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Chapter 8 – Cellular Transport Plasma Membrane Selectively permeable Controls what passes through the membrane Made of: phospholipids, proteins, and.

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Presentation on theme: "Chapter 8 – Cellular Transport Plasma Membrane Selectively permeable Controls what passes through the membrane Made of: phospholipids, proteins, and."— Presentation transcript:

1

2 Chapter 8 – Cellular Transport

3 Plasma Membrane Selectively permeable Controls what passes through the membrane Made of: phospholipids, proteins, and cholesterol.

4 Diffusion Movement of molecules from a high concentration of molecules to a low concentration of molecules Brownian movement: molecules are moving all the time- (random movement)

5 Concentration Gradient Difference in the concentration of molecules across a space Molecules will move until the solute and solvent are mixed evenly

6 Dynamic Equilibrium When the concentration of the molecules are equally distributed There is no concentration gradient There will still be movement of particles, but no net change

7 Osmosis Diffusion of water molecules through a selectively permeable membrane (type of diffusion) High concentration to….. Low concentration

8 Osmosis: Diffusion of Water Regulating the water flow through the plasma membrane is an important factor in maintaining homeostasis within a cell.

9 Section 8.1 Summary – pages Unequal distribution of particles, called a concentration gradient, is one factor that controls osmosis. What controls osmosis? Before Osmosis After Osmosis Water molecule Sugar molecule Selectively permeable membrane

10 3 type of solutions Isotonic Solution Hypertonic Solution Hypotonic Solution

11 Section 8.1 Summary – pages Cells in an isotonic solution In an isotonic solution, the concentration of dissolved substances in the solution is the same as the concentration of dissolved substances inside the cell. H2OH2O H2OH2O Water Molecule Dissolved Molecule

12 This means: The concentration of the water is the same inside the cell and outside the cell Dynamic Equilibrium has been reached

13 Cells in an isotonic solution In an isotonic solution, water molecules move into and out of the cell at the same rate, and cells retain their normal shape. H2OH2O H2OH2O Water Molecule Dissolved Molecule

14 Section 8.1 Summary – pages Cells in an isotonic solution A plant cell has its normal shape and pressure in an isotonic solution.

15 Cells in a hypertonic solution In a hypertonic solution, there is a higher concentration of dissolved substances (solute) in the solution than the concentration inside the cell

16 This means……. The water concentration is lower outside the cell than inside the cell

17 Section 8.1 Summary – pages Cells in a hypertonic solution In a hypertonic solution, water leaves a cell by osmosis, causing the cell to shrink. H2OH2O H2OH2O Water Molecule Dissolved Molecule

18 Cells in a hypertonic solution Plant cells lose pressure as the plasma membrane shrinks away from the cell wall.

19 Cells in a hypotonic solution In a hypotonic solution, there is a lower concentration of dissolved substances (solute) in the solution than inside the cell

20 This means….. Water concentration is higher outside the cell than inside the cell

21 Cells in a hypotonic solution In a hypotonic solution, water enters a cell by osmosis, causing the cell to swell. H2OH2O H2OH2O Water Molecule Dissolved Molecule

22 Section 8.1 Summary – pages Cells in a hypotonic solution Plant cells swell beyond their normal size as pressure increases.

23 Blood cell Plant cell

24 Review Hypotonic solution-hippo/hypo Water enters his mouth- looks like he is going to explode

25 Review Hyper kids rushing out of class after 2 hours in 104 degree classroom Hyper-Hypertonic- water leaves the cell

26 Types of Transport Passive Transport Active Transport

27 Passive Transport Movement of particles across membranes by diffusion - the cell uses NO energy to move the particles - particles move ALONG the concentration gradient

28 Passive Transport Diffusion Osmosis Facilitated Diffusion High Concentration to Low Concentration

29 Facilitated Diffusion Type of passive transport that uses transport proteins Doesnt use energy

30 Active Transport Transport that requires energy Transport of materials AGAINST the concentration gradient High Concentration Low Concentration

31 Active Transport Endocytosis Exocytosis

32 Endocytosis Phagocytosis- cell engulfs particle with pseudopodia (cell eating) Pinocytosis-cell gulps/drinks extracellular fluid (cell drinking)

33 Section 8.1 Summary – pages Transport of Large Particles Endocytosis is a process by which a cell surrounds and takes in material from its environment. Endocytosis Exocytosis Digestion Nucleus Wastes

34 Section 8.1 Summary – pages Transport of Large Particles The material is engulfed and enclosed by a portion of the cells plasma membrane. Exocytosis Digestion Nucleus Wastes Endocytosis

35 Section 8.1 Summary – pages Transport of Large Particles The resulting vacuole with its contents moves to the inside of the cell. Exocytosis Digestion Nucleus Wastes Endocytosis

36 Section 8.1 Summary – pages Transport of Large Particles Exocytosis is the expulsion or secretion of materials from a cell. Endocytosis Exocytosis Digestion Nucleus Wastes

37 Transport of Large Particles Endocytosis and exocytosis both move masses of material and both require energy. EndocytosisExocytosis Digestion Nucleus Wastes

38 Section 1 Check Question 1 B. endocytosis A. active transport The diffusion of water across a selectively permeable membrane is called __________. Water molecule Sugar molecule Selectively permeable membrane

39 Section 1 Check Question 1 D. osmosis C. exocytosis The diffusion of water across a selectively permeable membrane is called __________. Water molecule Sugar molecule Selectively permeable membrane

40 Section 1 Check The answer is D, osmosis. Regulating the water flow through the plasma membrane is an important factor in maintaining homeostasis within the cell. Water molecule Sugar molecule Selectively permeable membrane Before osmosisAfter osmosis

41 Section 1 Check What is the expected result of having an animal cell in a hypertonic solution? Question 2 D. The cell retains its normal shape. C. The cell swells up. A. The cell shrivels up. B. The plasma membrane shrinks away from the cell wall.

42 Section 1 Check The answer is A. In a hypertonic solution, cells experience osmosis of water out of the cell. Animal cells shrivel because of decreased pressure in the cells. H2OH2O H2OH2O Water molecule Sugar molecule

43 Section 1 Check A grocer mists the celery display with water to keep it looking fresh. What type of solution is the celery now in? Question 3 D. exotonic C. hypertonic B. hypotonic A. isotonic

44 Section 1 Check The answer is B. Plant cells contain a rigid cell wall and do not burst even in a hypotonic solution.

45 Plasma membrane Section 1 Check Transport of materials across the plasma membrane that does not require energy from the cell but does use transport proteins is called __________. Question 4 B. simple diffusion A. osmosis Concentration gradient Channel proteins

46 Section 1 Check Transport of materials across the plasma membrane that does not require energy from the cell but does use transport proteins is called __________. Question 4 D. active transport C. facilitated diffusion Plasma membrane Concentration gradient Channel proteins

47 Section 1 Check The answer is C. Facilitated diffusion is a type of passive transport and requires no energy from the cell. Plasma membrane Concentration gradient Channel proteins

48 End of Chapter 8 Show


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