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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Human Anatomy & PhysiologySEVENTH EDITION
Elaine N. MariebKatja Hoehn
PowerPoint® Lecture Slides prepared by Vince Austin, Bluegrass Technical and Community College
C H
A P
T E
R
3Cells: 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 releasedfrom cell by exocytosis
Peroxisome
Ribosomes
Roughendoplasmicreticulum
NucleusNuclear envelopeChromatin
Golgi apparatus
Nucleolus
Smooth endoplasmicreticulum
Cytosol
Lysosome
Mitochondrion
Centrioles
Centrosomematrix
Microtubule
Microvilli
Microfilament
Intermediate filaments
Plasmamembrane
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Plasma Membrane
Separates intracellular fluids from extracellular fluids
Plays a dynamic role in cellular activity
Glycocalyx is a glycoprotein area abutting the cell that provides highly specific biological markers by which cells recognize one another
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
PLAYPLAY 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
Transport
Enzymatic activity
Receptors for signal transduction
Figure 3.4.1
PLAYPLAY Receptor Proteins
PLAYPLAY Enzymes
PLAYPLAY Transport Protein
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
PLAYPLAY Structural Proteins
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Plasma Membrane Surfaces
Differ 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
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Lipid Rafts
Make up 20% of the outer membrane surface
Composed of sphingolipids and cholesterol
Are concentrating platforms for cell-signaling molecules
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
PLAYPLAY 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
Carrier Proteins
Are integral transmembrane proteins
Show specificity for certain polar molecules including sugars and amino acids
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Diffusion Through the Plasma Membrane
Figure 3.7
Extracellular fluid
Cytoplasm
Lipid-solublesolutes
Lipidbilayer
Lipid-insolublesolutes
Watermolecules
Small lipid-insolublesolutes
(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-solublesolutes
(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-insolublesolutes
(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-insolublesolutes
(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
Lipidbilayer
Watermolecules
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Diffusion Through the Plasma Membrane
Figure 3.7
Extracellular fluid
Cytoplasm
Lipid-solublesolutes
Lipidbilayer
Lipid-insolublesolutes
Watermolecules
Small lipid-insolublesolutes
(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
PLAYPLAY 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 fluidK+ is released andNa+ sites are ready tobind Na+ again; thecycle repeats.
Cell ADP
Phosphorylationcauses theprotein tochange its shape.
Concentration gradientsof K+ and Na+
The shape change expels Na+ to the outside, and extracellular K+ binds.
Loss of phosphaterestores the originalconformation of thepump protein.
K+ binding triggersrelease of thephosphate group.
Binding of cytoplasmic Na+ to the pump proteinstimulates phosphorylationby ATP.Na+
Na+
Na+
Na+Na+
K+K+
K+
K+
Na+
Na+
Na+
ATPP
P
Na+
Na+Na+
K+
K+
P
P i
K+
K+
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 3.10
Cytoplasm
Extracellular fluid
Cell
Concentration gradientsof K+ and Na+
Na+
Na+
Na+
Na+Na+
K+K+
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 3.10
Cytoplasm
Extracellular fluid
Cell ADP
Concentration gradientsof K+ and Na+
Binding of cytoplasmic Na+ to the pump proteinstimulates phosphorylationby ATP.Na+
Na+
Na+
Na+Na+
K+K+
Na+
Na+
Na+
ATPP
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 3.10
Cytoplasm
Extracellular fluid
Cell ADP
Concentration gradientsof K+ and Na+
Binding of cytoplasmic Na+ to the pump proteinstimulates phosphorylationby ATP.Na+
Na+
Na+
Na+Na+
K+K+
Na+
Na+
Na+
ATPP
Phosphorylationcauses theprotein tochange its shape.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 3.10
Cytoplasm
Extracellular fluid
Cell ADP
Concentration gradientsof K+ and Na+
The shape change expels Na+ to the outside, and extracellular K+ binds.
Binding of cytoplasmic Na+ to the pump proteinstimulates phosphorylationby ATP.Na+
Na+
Na+
Na+Na+
K+K+
Na+
Na+
Na+
ATPP
P
Na+
Na+Na+
Phosphorylationcauses theprotein tochange its shape.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 3.10
Cytoplasm
Extracellular fluid
Cell ADP
Concentration gradientsof K+ and Na+
The shape change expels Na+ to the outside, and extracellular K+ binds.
K+ binding triggersrelease of thephosphate group.
Binding of cytoplasmic Na+ to the pump proteinstimulates phosphorylationby ATP.Na+
Na+
Na+
Na+Na+
K+K+
Na+
Na+
Na+
ATPP
P
Na+
Na+Na+
K+
K+
P
P i
Phosphorylationcauses theprotein tochange its shape.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 3.10
Cytoplasm
Extracellular fluid
Cell ADP
Concentration gradientsof K+ and Na+
The shape change expels Na+ to the outside, and extracellular K+ binds.
Loss of phosphaterestores the originalconformation of thepump protein.
K+ binding triggersrelease of thephosphate group.
Binding of cytoplasmic Na+ to the pump proteinstimulates phosphorylationby ATP.Na+
Na+
Na+
Na+Na+
K+K+
Na+
Na+
Na+
ATPP
P
Na+
Na+Na+
K+
K+
P
P i
K+
K+
Phosphorylationcauses theprotein tochange its shape.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 3.10
Cytoplasm
Extracellular fluidK+ is released andNa+ sites are ready tobind Na+ again; thecycle repeats.
Cell ADP
Phosphorylationcauses theprotein tochange its shape.
Concentration gradientsof K+ and Na+
The shape change expels Na+ to the outside, and extracellular K+ binds.
Loss of phosphaterestores the originalconformation of thepump protein.
K+ binding triggersrelease of thephosphate group.
Binding of cytoplasmic Na+ to the pump proteinstimulates phosphorylationby ATP.Na+
Na+
Na+
Na+Na+
K+K+
K+
K+
Na+
Na+
Na+
ATPP
P
Na+
Na+Na+
K+
K+
P
P i
K+
K+
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