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Types of Transport Across Cell Membranes 1. Passive Transport.

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Presentation on theme: "Types of Transport Across Cell Membranes 1. Passive Transport."— Presentation transcript:

1 Types of Transport Across Cell Membranes 1

2 Passive Transport

3 Simple Diffusion Requires NO energy Molecules move from area of HIGH to LOW concentration 3

4 Simple Diffusion 4  no energy is used to make the molecules move because they have a natural KINETIC ENERGY

5 Diffusion of Liquids 5

6 Diffusion through a Membrane 6 Cell membrane Solute moves DOWN concentration gradient (HIGH to LOW)

7 Diffusion Animation Movement of particles from an area of  concentration to an area of  concentration.

8 Osmosis Diffusion of water across a membrane Moves from HIGH water potential (low solute) to LOW water potential (high solute) No Energy needed 8 Diffusion across a membrane Semipermeable membrane

9 Diffusion of H 2 O Across A Membrane 9 High H 2 O potential Low solute concentration Low H 2 O potential High solute concentration

10 Osmosis Net diffusion of H 2 0 across a semi permeable membrane


12 Isotonic Concentration of solute is equal on both sides of the membrane No water net water movement

13 Hypotonic Solute concentration is less outside the cell  Therefore more water outside the cell Water moves into the cell  CYTOLYSIS (blows up)

14 Hypertonic Solute concentration is greater outside the cell  Therefore more water inside the cell Water moves out of the cell  PLASMOLYSIS (shrivels)

15 Cell in Isotonic Solution 15 CELL 10% NaCL 90% H 2 O 10% NaCL 90% H 2 O What is the direction of water movement? The cell is at _______________. equilibrium ENVIRONMENT NO NET MOVEMENT

16 Cell in Hypotonic Solution 16 CELL 10% NaCL 90% H 2 O 20% NaCL 80% H 2 O What is the direction of water movement?

17 Cell in Hypertonic Solution 17 CELL 15% NaCL 85% H 2 O 5% NaCL 95% H 2 O What is the direction of water movement? ENVIRONMENT

18 18 Isotonic Solution NO NET MOVEMENT OF H 2 O (equal amounts entering & leaving) Hypotonic Solution CYTOLYSIS Hypertonic Solution PLASMOLYSIS

19 Cytolysis & Plasmolysis 19 Cytolysis Plasmolysis

20 Osmosis in Red Blood Cells 20 Isotonic Hypotonic Hypertonic

21 Transport with Proteins

22 Types of Transport Proteins 22 Channel proteins are have a pore for materials to cross Carrier proteins can change shape to move material

23 23 Transport with Proteins

24 24 Facilitated Diffusion Doesn’t require energy  Uses transport proteins to move substances from high to low concentration Examples: Glucose or amino acids moving from blood into a cell.

25 Facilitated Diffusion Carrier protein helps diffusion occur (no energy)

26 Active Transport

27 27 Active Transport  Requires energy or ATP  Moves materials from LOW to HIGH concentration  AGAINST concentration gradient

28 Active Transport Use energy (ATP) to move particles against the concentration gradient.

29 Active transport  Examples: Pumping Na + (sodium ions) out and K + (potassium ions) in against strong concentration gradients.  Called Na+-K+ Pump 29

30 Moving “Big” Stuff

31 Endo or Exocytosis Endocytosis  Intake Exocytosis  Export Both move large molecules through the creation of vessicles.

32 32 Excocytosis – Move Out Molecules are moved out of the cell by vesicles that fuse with the plasma membrane. This is how many hormones are secreted and how nerve cells communicate with one another.

33 33 Exocytosis Exocytic vesicle immediately after fusion with plasma membrane.

34 34 Endocytosis – Move in Large molecules move materials into the cell by one of two forms of endocytosis.

35 35 Pinocytosis – cell drinking Most common form of endocytosis. Takes in dissolved molecules as a vesicle.

36 Pinocytosis Cell forms an invagination Materials dissolve in water to be brought into cell Called “Cell Drinking” 36

37 37 Phagocytosis – Cells Eating Used to engulf large particles such as food, bacteria, etc. into vesicles Called “Cell Eating”

38 38 Phagocytosis About to Occur

39 39 Phagocytosis - Capture of a Yeast Cell (yellow) by Membrane Extensions of an Immune System Cell (blue)

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