1. Homeostasis and Transport
Unit 2 Sec 7.3
Homeostasis and Transport

2. I. Cell Wall A. Structure Composed of cellulose (__________)
Cellulose is a polysaccharide composed of smaller units called _______________ (glucose)
Glucose protects and supports cell

3. II. Cell Membrane Cell Membrane: Boundary of every cell
Controls what enter and leave cell through selective permeability
Boundary of every cell

4. II. Cell Membrane A. Membrane Lipids Phospholipid bilayer: Steriods:
Polar hydrophilic head
Nonpolar hydrophobic tail
Steriods:
Cholesterol provides strength and stability in movement

5. Cell Membrane

6. II. Cell Membrane B. Membrane Proteins
Integral proteins: embedded in lipid bilayer & extend from interior  exterior of CM

7. C. Fluid Mosaic Model
Phospholipid bilayer acts more like a fluid than a solid

8. III. Passive Transport
Passive Transport: the movement of substances across the cell membrane without the use of energy

9. III. Passive Transport How molecules move:
1. random fashion bouncing off other things
2. constantly in motion
From high to low concentrated area
Continue until equilibrium

10. III. Passive Transport Factors Affecting the Movement
Temperature: hot= cold=
Size of pores and particle size
Mass

11. Types of Passive Transport
Diffusion
Osmosis
Facilitated Diffusion

12. A. Diffusion
Diffusion: movement of molecules from an area of _______ concentration to an area of ________________
__________________________
Cool Science Trick
Concentration Gradient:

13. A. Diffusion
Equilibrium: concentration of substances in an area is _______
Results with:
Diffusion Across Membranes:

14. B. Osmosis
Osmosis: diffusion of ________ molecules across cell memb. from area of _______ con. to an area of ________ con.
Moves:

15. Who gets it?
What is diffusion?
What is equilibrium?
What is osmosis?

16. B. Osmosis Direction of Osmosis:
Hypotonic: Concentration of solute is lower outside the cell
Hypertonic: Concentration of solute is higher outside the cell
Isotonic: solutes in and outside the cell are equal

17. B. Osmosis How Cells Deal w/ Osmosis:
Certain unicellular organisms must maintain a low level of water
Use_______________ to get rid of extra water
Contractile Vacuole:

18. B. Osmosis How cells deal w/ Osmosis:
Plant root cells: need a __________ environment
Turgor Pressure:
Cytolysis
Hypertonic Environment.:
Plasmolysis:

19. C. Facilitated Diffusion
Facilitated Diffusion: substances require a ____________ for transport b/c it cannot diffuse through membrane
Molecules that use this transport:
Too big
Not charged
monomers

20. D. Diffusion through ion channels
Ion Channel: pathway for specific ion to pass through cell membrane
Stimuli will control gates to channels:
__________________

21. IV. Active Transport (AT)
1) AT: movement of materials from a area of ______ concentration to a _______ concentration using energy
2) Molecule is ___________ or not compatible with cell

22. IV. Active Transport 3) Bulk Transport:
Used to transport macromolecules or a large quantity of substance
A) Endocytosis: a cell will engulf external substances into cell

23. IV. Active Transport A. Endocytosis (continued) -2 Types
1) Pinocytosis: cell ___________
2) Phagocytosis: cell __________

24. Endocytosis and Exocytosis

25. IV. Active Transport
B) Exocytosis: process to remove materials from cell
a) vesicle w/in the cell is sent to cell membrane
b) vesicle fuses w/ the cell membrane & releases substance

26. IV. Active Transport C. Pumps:
Proteins are embedded in the cell membrane
Molecules fit into the protein and are moved across from a _________ to _________ concentration