Ch03 a, living units

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

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

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

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

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
PPLLAAYY Membrane Structure

Fluid Mosaic Model
Figure 3.3

Functions of Membrane Proteins
 Transport
PPLLAAYY Transport Protein
 Enzymatic activity
PPLLAAYY Enzymes
 Receptors for signal
transduction
Figure 3.4.1
PPLLAAYY Receptor Proteins

Functions of Membrane Proteins
 Intercellular adhesion
 Cell-cell recognition
 Attachment to
cytoskeleton and
extracellular matrix
Figure 3.4.2
PPLLAAYY Structural Proteins

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

Lipid Rafts
 Make up 20% of the outer membrane surface
 Composed of sphingolipids and cholesterol
 Are concentrating platforms for cell-signaling
molecules

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

Membrane Junctions: Tight Junction
Figure 3.5a

Membrane Junctions: Desmosome
Figure 3.5b

Membrane Junctions: Gap Junction
Figure 3.5c

Passive Membrane Transport: Diffusion
 Simple diffusion – nonpolar and lipid-soluble
substances
 Diffuse directly through the lipid bilayer
 Diffuse through channel proteins
PPLLAAYY Diffusion

Passive Membrane Transport: Diffusion
 Facilitated diffusion
 Transport of glucose, amino acids, and ions
 Transported substances bind carrier proteins or
pass through protein channels

Carrier Proteins
 Are integral transmembrane proteins
 Show specificity for certain polar molecules
including sugars and amino acids

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

Figure 3.7
Extracellular fluid
Cytoplasm
Lipid-soluble
solutes
(a) Simple diffusion
directly through the
phospholipid bilayer

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

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

Water
molecules
Figure 3.7
Lipid
bilayer
(d) Osmosis, diffusion through
a specific channel protein
(aquaporin) or through the
lipid bilayer

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
PPLLAAYY Osmosis

Effect of Membrane Permeability on Diffusion
and Osmosis
Figure 3.8a

Effect of Membrane Permeability on Diffusion
and Osmosis
Figure 3.8b

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

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

K+ is released and Extracellular fluid
Na+ sites are ready to
bind Na+ again; the
cycle repeats.
Na+ by ATP.
Na+
Na+
Cytoplasm
Binding of cytoplasmic
Na+ to the pump protein
stimulates phosphorylation
Na+
Na+
Na+
ATP
Cell ADP
P
Phosphorylation
causes the
protein to
change its shape.
K+ K+
Na+ Na+
Concentration gradients
of K+ and Na+
Na+ Na+
Na+
P
The shape change
expels Na+ to the
outside, and
extracellular K+ binds.
K+
K+
K+
K+
Loss of phosphate
restores the original
conformation of the
pump protein.
K+
K+
P
K+ binding triggers
release of the
phosphate group.
Pi

Extracellular fluid
Na+
Na+
Na+
Cytoplasm
Cell
K+ K+
Na+ Na+
of K+ and Na+

Extracellular fluid
Na+ by ATP.
Na+
Na+
Cytoplasm
Na+
Na+
Na+
ATP
Cell ADP
K+ K+
Na+ Na+
of K+ and Na+
P

Extracellular fluid
Na+ by ATP.
Na+
Na+
Cytoplasm
Na+
Na+
Na+
ATP
Cell ADP
K+ K+
Na+ Na+
of K+ and Na+
P
Phosphorylation
causes the
protein to
change its shape.

Extracellular fluid
Na+ by ATP.
Na+
Na+
Cytoplasm
Na+
Na+
Na+
ATP
Cell ADP
K+ K+
Na+ Na+
of K+ and Na+
P
Phosphorylation
causes the
protein to
change its shape.
Na+ Na+
Na+
P
The shape change
expels Na+ to the
outside, and

Extracellular fluid
Na+ by ATP.
Na+
Na+
Cytoplasm
Na+
Na+
Na+
ATP
Cell ADP
K+ K+
Na+ Na+
of K+ and Na+
P
Phosphorylation
causes the
protein to
change its shape.
Na+ Na+
Na+
P
The shape change
expels Na+ to the
outside, and
K+
K+
P
K+ binding triggers
release of the
phosphate group.
Pi

Extracellular fluid
Na+ by ATP.
Na+
Na+
Cytoplasm
Na+
Na+
Na+
ATP
Cell ADP
K+ K+
Na+ Na+
of K+ and Na+
P
Phosphorylation
causes the
protein to
change its shape.
Na+ Na+
Na+
P
The shape change
expels Na+ to the
outside, and
K+
K+
Loss of phosphate
restores the original
conformation of the
pump protein.
K+
K+
P
K+ binding triggers
release of the
phosphate group.
Pi

Ch03 a, living units

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