1. Slides 1 to 102
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

2. The Cell Membrane Key Note
Things tend to even out, unless something—like a cell membrane—prevents this from happening. Across a freely permeable or water permeable membrane, diffusion and osmosis will quickly eliminate concentration gradients.
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

3. The Cell Membrane Membrane Transport
Permeability – property that determines which substances can enter/leave the cytoplasm
Freely – any substance crosses
Selective – certain substances cross
Permeability factors
Molecular size/shape
Electrical charge
Lipid solubility
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

4. The Cell Membrane Membrane Transport Processes
Passive Transport – no energy expended
Diffusion (includes osmosis)
Filtration
Facilitated Transport (carrier-mediated)
Active Transport – energy expended
Carrier-Mediated
Vesicular Transport
Endocytosis
Exocytosis
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

5. The Cell Membrane Membrane Transport Definitions Diffusion Osmosis
Random movement down a concentration gradient (higher to lower [C])
Osmosis
Movement of water across a membrane down a gradient in osmotic pressure (lower to higher osmotic pressure)
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

6. The Cell Membrane
Diffusion
Figure 3-4

7. Diffusion Across Cell Membranes
The Cell Membrane
Diffusion Across Cell Membranes
Figure 3-5

8. The Cell Membrane
Osmosis
Figure 3-6

9. The Cell Membrane Osmotic Effects of Solutions on Cells
Isotonic—Cells maintain normal size and shape
Hypertonic—Cells lose water osmotically and shrink and shrivel
Hypotonic—Cells gain water osmotically and swell and may burst.
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

10. The Cell Membrane
Osmotic Flow across a Cell Membrane
Figure 3-7

11. The Cell Membrane Passive Membrane Transport Filtration
Hydrostatic pressure pushes on water
Water crosses membrane
Small solutes follow water through pores
Examples: blood pressure and urine formation
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

12. The Cell Membrane Carrier-Mediated Transport - Passive
Membrane proteins as carriers
Facilitated Diffusion (no ATP required)
Co-transport
Counter-transport
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

13. Facilitated Diffusion
The Cell Membrane
Facilitated Diffusion
Figure 3-8

14. Carrier-Mediated Transport – Active
Active transport (ATP consumed)
Independent of concentration gradients
Ion pumps
- Na+/K+ Exchange Pump

15. The Cell Membrane
The Sodium-Potassium Exchange Pump
Figure 3-9

16. The Cell Membrane Vesicular Transport Active Transport
Membranous vesicles move material into/out of cell
Types:
Endocytosis - movement into cell
Receptor-Mediated
Pinocytosis – cell drinking
Phagocytosis – cell eating
Exocytosis - Movement out of cell
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

17. EXTRACELLULAR FLUID Ligands Ligands binding to receptors Exocytosis
Receptor-Mediated Endocytosis
Ligands binding
to receptors
Target molecules (ligands) bind to receptors in cell membrane.
Exocytosis
Endocytosis
Ligand
receptors
Areas coated with ligands form deep pockets in membrane surface.
Pockets pinch off, forming vesicles.
Coated
vesicle
CYTOPLASM
Vesicles fuse with lysosomes.
Ligands are removed and absorbed into the cytoplasm.
Fusion
Detachment
The membrane containing the receptor molecules separates from the lysosome.
Lysosome
Ligands
removed
Fused vesicle
and lysosome
The vesicle returns to the surface.
Figure 3-10
1 of 8
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

18. Ligands Ligand receptors CYTOPLASM
EXTRACELLULAR
FLUID
Ligands
Receptor-Mediated Endocytosis
Ligands binding
to receptors
Target molecules (ligands) bind to receptors in cell membrane.
Ligand
receptors
CYTOPLASM
Figure 3-10
2 of 8
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

19. Ligands Ligand receptors CYTOPLASM
EXTRACELLULAR
FLUID
Ligands
Receptor-Mediated Endocytosis
Ligands binding
to receptors
Target molecules (ligands) bind to receptors in cell membrane.
Endocytosis
Ligand
receptors
Areas coated with ligands form deep pockets in membrane surface.
CYTOPLASM
Figure 3-10
3 of 8
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

20. Ligands Ligand receptors CYTOPLASM
EXTRACELLULAR
FLUID
Ligands
Receptor-Mediated Endocytosis
Ligands binding
to receptors
Target molecules (ligands) bind to receptors in cell membrane.
Endocytosis
Ligand
receptors
Areas coated with ligands form deep pockets in membrane surface.
Pockets pinch off, forming vesicles.
Coated
vesicle
CYTOPLASM
Figure 3-10
4 of 8
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

21. Ligands Ligand receptors CYTOPLASM Fused vesicle and lysosome
EXTRACELLULAR
FLUID
Ligands
Receptor-Mediated Endocytosis
Ligands binding
to receptors
Target molecules (ligands) bind to receptors in cell membrane.
Endocytosis
Ligand
receptors
Areas coated with ligands form deep pockets in membrane surface.
Pockets pinch off, forming vesicles.
Coated
vesicle
CYTOPLASM
Vesicles fuse with lysosomes.
Fusion
Lysosome
Fused vesicle
and lysosome
Figure 3-10
5 of 8
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

22. Ligands Ligand receptors CYTOPLASM Fused vesicle and lysosome
EXTRACELLULAR
FLUID
Ligands
Receptor-Mediated Endocytosis
Ligands binding
to receptors
Target molecules (ligands) bind to receptors in cell membrane.
Endocytosis
Ligand
receptors
Areas coated with ligands form deep pockets in membrane surface.
Pockets pinch off, forming vesicles.
Coated
vesicle
CYTOPLASM
Vesicles fuse with lysosomes.
Ligands are removed and absorbed into the cytoplasm.
Fusion
Lysosome
Fused vesicle
and lysosome
Figure 3-10
6 of 8
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

23. EXTRACELLULAR FLUID Ligands Ligands binding to receptors Endocytosis
Receptor-Mediated Endocytosis
Ligands binding
to receptors
Target molecules (ligands) bind to receptors in cell membrane.
Endocytosis
Ligand
receptors
Areas coated with ligands form deep pockets in membrane surface.
Pockets pinch off, forming vesicles.
Coated
vesicle
CYTOPLASM
Vesicles fuse with lysosomes.
Ligands are removed and absorbed into the cytoplasm.
Fusion
Detachment
The membrane containing the receptor molecules separates from the lysosome.
Lysosome
Ligands
removed
Fused vesicle
and lysosome
Figure 3-10
7 of 8
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

24. EXTRACELLULAR FLUID Ligands Ligands binding to receptors Exocytosis
Receptor-Mediated Endocytosis
Ligands binding
to receptors
Target molecules (ligands) bind to receptors in cell membrane.
Exocytosis
Endocytosis
Ligand
receptors
Areas coated with ligands form deep pockets in membrane surface.
Pockets pinch off, forming vesicles.
Coated
vesicle
CYTOPLASM
Vesicles fuse with lysosomes.
Ligands are removed and absorbed into the cytoplasm.
Fusion
Detachment
The membrane containing the receptor molecules separates from the lysosome.
Lysosome
Ligands
removed
Fused vesicle
and lysosome
The vesicle returns to the surface.
Figure 3-10
8 of 8
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

25. Vesicle Foreign object Undissolved residue
Phagocytosis
Cell membrane
of phagocytic
cell
Lysosomes
A phagocytic cell comes in contact with the foreign object and sends pseudopodia (cytoplasmic extensions) around it.
The pseudopodia approach one another and fuse to trap the material within the vesicle.
The vesicle moves into the cytoplasm.
Vesicle
Lysosomes fuse with the vesicle.
Foreign
object
This fusion activates digestive enzymes.
CYTOPLASM
Pseudopodium
(cytoplasmic
extension)
Undissolved
residue
The enzymes break down the structure of the phagocytized material.
EXTRACELLULAR FLUID
Residue is then ejected from the cell by exocytosis.
Figure 3-11
1 of 8
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

26. Phagocytosis Foreign object CYTOPLASM EXTRACELLULAR FLUID Figure 3-11
Cell membrane
of phagocytic
cell
A phagocytic cell comes in contact with the foreign object and sends pseudopodia (cytoplasmic extensions) around it.
Foreign
object
CYTOPLASM
Pseudopodium
(cytoplasmic
extension)
EXTRACELLULAR FLUID
Figure 3-11
2 of 8
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

27. Phagocytosis Foreign object CYTOPLASM EXTRACELLULAR FLUID Figure 3-11
Cell membrane
of phagocytic
cell
A phagocytic cell comes in contact with the foreign object and sends pseudopodia (cytoplasmic extensions) around it.
The pseudopodia approach one another and fuse to trap the material within the vesicle.
Foreign
object
CYTOPLASM
Pseudopodium
(cytoplasmic
extension)
EXTRACELLULAR FLUID
Figure 3-11
3 of 8
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

28. Vesicle Foreign object
Phagocytosis
Cell membrane
of phagocytic
cell
A phagocytic cell comes in contact with the foreign object and sends pseudopodia (cytoplasmic extensions) around it.
The pseudopodia approach one another and fuse to trap the material within the vesicle.
The vesicle moves into the cytoplasm.
Vesicle
Foreign
object
CYTOPLASM
Pseudopodium
(cytoplasmic
extension)
EXTRACELLULAR FLUID
Figure 3-11
4 of 8
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

29. Vesicle Foreign object
Phagocytosis
Cell membrane
of phagocytic
cell
Lysosomes
A phagocytic cell comes in contact with the foreign object and sends pseudopodia (cytoplasmic extensions) around it.
The pseudopodia approach one another and fuse to trap the material within the vesicle.
The vesicle moves into the cytoplasm.
Vesicle
Lysosomes fuse with the vesicle.
Foreign
object
CYTOPLASM
Pseudopodium
(cytoplasmic
extension)
EXTRACELLULAR FLUID
Figure 3-11
5 of 8
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

30. Vesicle Foreign object
Phagocytosis
Cell membrane
of phagocytic
cell
Lysosomes
A phagocytic cell comes in contact with the foreign object and sends pseudopodia (cytoplasmic extensions) around it.
The pseudopodia approach one another and fuse to trap the material within the vesicle.
The vesicle moves into the cytoplasm.
Vesicle
Lysosomes fuse with the vesicle.
Foreign
object
This fusion activates digestive enzymes.
CYTOPLASM
Pseudopodium
(cytoplasmic
extension)
EXTRACELLULAR FLUID
Figure 3-11
6 of 8
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

31. Vesicle Foreign object
Phagocytosis
Cell membrane
of phagocytic
cell
Lysosomes
A phagocytic cell comes in contact with the foreign object and sends pseudopodia (cytoplasmic extensions) around it.
The pseudopodia approach one another and fuse to trap the material within the vesicle.
The vesicle moves into the cytoplasm.
Vesicle
Lysosomes fuse with the vesicle.
Foreign
object
This fusion activates digestive enzymes.
CYTOPLASM
Pseudopodium
(cytoplasmic
extension)
The enzymes break down the structure of the phagocytized material.
EXTRACELLULAR FLUID
Figure 3-11
7 of 8
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

32. Vesicle Foreign object Undissolved residue
Phagocytosis
Cell membrane
of phagocytic
cell
Lysosomes
A phagocytic cell comes in contact with the foreign object and sends pseudopodia (cytoplasmic extensions) around it.
The pseudopodia approach one another and fuse to trap the material within the vesicle.
The vesicle moves into the cytoplasm.
Vesicle
Lysosomes fuse with the vesicle.
Foreign
object
This fusion activates digestive enzymes.
CYTOPLASM
Pseudopodium
(cytoplasmic
extension)
Undissolved
residue
The enzymes break down the structure of the phagocytized material.
EXTRACELLULAR FLUID
Residue is then ejected from the cell by exocytosis.
Figure 3-11
8 of 8
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

33. Coloring Workbook
The packet will be due the day before the test. You can now complete numbers 8, 9, 10 and 11.