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

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

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

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

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Fluid Mosaic Model  Double bilayer of lipids with imbedded, dispersed proteins  Bilayer consists of phospholipids, cholesterol, and glycolipids  Glycolipids are lipids with bound carbohydrate  Phospholipids have hydrophobic and hydrophilic bipoles PLAY Membrane Structure

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

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 PLAY Structural Proteins

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Membrane Junctions  Tight junction – impermeable junction that encircles the cell  Desmosome – anchoring junction scattered along the sides of cells  Gap junction – a nexus that allows chemical substances to pass between cells

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

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

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

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Passive Membrane Transport: Diffusion  Simple diffusion – nonpolar and lipid-soluble substances  Diffuse directly through the lipid bilayer  Diffuse through channel proteins PLAY Diffusion

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Passive Membrane Transport: Diffusion  Facilitated diffusion  Transport of glucose, amino acids, and ions  Transported substances bind carrier proteins or pass through protein channels

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

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Diffusion Through the Plasma Membrane Figure 3.7 Extracellular fluid Cytoplasm Lipid- soluble solutes (a) Simple diffusion directly through the phospholipid bilayer

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

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

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

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

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

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

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

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

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

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 3.10 Cytoplasm Extracellular fluid K + is released and Na + sites are ready to bind Na + again; the cycle repeats. Cell ADP Phosphorylation causes the protein to change its shape. Concentration gradients of K + and Na + The shape change expels Na + to the outside, and extracellular K + binds. Loss of phosphate restores the original conformation of the pump protein. K + binding triggers release of the phosphate group. Binding of cytoplasmic Na + to the pump protein stimulates phosphorylation by ATP. Na + K+K+ K+K+ K+K+ K+K+ ATP P P Na + K+K+ K+K+ P PiPi K+K+ K+K+

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 3.10 Cytoplasm Extracellular fluid K + is released and Na + sites are ready to bind Na + again; the cycle repeats. Cell ADP Phosphorylation causes the protein to change its shape. Concentration gradients of K + and Na + The shape change expels Na + to the outside, and extracellular K + binds. Loss of phosphate restores the original conformation of the pump protein. K + binding triggers release of the phosphate group. Binding of cytoplasmic Na + to the pump protein stimulates phosphorylation by ATP. Na + K+K+ K+K+ K+K+ K+K+ ATP P P Na + K+K+ K+K+ P PiPi K+K+ K+K+