2. The Cell Membrane & Cellular Transport Function of cell membrane Structure of cell membrane Cellular transport

3. All living cells must maintain a balanced environment regardless of internal and external conditions. This process of maintaining the cell’s environment (balance) is called homeostasis. Survival depends on the cell’s ability to maintain the proper conditions within itself. Introduction

4. I. Functions of the cell Membrane B.Control what goes in and out of the cell. 1)Selective permeability (Semipermeable) describes the cell membrane’s ability to allow some molecules into the cell while keeping others out. Water Cell Membrane

5. allow waste and other products to leave the cell. remove excess amounts of these nutrients when levels get so high that they are harmful. a)allow a steady supply of water, glucose, amino acids, and lipids to come into the cell no matter what the external conditions are. C.Maintain homeostasis I. Functions of the Cell Membrane

6. II. Structure of the Cell Membrane A.The cell membrane is composed of 2 layers of phospholipids back- to-back. Phospholipids are lipids with a phosphate attached to them. The two layers are referred to as the phospholipid bilayer.

7. B.The lipid units that make up the plasma membrane have a: 1.glycerol backbone 2.two fatty acid chains, and 3.A phosphate group. Glycerol Backbone Two Fatty Acid Chains Phosphate Group II. Structure of the Plasma Membrane

8. Which of the following best describes the cell membrane's mechanism in maintaining homeostasis? A protein synthesis B selective permeability C fluid composition D structural protein attachment Question 1

9. The answer is B. Selective permeability is the process in which the membrane allows some molecules to pass through, while keeping others out.

10. Cellular Transport Passive Transport Active Transport

11. Types of Cellular Transport Passive Transport cell DOES NOT use energy 1. Diffusion 2. Facilitated Diffusion 3. Osmosis Active Transport cell DOES use energy 1. Protein Pumps 2. Endocytosis 3. Exocytosis high low This is gonna be hard work!! high low Weeee! !! Animations of Active Transport & Passive TransportAnimations

12. II. Passive Transport A.[HIGH] concentration  [LOW) concentration B.NO energy required C.3 types of passive transport HIGH LOW

13. 3 Types of Passive Transport 1. Diffusion – movement of molecules across the cell membrane 2. Facilitative Diffusion – diffusion with the help of transport proteins 3. Osmosis – diffusion of water

15. Animation : How Diffusion Works

16. 2.Facilitated Diffusion type of passive transport which uses the help of transport proteins.

17. Animation - How Facilitated Diffusion Works

18. Glucose Absorption - Diabetes

19. 3.Osmosis Osmosis water a)The diffusion of water across selectively permeable membranes. b)The water moves from a [high]  [low] concentration. http://www.bbc.co.uk/education/asguru/biology/01cellbiology/05pathways/10osmosis/index.shtml (p. 186)

20. Animation: How Osmosis Works

21. Question: What’s in a Solution? Answer: solute+ solvent  solution NaCl (salt)+ H 2 0  saltwater

22. 1)Hypertonic solution A solution with a greater solute concentration compared to another solution. 5% NaCl 95% H 2 O solution 3% NaCl 97% H 2 O Red Blood Cell c)Osmosis c)Osmosis occurs in 3 types of solutions. Water moves OUT!

23. 2)Hypotonic solution A solution with a lower solute concentration compared to another solution. 3% Na 97% H 2 O Red Blood Cell 1% Na 99% H 2 O solution c)Osmosis c)Osmosis occurs in 3 types of solutions. Water moves IN!

24. 3)Isotonic solution A solution with an equal solute concentration compared to another solution. 3% Na 97% H 2 O Red Blood Cell 3% Na 97% H 2 O solution c)Osmosis c)Osmosis occurs in 3 types of solutions. Water moves IN & OUT @ same rate!

25. Animation-Diffusion - Hypotonic, Isotonic, Hypertonic

26. Hypotonic  Hypertonic What happens to blood cells placed in various solutions? Swell & burst Stay the same Shrivel

27. f.Osmosis in Plant Cells

28. III. Active Transport A.Molecules (large or small) move against concentration gradient B.[LOW]  [HIGH] C.requires energy (ATP = unit of energy used by living things) D.Three types: HIGH LOW

29. Types of Active Transport 1. Protein Pumps - transport proteins that require energy to do work Example: Sodium / Potassium Pumps are important in nerve responses. Sodium Potassium Pumps Sodium Potassium Pumps (Active Transport using proteins) Protein changes shape to move molecules: this requires energy!

30. Animation How the Sodium-Potassium Pump Works

31. Types of Active Transport 2. Endocytosis: taking bulky material into a cell Uses energy Cell membrane in-folds around food particle “cell eating” forms food vacuole & digests food This is how white blood cells eat bacteria!

32. Types of Active Transport 3. Exocytosis: Forces material out of cell in bulk membrane surrounding the material fuses with cell membrane Cell changes shape – requires energy EX: Hormones or wastes released from cell Endocytosis & Exocytosis Endocytosis & Exocytosis animations