1. Transport and
The Cell Membrane

2. Transport
Transport: Involves the absorption and circulation of materials through out an organism
Absorption - process by which dissolved solids and gases enter the cells of an organism.
(Through cell membrane)

3. Transport Circulation – is accomplished by:
Diffusion of molecules across a membrane and into the organism
Cyclosis - streaming of the cytoplasm
3. Movement through the Endoplasmic Reticulum
4. Fluids that flow through tubes or vascular tissue

4. Cell Membrane Structure
Carbohydrate
Protein Molecule
Protein Molecule
Protein Channel
Lipid
Bilayer

5. About the Cell Membrane
Fluid mosaic model - the plasma membrane is composed of a double lipid layer in which large proteins float.
The cell membrane selectively regulates the entry and exit of materials.
Maintains homeostasis
Selectively permeable membrane
Semi-permeable membrane

6. Function of the Cell Membrane
Transport through the cell membrane may be passive or active.
Passive Transport - materials move through cell membrane from a region of high concentration to low concentration Hyperlink to Diffusion
No energy needed – the movement results from the random motion of particles

7. Diffusion
High Concentration
Low Concentration
Diffusion - movement of molecules from high to low concentration by random movement (Down the concentration gradient).
Dynamic Equilibrium is reached when the molecules spread out evenly on either side of a membrane. Molecules will move back and forth but there will be no net change.

8. Diffusion

9. Osmosis
The diffusion of water molecules through a membrane from a region of high to low concentration.
Molecules that dissolve in water (solute) have an effect on water concentration

10. Which process is occurring in each
of the pictures below? 1 2
Diffusion
Osmosis

11. Osmosis Terms Solute – something that dissolves in a fluid.
Solvent – the fluid (usually water) that a solute dissolves in.

12. Hypertonic Solution
A solution that has more solute (dissolved material) relative to another. Ex: Salt Solution

13. Hypotonic Solution
A solution that has less solute (dissolved material) relative to another. Ex: Pure Water

14. Isotonic Solution
A solution that has equal solute (dissolved material) relative to another. Ex: “Saline” Solution in hospital IVs.

15. Isotonic Solution

16. Plasmolysis
The shrinking of a cell due to outward osmosis.

17. Lysis (Animal Cell) Turgid (Plant Cell)
Lysis – Rupturing of a cell membrane due to the inward movement of water. Turgid – Vacuole fills with water, pressing the membrane against the cell wall.

18. Water balance between cells and their surroundings is crucial to organisms
ISOTONIC
SOLUTION
HYPOTONIC
SOLUTION
HYPERTONIC
SOLUTION
Osmosis causes cells to shrink in a hypertonic solution and swell in a hypotonic solution
The control of water balance (osmoregulation) is essential for organisms

19. Types of Cell Environments

20. Facilitated Diffusion
Carrier proteins form channels for diffusion of certain molecules.

21. Thought Questions
What happens when you put salt on a slug?

22. Thought Questions
Why do grocery stores spray fruits and vegetables with water?

23. Thought Questions What happens when you put sugar on strawberries?
(Water will move from a hypotonic to a hypertonic solution)

24. Active transport
Process in which energy (ATP) is used to move particles through a membrane.
Movement is generally from low to high concentration. (Against the concentration gradient)
High Concentration
Low Concentration

25. Sodium Potassium Pump

26. Pinocytosis (Endocytosis)
Vacuoles, which form at the cell surface, by pinching in, bring in large dissolved molecules.
Pinocytosis (Endocytosis)

27. Phagocytosis
The cell engulfs large undissolved molecules by forming pseudopods, that surround them.

29. Four Long Islanders Charged In Deadly Hazing