1. Diffusion

2. Diffusion Passive Transport Movement of particles or molecules
Down a concentration gradient
Area of higher concentration to an higher of lower concentration
Molecules cross the cell membrane

3. Osmosis

4. Osmosis Diffusion of water Allows cells to maintain water balance
Osmotic Solutions
Isotonic
No net change of water occurs
Equilibrium
Hypotonic
Water moves inside the cell
Lower solute concentration than cytoplasm
Cell expands
Hypertonic
Water moves out
Higher solute concentration than cytoplasm
Cell shrinks

5. Osmotic Solutions

9. Facilitated Diffusion

10. Facilitated Diffusion
Diffusion through cell membrane
Use of transport proteins
Channel Proteins
Ions, sugar molecules, amino acids
Specific ( Na+ ions travel through Na+ ion channel)
Carrier Proteins
Substance binds to specific site
Protein changes shape

11. Active Transport

12. Active Transport Requires Energy Moves against a gradient
Utilize carrier proteins
Carrier proteins do not require the use of energy
Animal cells make use of Sodium –potassium pump

15. Sodium Potassium Pump

16. Endocytosis Phagocytosis Pinocytosis
Large substances cross via vesicles
Proteins
polysaccharides
Vesicles are membrane bound sac
Lipid bilayer
they can break off and refuse with the cell membrane
Movement of vesicle into cell: endocytosis
Lysosome will dissolve vesicle and release contents

18. Exocytosis Vesicle releases contents outside cell membrane Waste
Proteins modified by Golgi
Bacteria

19. Exocytosis

20. Endocytosis / Exocytosis

22. Cell Communication Chemical Signals Molecules directed at target cells
Long distance signals are carried by hormones
Targets
Hormones
Made in one part of the body
Distributed via bloodstream
Affect specific cells

25. Communication Environmental Signals Light
Target cells respond to few signals
Ones important to function
Response to signal is controlled by receptor proteins
Binding Specificity
bind to specific signal molecules
shape and signal specific
after binding, receptor signal changes shape
the shape change signifies a transfer of information

26. Response to Signals Cell response to Signals Change in permeability
Transport proteins may open or close
Activation of enzymes
Trigger chemical reactions
Second messenger
Acts as signal molecule
Changes cytoplasm and nucleus