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Structure (Plasma Membrane) A lipid bilayer(2 layers of lipids) with a variety of proteins.

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Presentation on theme: "Structure (Plasma Membrane) A lipid bilayer(2 layers of lipids) with a variety of proteins."— Presentation transcript:


2 Structure (Plasma Membrane) A lipid bilayer(2 layers of lipids) with a variety of proteins

3 Lipid molecule Proteins

4 Identify the lipid molecules. Identify the protein molecules. What is a ‘lipid bilayer’?

5 Function - To be Selective Permeable: = control what passes in or out of the cell (Plasma Membrane) -Helps maintain Homeostasis: = maintain a stable internal environment

6 - Act as a lining, separates the chemicals of the cytoplasm from the surroundings What the lipids do…

7 (Plasma Membrane). 1. Form a. open channels b. gated channels c. active transport pathways, All to move molecules in & out of the cell! What the proteins do…


9 Open channels Ex. 1 of channel proteins.


11 Gated channel Ex. 2 of channel proteins.



14 (Plasma Membrane) - - Receptors that change cellular activity. Protein Function #2

15 Receptor protein Signal molecule

16 Change cellular activity

17 (Plasma Membrane) - - Create a molecular mark (signature) that identifies that specific, individual cell. Protein Function #3

18 Recognition protein

19 LOOK!

20 Types of particle that might cross membranes. Tiny molecules, like… Water Oxygen & Carbon dioxide

21 Types of particle that might cross membranes. Small molecules, like… Glucose, amino acids, fatty acids and glycerol

22 Water Carbon Dioxide Oxygen Aminoacid Glycerol Glucose Fatty Acid

23 Yet more types of particles that might cross cell membranes! Yes, even large molecules, such as… Polysaccharides Lipids & proteins!

24 Lipid soluble molecules Fats, Fatty acids

25 Charged particles ions Na+, K +, Cl +

26 Even Large Particles may sometimes cross the selectively permeable cell membrane! Such as… small organisms and Organic debris

27 Diffusion Movement of particles from an area of high concentration to an area of lower concentration.

28 Diffusion requires a Diffusion requires a Concentration gradient When the concentration of particles is not the same throughout a mixture.

29 Concentration Gradient There is a region of high concentration and a region of low concentration.

30 Go to page 7 in the note packet and learn about the use of square brackets. [ ]

31 Do the activity The Tea Cup & The Swimming Pool on page 8.


33 Equilibrium When the concentration of particles is the same throughout a mixture.

34 Equilibrium There is no region of high, nor a region of low concentration of particles.

35 Equilibrium All particle continue to move.

36 DiffusionConcentrationgradient Equilibrium

37 TRANSPORT The Movement of Materials Across Membranes

38 Passive Transport Materials move down the concentration gradient and across a membrane.

39 What determines if a particle can go through a channel?

40 Dialysis Tubing


42 Osmosis The passive transport of water across a membrane.

43 Thistle Tube Demo

44 water molasses thistle tube Selectively permeable membrane






50 Active Transport Particles move Across a SPM. theAgainst the concentration gradient. The cells must spend energy.

51 Active transport allows particles to move against the concentration gradient. (from an area of _____ concentration to an area of ___ concentration) HIGH LOW

52 An example of Active Transport: All animal cells have a Sodium Potassium pump that pumps sodium (Na +) to the outside of cells and potassium (K +) to the inside of cells.

53 This ‘pump’ allows nerve cells to carry electrical messages through the body! Nerve cell

54 The Cell Membrane of a nerve cell

55 Endocytosis Particles move INTO the cell by folding a portion of the membrane around a particle, resulting in a vesicle.

56 There are two types of Endocytosis: Pinocytosis - drinking Dissolved materials Phagocytosis - eating Food particles



59 Pinocytosis The solute particles are too small to see but too big to pass through the membrane.

60 Exocytosis Particles move OUT OF a cell by fusing vesicles with the cell membrane.


62 Maintaining water balance in Protists




66 Facilitated Transport (Facilitated Diffusion) -Diffusion using protein channels


68 Transport protein


70 Gated channel




74 The End

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