Cell/Plasma Membrane

1. Cell Transport • Cell/Plasma Membrane • Regulates what enters and leaves the cell and provides protection and support. • Phospholipid Bilayer • Selectively Permeable

3. Cell Membrane Model • Cell/Plasma Membrane • FIRST color the phospholipid bilayer! • Blue – phosphate heads • Red – lipid tails • Purple - protein

4. Cell Transport • Passive Transport – when the cell does not require energy to move molecules across a membrane. • Movement from high to low concentration (conc.)

5. Passive Transport Particle movement from an area of high concentration to an area of low concentration. Equilibrium – when the concentration of the solute is the same throughout a system.

6. Hot Water Cold Water Room Temp. Water • How does temperature affect diffusion? • Why is a warm body advantageous to a living thing?

7. Passive Transport

8. Passive Transport The diffusion of water through a selectively permeable membrane. • Isotonic – The concentration of solutes is the same inside and outside the cell • Hypotonic – solution has a lower solute concentration than the cell. • Hypertonic – solution has a higher concentration of solute than the cell

10. Passive Transport

11. Gummy Bear Lab

14. Passive Transport Movement of specific molecules across cell membranes through protein channels Protein channel – act as “doorways” for larger molecules, and allow certain molecules to cross membrane

15. Passive Transport • Red blood cells have a cell membrane protein that allows glucose to pass through it. • Does not need energy!

16. Active Transport • Active Transport – energy-requiring process that moves material across a cell membrane against a concentration difference.

17. Active Transport When small molecules and ions are carried across membranes by proteins in the membrane that act like energy-requiring pumps Needs ENERGY! Moves from low concentration to high concentration

18. Active Transport • Many cells move calcium, potassium, and sodium across cell membranes

19. Active Transport • Process of taking material into the cell by means of infoldings, or pockets, of the cell membrane • Phagocytosis – “cell eating” extensions of cytoplasm surround and engulf large particles and take them into the cell • Pinocytosis – cell takes in liquid from the surrounding environment

21. Active Transport

22. Gummy Bear Lab Day 2

23. Active Transport • Process by which a cell releases large amounts of material

24. Active Transport • Cell can get rid of waste or cellular materials this way

25. Determine passive vs. active; give specific type • A cell membrane encloses and takes in a drop of fluid. • Carrier proteins use energy and act as a pump to move nutrients into a root cell. • Carrier proteins take sugar (glucose) into a cell without requiring energy input. • Water diffuses across a cell membrane from a region of high concentration to a region of low concentration. • Mucus and waste products packaged by Golgi apparatus are secreted by a cell. • A cell membrane encloses and takes in large food particles.

26. Passive or active?

27. Passive or active?

28. Passive or active?

29. Amoeba Food particle Passive or active?

30. Passive or active?

31. Passive or active?

32. Gummy Bear Lab Day 3

33. Plasmolysis • Obtain a piece of red onion, slide and cover slip. • Create a wet mount slide with water. • Observe the appearance of the cells under the microscope. • Use toweling method to add several drops of salt water. • Observe the appearance of the cells under the microscope. • What happened? • Why?

34. Before Salt Water After Salt Water