Cell transport

1. Cell transport

2. So… We talked about digestion • After the polymers get broken down into monomers and they travel through the digestive system…..What happens to these molecules after they are absorbed? • Where do these molecules go? Into our cells

3. esophogus stomach small intestine

4. Cell transport • Every organism is made of specialized cells (Red blood cells, muscle cells, nerve cells) • Each cell must perform an important life function • The cell membrane is important. Extremely

5. This is where homeostasis comes to play

6. Have you ever wondered why your dog pants on hot days? It's because your dog is trying to maintain homeostasis. Homeostasis is a word used to describe how a living organism regulates its internal environment to maintain stability (equilibrium = balance).

7. How does homeostasis work? • One very important part of homeostasis is body temperature. On any particular day, the temperature might change by as much as 50º. In order for an organism's chemical reactions to continue as they should, the temperature on the inside of the organism needs to remain the same. equilibrium

8. How do living things maintain homeostasis?When your body temperature begins to rise, what happens? *You begin to sweat. *Sweating is your body's way of cooling down = Homeostasis

9. Dogs….. • do not have sweat glands SO they pant. • Dogs have just a few sweat glands in their paws, so no matter how much they sweat; sweating could never cool them off. • That's where the tongue-hanging out, mouth-open dog panting comes in.

10. The cell membrane is what allows all this to occur • The cell membrane controls what goes in and out of the cell and maintains homeostasis • You can't have molecules go in and out of the cell without any barrier. • The cell membrane provides this barrier.

11. Cell Membrane • The cell membrane regulates what enters and leaves the cell (body guard) • It is made of a double layer sheet called a phospholipid bilayer • It is semi permeable • It is also known as the fluid mosaic model

12. Cell Membrane Structure

13. Carbohydrate chains Proteins Protein channel Lipid bilayer What controls what goes in or out of the cell membrane? • Proteins move material across the cell membrane Carbohydrates (glucose) Proteins(peripheral and integral) Phospholipids

14. What molecules are the cell membrane composed of? * Proteins – Aid in transport *are chemical receptors * Phospholipids – double layer of proteins & lipids * Cholesterol – helps keep the phospholipids spaced apart *Surface carbohydrates – allow for cell recognition & signaling

15. Cell membrane is known as the fluid mosaic model b/c: FLUID- because individual phospholipids and proteins can move around freely within the layer, like it’s a liquid. MOSAIC- because of the pattern produced by the scattered protein molecules when the membrane is viewed from above.

16. Part II Types of Transport Across Cell Membranes

17. Transport of molecules such as water, oxygen, glucose into and out of the cell

18. Diffusion High to Low • Requires NO energy • Molecules move from area of HIGH to LOW concentration

19. DIFFUSION Diffusion is a PASSIVE process which means no energy is used to make the molecules move

20. Glucose High Concentration Cell Membrane Protein channel Low Concentration

21. Diffusion of Liquids

22. Passive Transport • Simple Diffusion • Doesn’t require energy • Moves high to low concentration • Example: Oxygen or water diffusing into a cell and carbon dioxide diffusing out.

23. Part IIIOsmosis

24. Osmosis • Diffusion of wateracross a membrane • Moves fromHIGH water potential(low solute) toLOW water potential(high solute) Diffusion across a membrane Semipermeable membrane

25. Diffusion of H2O Across A Membrane High H2O potentialLow solute concentration Low H2O potentialHigh solute concentration

26. Solute + Solvent = Solution • Solute (6 letters) :a substance dissolved in solvent, forming a solution • Solvent (7 letters) :is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution • Solution (8 letters)

27. Cell in Isotonic Solution 10% NaCL90% H2O ENVIRONMENT CELL NO NET MOVEMENT 10% NaCL 90% H2O What is the direction of water movement? equilibrium The cell is at _______________.

28. Cell in Hypotonic Solution Water moves into the cell 10% NaCL90% H2O CELL 20% NaCL 80% H2O What is the direction of water movement?

29. Cell in Hypertonic Solution 15% NaCL85% H2O ENVIRONMENT CELL 5% NaCL 95% H2O Water moves out of the cell What is the direction of water movement?

30. Osmosis in Red Blood Cells Isotonic Hypertonic Hypotonic

31. hypotonic hypertonic isotonic hypertonic isotonic hypotonic

32. Transport of Large molecule

33. Facilitated Diffusion Molecules will randomly move through theporesinChannel Proteins.

34. Facilitated Diffusion • Some Carrier proteins do not extend through the membrane. • They bond and drag molecules through the lipid bilayer and release them on the opposite side.

35. Active Transport • Requires energy or ATP • Moves materials from LOW to HIGH concentration • AGAINST concentration gradient

36. Moving the “Big Stuff” Exocytosis- moving things out. Molecules aremoved outof the cell byvesicles that fusewith the plasma membrane. This is how manyhormonesare secreted and hownerve cellscommunicate with one another.

37. Exocytosis Exocytic vesicle immediately after fusion with plasma membrane.

38. Moving the “Big Stuff” Large molecules move materials into the cell by one ofthree forms of endocytosis.

39. Endocytosis – Phagocytosis Used toengulf large particlessuch as food,bacteria, etc. into vesicles Called“Cell Eating”

40. Phagocytosis- Captureof aYeastCell (yellow) by Membrane Extensions of anImmune System Cell(blue)