1. Passive Transport

2. Passive Transport Cell Membranes help to maintain homeostasis
Substances are able to cross through
Without using energy
Passive Transport

3. Diffusion
The most simple form of passive transport is called Diffusion
The movement of molecules from a higher concentrated area to a lower concentrated area
How does diffusion work?
Kinetic energy of molecules

4. Diffusion
Concentration Gradient – the difference in the concentration of molecules across a distance
Once the two areas are of equal concentration equilibrium is reached
Example

5. Simple Diffusion The diffusion of molecules across a membrane
Only some can diffuse across
Size – they can fit through the pores
Type – they can be dissolved in lipids (Carbon dioxide, Oxygen)
Type of membrane

6. Osmosis Every solution has two parts
Solute- the sugar
Solvent – the water
Both of these can diffuse to maintain homeostasis
Osmosis- water molecules going from a higher concentration to a lower concentration

7. Osmosis The direction of osmosis depends on the solution
Hypotonic- solution has less solute molecules than cytoplasm of the cell
Hypertonic- solution has more solute molecules than the cytoplasm of the cell
The water is going to try and create homeostasis. Draw it!

8. Osmosis Water will always move from Hypotonic to Hypertonic!
Isotonic– concentrations are equal inside and outside of the cell

9. Adaptations How do cells deal with a hypotonic environment?
Unicellular freshwater organisms
Don’t need as much water in their cytosol
Contractile vacuoles pg. 99
(not passive transport)

10. Adaptations Plant cells and their environment
hypotonic
Turgor pressure – the pressure that water molecules exert on the cell wall
How do plant cells keep from exploding?
Cell walls!

11. Adaptations What happens to plant cells in a hypertonic environment?
Plasmolysis- when turgor pressure is lost, and the cell shrinks away from the cell wall
Reason for plants wilting

12. Adaptations Some cells do not have any adaptations (Red blood cells)
No contractile vacuoles
No solute pumps
No cell walls
How are they affected?
Cytolysis – the bursting of cells

13. Facilitated Diffusion
Facilitated Diffusion – passive transport for molecules not able to diffuse through the membrane
To big to fit through the membrane
Not able to be dissolved in lipids
Glucose is a good example

14. Facilitated Diffusion
Carrier Proteins – assist molecules through the membrane
Molecules bind to the protein
The protein changes shape
The molecule is released on the other side
The protein returns to its original state

15. Ion channels
Ion Channels- specific proteins that allow certain ions to pass (sodium, potassium, calcium, chloride)
Each channel is specific to a certain ion
Some have gates

16. Active transport

17. Active Transport
Cells must move materials from areas of lower concentration to areas of higher concentration
Active Transport– the movement of materials from low concentrations to high concentrations
Up the concentration gradient
How is this different from passive transport?

18. Cell Membrane Pumps
Move molecules from low concentrations to high concentrations
Carrier Proteins – we meet again…
Facilitated diffusion vs. sodium potassium pump
What is the difference?

19. Cell membrane pumps
Sodium-Potassium pump– specific carrier protein, only carries Sodium and Potassium (page 104)
pumps Sodium (Na+) out
Pumps Potassium (K+) in
Animal cells need more Sodium outside of the cell, and potassium inside of the cell to function properly

20. Sodium-Potassium Pump
Three Na+ ions (sodium) attach from inside cell
ATP drops off some energy
Carrier protein changes shape (Na+ released)
Two K+ ions (Potassium) attach from outside the cell
The dropped of energy is released
Carrier Protein changes back (K+ released)
Cycle starts all over again
450 Sodium (Na+) per second!
How many Potassium?

22. Movement in Vesicles Some things are to large for proteins to assist
What should they do?
Vesicles– membrane bound organelle containing materials for the cell
The materials never become part of the cell
Why not?

23. Movement in Vesicles
Endocytosis– the process by which cells ingest external fluid (page 105)
they fuse to membrane bound organelles to deliver the contents
Pinocytosis– transport of solutes (fluids)
Phagocytosis– transport of large particles (cells)
Phagocytes– ingest bacteria and allow lysosomes to destroy it

24. Movement in Vesicles
Exocytosis– substance is released from the cell through a vesicle
Proteins, waste products, toxins
Exit is very similar to entrance
It is the reverse of Endocytosis

25. The Krebs Cycle The Electron Transport Chain Aerobic Respiration!

26. Mitochondria What is Aerobic Respiration?
The Mitochondria is where energy comes from
Energy is formed in these two cycles
The Krebs Cycle
The Electron Transport Chain

27. Mitochondria The Krebs cycle happens within the Matrix
The Electron Transport chain happens on the inner membrane

28. Krebs Cycle
Krebs Cycle- A six step process that produces CO2, ATP, NADH, and FADH2
Produces 2 Carbon Dioxide molecules
Produces 2 ATP Molecules
Produces 6 NADH molecules
(transporter)
Produces 2 FADH2

29. Krebs Cycle
The Krebs Cycle uses a broken down form of glucose to create energy
Even though the Krebs Cycle only produces 2 ATP
It provides the Electron Transport Chain with the molecules it needs to make energy

31. Krebs Cycle NADH and FADH2 are sent to the inner membrane
They make more ATP through the Electron Transport Chain
Proteins in a membrane that transfer electrons to each other

32. The Electron Transport Chain
In Depth Explanation of the Electron Transport Chain
Discuss what is happening
Where were the Carrier Proteins?
What was the Concentration Gradient?
Active or Passive?

33. Electron Transport Chain
ATP synthase– large protein that creates ATP
Creates ATP by sending the Protons (H+) back across the membrane
What is the concentration gradient?
ATP Synthase in action

35. Electron Transport Chain
4 Carrier Proteins
4 Electrons
2 Electron Carriers
2 FADH or NADH
2 Oxygen
A Lot of Hydrogen!!!