This powerpoint presentation has been adapted from Life 4e-Lewis, Gaffin, Hoefnagels and Parker. Publishers-McGraw-Hill

1. This powerpoint presentation has been adapted from Life 4e-Lewis, Gaffin, Hoefnagels and Parker. Publishers-McGraw-Hill 1998 and Principles of Anatomy and Physiology,Tortora and Grabowski.Publishers- John Wiley & sons, Inc. 2000

2. Chapter 3 Exchanging materials between a cell and its environment

3. Cell (plasma) membrane

4. Cell membrane

5. Parts of the membrane & their functions Phospholipids Bulk of membrane-serves as a selective barrier Cholesterol adds rigidity (only in animal cells) Proteins Some form tunnels that allow certain larger or charged molecules to pass. Receptor sites Carbohydrates with lipids or proteins (glycolipids or glycoproteins) ID the cell

6. What needs to get in & out of cells? IN O2 Nutrients (amino acids, monosaccharides, fatty acids, glycerol, nucleotides, vitamins, minerals, water) OUT CO2 Wastes, toxins products made in the cell, that are intended for other cells/tissues.

7. Molecules that pass through the cell membrane Selectively/Semi permeable- certain molecules, ions can pass through and others can�t What�s difficult? Large Charged Some pass or diffuse without energy (ATP) being used (passive) Small, uncharged small charged ions & large, uncharged molecules Only if have a tunnel (protein molecule embedded in cell membrane)

8. Movement Across Membranes Cell membranes are selectively permeable. Simple diffusion (passive) Substance moves across phospholipids from an area of high to an area of low concentration, without using energy. Substance moves down its concentration gradient (see pg. 82) Ex. O2, H2O, CO2 Selectively permeable - allow some substances to pass through membrane, while preventing others.Selectively permeable - allow some substances to pass through membrane, while preventing others.

9. Simple Diffusion Notice that transport proteins are not involved in simple diffusion. Dynamic equilibrium - point of equal movement back & forth across membrane; no NET movement of molecules.Notice that transport proteins are not involved in simple diffusion. Dynamic equilibrium - point of equal movement back & forth across membrane; no NET movement of molecules.

10. Diffusion of water across membranes is called osmosis. Water is driven to move because the membrane is impermeable to solute(s).

11. Cell: Environment: 1% sucrose 6% sucrose 99% water 94% water Key to figuring this problem out is to remember that in diffusion, substances always move from a higher concentration to a lower concentration. Sucrose would diffuse into the cell if it could; however, the membrane is impermeable to sucrose. Glucose diffuses into the cell until dynamic equilibrium is reached. Fructose is at dynamic equilibrium, so would experience no NET diffusion. Water diffuses out of the cell until dynamic equilibrium is reached. [Water diffuses outward because the solute concentration is greater outside the cell than in the surrounding environment].Key to figuring this problem out is to remember that in diffusion, substances always move from a higher concentration to a lower concentration. Sucrose would diffuse into the cell if it could; however, the membrane is impermeable to sucrose. Glucose diffuses into the cell until dynamic equilibrium is reached. Fructose is at dynamic equilibrium, so would experience no NET diffusion. Water diffuses out of the cell until dynamic equilibrium is reached. [Water diffuses outward because the solute concentration is greater outside the cell than in the surrounding environment].

12. Comparisons of solutions Solute (smaller %) What is being dissolved Solvent (larger %) What is doing the dissolving through a cell membrane, water is usually the most common substance that can cross

13. Tonicity Refers to differences in solute concentration on either side of a semipermeable membrane. Isotonic - both solutions have the same solute (and therefore same solvent) concentrations. (Isosmotic) Hypotonic - solution with the lower solute (and therefore higher solvent) concentration. Hypertonic - solution with the higher solute (and therefore lower solvent) concentration. Solutions are composed of solutes & solvents. solute - substance dissolved in a solution. solvent - the dissolving agent. Most versatile dissolving agent is water.Solutions are composed of solutes & solvents. solute - substance dissolved in a solution. solvent - the dissolving agent. Most versatile dissolving agent is water.

14. What is effect of immersing an animal cell (RBC) in a hypertonic or hypotonic solution? Plasma is normally isotonic to cytoplasm of RBC. Cell is in dynamic equilibrium with plasma & maintains its shape. If RBC is placed in a hypertonic solution, solute concentration is greater in solution than inside the cell. Since RBC membrane is impermeable to solutes, water is driven to move. Thus, water tends to leave the cell to dilute the outside solute. The cell shrinks. If RBC is placed in a hypotonic solution, solute concentration is greater in cytoplasm of RBC. Here again, water is driven to move because the RBC membrane is impermeable to solutes. Thus, water tends to enter the cell. The cell swells & may even burst. Note: Some single-celled protists (paramecium) live in fresh water. They use structures called contractile vacuoles to rid themselves of excess water that is continuously diffusing inward.Plasma is normally isotonic to cytoplasm of RBC. Cell is in dynamic equilibrium with plasma & maintains its shape. If RBC is placed in a hypertonic solution, solute concentration is greater in solution than inside the cell. Since RBC membrane is impermeable to solutes, water is driven to move. Thus, water tends to leave the cell to dilute the outside solute. The cell shrinks. If RBC is placed in a hypotonic solution, solute concentration is greater in cytoplasm of RBC. Here again, water is driven to move because the RBC membrane is impermeable to solutes. Thus, water tends to enter the cell. The cell swells & may even burst. Note: Some single-celled protists (paramecium) live in fresh water. They use structures called contractile vacuoles to rid themselves of excess water that is continuously diffusing inward.

15. What is effect of immersing a plant cell in a hypertonic or hypotonic solution? If plant cell is placed in a hypertonic solution, solute concentration is greater in solution than inside the cell. Since plant cell membrane is impermeable to solutes, water is driven to move. Thus, water tends to leave the cell to dilute the outside solute. The cell shrinks & pulls away from the cell wall. Plant wilts. If plant cell is placed in a hypotonic solution (left), solute concentration is greater in cytoplasm of plant cell. Here again, water is driven to move because the plant cell membrane is impermeable to solutes. Thus, water tends to enter the cell. The cell swells, but will not rupture because of the surrounding cell wall. Plant stands erect. If plant cell is placed in a hypertonic solution, solute concentration is greater in solution than inside the cell. Since plant cell membrane is impermeable to solutes, water is driven to move. Thus, water tends to leave the cell to dilute the outside solute. The cell shrinks & pulls away from the cell wall. Plant wilts. If plant cell is placed in a hypotonic solution (left), solute concentration is greater in cytoplasm of plant cell. Here again, water is driven to move because the plant cell membrane is impermeable to solutes. Thus, water tends to enter the cell. The cell swells, but will not rupture because of the surrounding cell wall. Plant stands erect.

16. Facilitated Diffusion (passive) Substance moves through a transport protein from an area of high to an area of low concentration, without using energy. Substance moves down its concentration gradient Ex. glucose

17. Facilitated Diffusion

18. Active Transport (active) Substance moves through a transport protein from an area of low to an area of high concentration; requires energy (ATP broken/split into ADP and P). Substance moves against its concentration gradient Ex. ions (Na+, K+, Cl-)

19. Active transport

20. Exocytosis &Endocytosis Movement of large particles across membranes with the help of vesicles. Exocytosis - vesicles move particles out of the cell. Exocytosis - vesicle fuses with cell membrane, expelling contents to the outside of the cell. Acrosomal enzymes are found in the head of a sperm. They are released by exocytosis when the sperm encounters an egg. Nerve cells release neurotransmitters by exocytosis. Exocytosis - vesicle fuses with cell membrane, expelling contents to the outside of the cell. Acrosomal enzymes are found in the head of a sperm. They are released by exocytosis when the sperm encounters an egg. Nerve cells release neurotransmitters by exocytosis.

21. Cellular Respiration HEAT glucose + oxygen + water carbon dioxide + water

22. Gas exchange with environment Who needs to do this? All organisms Always needs to occur in a moist environment (cell membranes must be moist). Gas exchange structures Skin lungs gills Other

23. Surface area Increased surface area (SA) -means quicker and more efficient diffusion in/out of cell Reduced volume (vol) of cell- means quicker and more efficient diffusion in/out of cell Large SA/vol = happy cell

24. As a cell enlarges, its volume increases at a faster rate than its surface area. Cells can increase in size only as long as the surface area is large enough to support the volume of the cell. The largest cells in the human body are nerve cells (~ 3 feet in length). They can attain this size only by changing their shape to maximize surface area (are long and thin rather than spherical).As a cell enlarges, its volume increases at a faster rate than its surface area. Cells can increase in size only as long as the surface area is large enough to support the volume of the cell. The largest cells in the human body are nerve cells (~ 3 feet in length). They can attain this size only by changing their shape to maximize surface area (are long and thin rather than spherical).

25. Human respiratory system pg. 90 Nose Passage in. Warms, cleans & moistens the air Trachea Cartilagenous tube Bronchial tubes Trachea splits into each lung (bronchus) Alveoli Where gas exchange between atmosphere and bloodstream occurs. huge surface area (70 m2)

33. p. 195

35. Lung disordersLung cancer - > 90% of lung cancer victims have a history of smoking.

37. Asthma 

38. Emphysema

39. Go to pg.87-88

40. Countercurrent Exchange

41. Fish blood circulation

42. Fish blood circulation

43. Gas exchange through gills Water has 20x less O2 than atmosphere Gills SA Filaments

46. Getting rid of wastes Nitrogenous wastes- when proteins & NA are used for cellular respiration the Amino part must first be removed. Deamination. Deamination-Done by liver Ammonia- water dwellers. Very easy to make. Very TOXIC, must be heavily diluted. Urea- Harder to make. Less TOXIC, must be somewhat diluted. Most mammals. Uric acid- Very difficult to make. Not TOXIC, requires no water for dilution. Egg layers.

51. The urinary system Kidneys- filter nitrogenous wastes from blood and dilutes with water = urine. Functional part is called the nephron Ureters 8-10� tubes to bladder Urinary bladder Can hold 2 cups urine for 2-5 hrs. Urethra- sphincter 2-4� tube to outside