid- insoluble solutes (c) Channel-mediated facilitated diffusion through a channel protein; mostly ions selected on basis of size and charge

26. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Diffusion Through the Plasma Membrane Figure 3.7 (d) Osmosis, diffusion through a specific channel protein (aquaporin) or through the lipid bilayer Lipid bilayer Water molecules

27. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Diffusion Through the Plasma Membrane Figure 3.7 Extracellular fluid Cytoplasm Lipid- soluble solutes Lipid bilayer Lipid-insoluble solutes Water molecules Small lipid- insoluble solutes (a) Simple diffusion directly through the phospholipid bilayer (c) Channel-mediated facilitated diffusion through a channel protein; mostly ions selected on basis of size and charge (b) Carrier-mediated facilitated diffusion via protein carrier specific for one chemical; binding of substrate causes shape change in transport protein (d) Osmosis, diffusion through a specific channel protein (aquaporin) or through the lipid bilayer

28. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings See … that wasn’t so hard

29. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Passive Membrane Transport: Osmosis  Occurs when the concentration of a solvent is different on opposite sides of a membrane  Diffusion of water across a semipermeable membrane  Osmolarity – total concentration of solute particles in a solution  Tonicity – how a solution affects cell volume PLAY Osmosis

30. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Effect of Membrane Permeability on Diffusion and Osmosis Figure 3.8a

31. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Effect of Membrane Permeability on Diffusion and Osmosis Figure 3.8b

32. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Passive Membrane Transport: Filtration  The passage of water and solutes through a membrane by hydrostatic pressure  Pressure gradient pushes solute-containing fluid from a higher-pressure area to a lower-pressure area

33. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Effects of Solutions of Varying Tonicity  Isotonic – solutions with the same solute concentration as that of the cytosol  Hypertonic – solutions having greater solute concentration than that of the cytosol  Hypotonic – solutions having lesser solute concentration than that of the cytosol