1. 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
3
Cells: The
Living Units
P A R T B

2. Active Transport
 Uses ATP to move solutes across a membrane
 Requires carrier proteins
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

3. Types of Active Transport
 Symport system – two substances are moved
across a membrane in the same direction
 Antiport system – two substances are moved
across a membrane in opposite directions
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

4. Types of Active Transport
 Primary active transport – hydrolysis of ATP
phosphorylates the transport protein causing
conformational change
 Secondary active transport – use of an exchange
pump (such as the Na+-K+ pump) indirectly to
drive the transport of other solutes
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

5. Types of Active Transport
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Figure 3.11

6. Vesicular Transport
 Transport of large particles and macromolecules
across plasma membranes
 Exocytosis – moves substance from the cell
interior to the extracellular space
 Endocytosis – enables large particles and
macromolecules to enter the cell
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

7. Vesicular Transport
 Transcytosis – moving substances into, across, and
then out of a cell
 Vesicular trafficking – moving substances from
one area in the cell to another
 Phagocytosis – pseudopods engulf solids and bring
them into the cell’s interior
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8. Vesicular Transport
 Fluid-phase endocytosis – the plasma membrane
infolds, bringing extracellular fluid and solutes into
the interior of the cell
 Receptor-mediated endocytosis – clathrin-coated
pits provide the main route for endocytosis and
transcytosis
 Non-clathrin-coated vesicles – caveolae that are
platforms for a variety of signaling molecules
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9. Exocytosis
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Figure 3.12a

10. Clathrin-Mediated Endocytosis
Extracellular Cytoplasm
fluid
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Figure 3.13a
Recycling of
membrane and
receptors (if present)
to plasma membrane
Extracellular
fluid
Plasma
membrane
Detachment
of clathrin-coated
vesicle
Clathrin-coated
vesicle
Uncoated
vesicle
Uncoating
Uncoated
vesicle
fusing with
endosome
Exocytosis
of vesicle
contents
Endosome
Transcytosis
To lysosome
for digestion
and release
of contents
Clathrin-coated
pit
Plasma
membrane
Ingested
substance
Clathrin
protein
(a) Clathrin-mediated endocytosis
2
1
3

11. Clathrin-Mediated Endocytosis
Clathrin-coated
pit
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.13a
Extracellular Cytoplasm
fluid
Extracellular
fluid
Plasma
membrane
Plasma
membrane
Ingested
substance
(a) Clathrin-mediated endocytosis

12. Clathrin-Mediated Endocytosis
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.13a
Extracellular Cytoplasm
fluid
Extracellular
fluid
Plasma
membrane
Detachment
of clathrin-coated
vesicle
Clathrin-coated
vesicle
Clathrin-coated
pit
Plasma
membrane
Ingested
substance
(a) Clathrin-mediated endocytosis

13. Clathrin-Mediated Endocytosis
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.13a
Extracellular Cytoplasm
fluid
Extracellular
fluid
Plasma
membrane
Detachment
of clathrin-coated
vesicle
Clathrin-coated
vesicle
Uncoated
vesicle
Uncoating
Uncoated
vesicle
fusing with
endosome
Endosome
Clathrin-coated
pit
Plasma
membrane
Ingested
substance
Clathrin
protein
(a) Clathrin-mediated endocytosis

14. Clathrin-Mediated Endocytosis
Extracellular Cytoplasm
fluid
1
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.13a
Recycling of
membrane and
receptors (if present)
to plasma membrane
Extracellular
fluid
Plasma
membrane
Detachment
of clathrin-coated
vesicle
Clathrin-coated
vesicle
Uncoated
vesicle
Uncoating
Uncoated
vesicle
fusing with
endosome
Endosome
Clathrin-coated
pit
Plasma
membrane
Ingested
substance
Clathrin
protein
(a) Clathrin-mediated endocytosis

15. Clathrin-Mediated Endocytosis
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.13a
Extracellular Cytoplasm
fluid
Extracellular
fluid
Plasma
membrane
Detachment
of clathrin-coated
vesicle
Clathrin-coated
vesicle
Uncoated
vesicle
Uncoating
Uncoated
vesicle
fusing with
endosome
Endosome
To lysosome
for digestion
and release
of contents
Clathrin-coated
pit
Plasma
membrane
Ingested
substance
Clathrin
protein
(a) Clathrin-mediated endocytosis
2

16. Clathrin-Mediated Endocytosis
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.13a
Extracellular Cytoplasm
fluid
Extracellular
fluid
Plasma
membrane
Detachment
of clathrin-coated
vesicle
Clathrin-coated
vesicle
Uncoated
vesicle
Uncoating
Uncoated
vesicle
fusing with
endosome
Exocytosis
of vesicle
contents
Endosome
Transcytosis
Clathrin-coated
pit
Plasma
membrane
Ingested
substance
Clathrin
protein
(a) Clathrin-mediated endocytosis
3

17. Clathrin-Mediated Endocytosis
Extracellular Cytoplasm
fluid
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.13a
Recycling of
membrane and
receptors (if present)
to plasma membrane
Extracellular
fluid
Plasma
membrane
Detachment
of clathrin-coated
vesicle
Clathrin-coated
vesicle
Uncoated
vesicle
Uncoating
Uncoated
vesicle
fusing with
endosome
Exocytosis
of vesicle
contents
Endosome
Transcytosis
To lysosome
for digestion
and release
of contents
Clathrin-coated
pit
Plasma
membrane
Ingested
substance
Clathrin
protein
(a) Clathrin-mediated endocytosis
2
1
3

18. Phagocytosis
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Figure 3.13b

19. Receptor Mediated Endocytosis
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.13c

20. Passive Membrane Transport – Review
Process Energy Source Example
Simple diffusion Kinetic energy Movement of O2 through membrane
Facilitated diffusion Kinetic energy Movement of glucose into cells
Osmosis Kinetic energy Movement of H2O in & out of cells
Filtration Hydrostatic pressure Formation of kidney filtrate
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

21. Active Membrane Transport – Review
Process Energy Source Example
Active transport of solutes ATP
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Movement of ions across
membranes
Exocytosis ATP Neurotransmitter secretion
Endocytosis ATP White blood cell phagocytosis
Fluid-phase endocytosis ATP Absorption by intestinal cells
Receptor-mediated endocytosis ATP Hormone and cholesterol uptake
Endocytosis via caveoli ATP Cholesterol regulation
Endocytosis via coatomer
vesicles
ATP
Intracellular trafficking of
molecules

22. Membrane Potential
 Voltage across a membrane
 Resting membrane potential – the point where K+
potential is balanced by the membrane potential
 Ranges from –20 to –200 mV
 Results from Na+ and K+ concentration gradients
across the membrane
 Differential permeability of the plasma membrane
to Na+ and K+
 Steady state – potential maintained by active
transport of ions
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

23. Generation and Maintenance of Membrane
Potential
PLAY InterActive Physiology ®:
Nervous System I: The Membrane Potential
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.15

24. Cell Adhesion Molecules (CAMs)
 Anchor cells to the extracellular matrix
 Assist in movement of cells past one another
 Rally protective white blood cells to injured or
infected areas
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

25. Roles of Membrane Receptors
 Contact signaling – important in normal
development and immunity
 Electrical signaling – voltage-regulated “ion gates”
in nerve and muscle tissue
 Chemical signaling – neurotransmitters bind to
chemically gated channel-linked receptors in nerve
and muscle tissue
 G protein-linked receptors – ligands bind to a
receptor which activates a G protein, causing the
release of a second messenger, such as cyclic AMP
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

26. Operation of a G Protein
 An extracellular ligand (first messenger), binds to
a specific plasma membrane protein
 The receptor activates a G protein that relays the
message to an effector protein
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

27. Operation of a G Protein
 The effector is an enzyme that produces a second
messenger inside the cell
 The second messenger activates a kinase
 The activated kinase can trigger a variety of
cellular responses
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

28. Operation of a G Protein
First messenger
(ligand)
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.16
Extracellular fluid
Cytoplasm
Inactive
second
messenger
Effector
(e.g., enzyme)
Active
second
messenger
(e.g., cyclic
AMP)
Activated
(phosphorylated)
kinases
Cascade of cellular responses
(metabolic and structural changes)
Membrane
receptor
G protein
1
2
3 4
5
6

29. Operation of a G Protein
1
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.16
Extracellular fluid
Cytoplasm
First messenger
(ligand)
Membrane
receptor

30. Operation of a G Protein
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.16
Extracellular fluid
Cytoplasm
First messenger
(ligand)
Membrane
receptor
G protein
1
2

31. Operation of a G Protein
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.16
Extracellular fluid
Cytoplasm
Effector
(e.g., enzyme)
First messenger
(ligand)
Membrane
receptor
G protein
1
2
3

32. Operation of a G Protein
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.16
Extracellular fluid
Cytoplasm
Inactive
second
messenger
Effector
(e.g., enzyme)
First messenger
(ligand)
Active
second
messenger
(e.g., cyclic
AMP)
Membrane
receptor
G protein
1
2
3 4

33. Operation of a G Protein
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.16
Extracellular fluid
Cytoplasm
Inactive
second
messenger
Effector
(e.g., enzyme)
Activated
(phosphorylated)
kinases
First messenger
(ligand)
Active
second
messenger
(e.g., cyclic
AMP)
Membrane
receptor
G protein
1
2
3 4
5

34. Operation of a G Protein
First messenger
(ligand)
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.16
Extracellular fluid
Cytoplasm
Inactive
second
messenger
Effector
(e.g., enzyme)
Active
second
messenger
(e.g., cyclic
AMP)
Activated
(phosphorylated)
kinases
Cascade of cellular responses
(metabolic and structural changes)
Membrane
receptor
G protein
1
2
3 4
5
6

35. Cytoplasm
 Cytoplasm – material between plasma membrane
and the nucleus
 Cytosol – largely water with dissolved protein,
salts, sugars, and other solutes
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36. Cytoplasm
 Cytoplasmic organelles – metabolic machinery of
the cell
 Inclusions – chemical substances such as
glycosomes, glycogen granules, and pigment
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

37. Cytoplasmic Organelles
 Specialized cellular compartments
 Membranous
 Mitochondria, peroxisomes, lysosomes,
endoplasmic reticulum, and Golgi apparatus
 Nonmembranous
 Cytoskeleton, centrioles, and ribosomes
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

38. Mitochondria
 Double membrane structure with shelf-like cristae
 Provide most of the cell’s ATP via aerobic cellular
respiration
 Contain their own DNA and RNA
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39. Mitochondria
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.17a, b

40. Ribosomes
 Granules containing protein and rRNA
 Site of protein synthesis
 Free ribosomes synthesize soluble proteins
 Membrane-bound ribosomes synthesize proteins to
be incorporated into membranes
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

41. Endoplasmic Reticulum (ER)
 Interconnected tubes and parallel membranes
enclosing cisternae
 Continuous with the nuclear membrane
 Two varieties – rough ER and smooth ER
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

42. Endoplasmic Reticulum (ER)
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.18a, c

43. Rough (ER)
 External surface studded with ribosomes
 Manufactures all secreted proteins
 Responsible for the synthesis of integral membrane
proteins and phospholipids for cell membranes
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

44. Signal Mechanism of Protein Synthesis
 mRNA – ribosome complex is directed to rough
ER by a signal-recognition particle (SRP)
 SRP is released and polypeptide grows into
cisternae
 The protein is released into the cisternae and sugar
groups are added
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

45. Signal Mechanism of Protein Synthesis
 The protein folds into a three-dimensional
conformation
 The protein is enclosed in a transport vesicle and
moves toward the Golgi apparatus
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

46. Signal Mechanism of Protein Synthesis
Signal
sequence
Signal-recognition
particle
(SRP)
Receptor
site
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.19
Cytosol
Ribosomes
mRNA
Coatomer-coated
transport
vesicle
Transport
vesicle
budding off
Released
glycoprotein
ER
cisterna
ER
membrane
Sugar
group
Signal
sequence
Growing removed
polypeptide
1
2
3
4
5

47. Signal Mechanism of Protein Synthesis
Signal
sequence
Signal-recognition
particle
(SRP)
Receptor
site
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.19
Cytosol
mRNA
ER
cisterna
ER
membrane
1

48. Signal Mechanism of Protein Synthesis
Signal
sequence
Signal-recognition
particle
(SRP)
Receptor
site Growing
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.19
Cytosol
mRNA
ER
cisterna
ER
membrane
polypeptide
1
2

49. Signal Mechanism of Protein Synthesis
Signal
sequence
Signal-recognition
particle
(SRP)
Receptor
site
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.19
Cytosol
Ribosomes
mRNA
ER
cisterna
ER
membrane
Signal
sequence
Growing removed
polypeptide
1
2
3

50. Signal Mechanism of Protein Synthesis
Signal
sequence
Signal-recognition
particle
(SRP)
Receptor
site
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.19
Cytosol
Ribosomes
mRNA
Released
glycoprotein
ER
cisterna
ER
membrane
Signal
sequence
Growing removed
polypeptide
1
2
3
4

51. Signal Mechanism of Protein Synthesis
Signal
sequence
Signal-recognition
particle
(SRP)
Receptor
site
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.19
Cytosol
Ribosomes
mRNA
Transport
vesicle
budding off
Released
glycoprotein
ER
cisterna
ER
membrane
Sugar
group
Signal
sequence
Growing removed
polypeptide
1
2
3
4
5

52. Signal Mechanism of Protein Synthesis
Signal
sequence
Signal-recognition
particle
(SRP)
Receptor
site
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.19
Cytosol
Ribosomes
mRNA
Coatomer-coated
transport
vesicle
Transport
vesicle
budding off
Released
glycoprotein
ER
cisterna
ER
membrane
Sugar
group
Signal
sequence
Growing removed
polypeptide
1
2
3
4
5

53. Smooth ER
 Tubules arranged in a looping network
 Catalyzes the following reactions in various organs
of the body
 In the liver – lipid and cholesterol metabolism,
breakdown of glycogen and, along with the
kidneys, detoxification of drugs
 In the testes – synthesis of steroid-based hormones
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

54. Smooth ER
 Catalyzes the following reactions in various organs
of the body (continued)
 In the intestinal cells – absorption, synthesis, and
transport of fats
 In skeletal and cardiac muscle – storage and release
of calcium
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings