1. Transport Processes Passive processes Active processes
Diffusion of solutes
Diffusion of water (called osmosis)
Facilitated diffusion (requires a specific channel or a carrier molecule, but no energy is used)
Active processes
Various types of transporters are used, and energy is required.

2. Passive Transport Processes
Diffusion is the passive spread of particles through random motion, from areas of high concentration to areas of low concentration.
It is affected by the amount of
substance and the steepness of
the concentration gradient.
Temperature
Surface area
Diffusion distance

3. Passive Transport Processes
Channel-Mediated Facilitated Diffusion
Carrier-Mediated Facilitated Diffusion

4. Passive Transport Processes
An example of Channel-Mediated Facilitated Diffusion is the passage of potassium ions through a gated K+ Channel
An example of Carrier-Mediated Facilitated Diffusion is the passage of glucose across the cell membrane.

5. Passive Transport Processes
Osmosis is the net movement of water through a selectively permeable membrane from an area of high water concentration to one of lower water concentration.
Water can pass through plasma membrane in 2 ways:
through lipid bilayer by simple diffusion
through aquaporins (integral membrane proteins)

6. Passive Transport Processes
In the third tube, the force generated by the movement of water from the left to the right side is called osmotic pressure.

7. Passive Transport Processes
In the body, tonicity refers to the concentration of salt solutions in the blood and elsewhere. Since semipermeable membranes separate these fluid compartments, osmosis of water is free to occur between
any fluid space and another.
The effect of changing tonicity
is demonstrated in this graphic,
as water moves in and out
of red blood cells.

8. Active Transport Processes
Solutes can also be actively transported across a plasma membrane against their concentration gradient ([low] to [high]) by using energy (usually in the form of ATP).
The sodium-potassium pump is found in all cells.

9. Secondary Active Transport Mechanisms
Antiporters carry two substances across the membrane in opposite directions.
Symporters carry two substances across the membrane in the same direction.

10. Transport in Vesicles
Vesicle - a small spherical sac formed by budding off from a membrane
Endocytosis - materials move into a cell in a vesicle formed from the plasma membrane
three types: receptor-mediated endocytosis
phagocytosis
bulk-phase endocytosis (pinocytosis)
Exocytosis - vesicles fuse with the plasma membrane, releasing their contents into the extracellular fluid
Transcytosis - a combination of endocytosis and exocytosis

11. Receptor-Mediated Endocytosis

12. Phagocytosis

13. Bulk-phase Endocytosis

14. Interactions Animation
Transport
Transport Across the Plasma Membrane
Interactions Animation
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15. Transport Interactions Animations
Transport Across the Plasma Membrane
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16. Cytoplasm - 2 Components
1. Cytosol - intracellular fluid, surrounding the organelles
- The site of many chemical reactions
- Energy is usually released by these reactions.
- Reactions provide the building blocks for cell maintenance, structure, function and growth.
2. Organelles
- Specialized structures within the cell

17. The Cytoskeleton Network of protein filaments throughout the cytosol
Provides structural support for the cell

18. The Cytoskeleton Types Microfilaments Intermediate filaments
Microtubules

19. Organelles
Centrosome - located near the nucleus, consists of two centrioles and pericentriolar material

20. Organelles
Cilia - short, hair-like projections from the cell surface, move fluids along a cell surface
Flagella - longer than cilia, move an entire cell; only example is the sperm cell’s tail

21. Organelles

22. Organelles
Ribosomes - sites of protein synthesis

23. Organelles
Endoplasmic reticulum - network of membranes in the shape of flattened sacs or tubules
- Rough ER - connected to the nuclear envelope, a series of flattened sacs, surface is studded with ribosomes, produces various proteins
-Smooth ER - a network of membrane tubules, does not have ribosomes, synthesizes fatty acids and steroids, detoxifies certain drugs