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Cell Membrane

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Cell Membrane Outside of cell Carbohydrate chains Proteins Cell membrane Inside of cell (cytoplasm) Protein channel Lipid bilayer – PowerPoint PPT presentation

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Title: Cell Membrane


1
Cell Membrane
2
TEKS Science Concepts
  • 4 -The student knows that cells are the basic
    structures of all living things and have
    specialized parts that perform specific
    functions, and that viruses are different from
    cells and have different properties and
    functions. The student is expected t
  • (B) investigate and identify cellular processes
    including homeostasis, permeability, energy
    production, transportation of molecules, disposal
    of wastes, function of cellular parts, and
    synthesis of new molecules

3
Membrane structure
  • Semi-Permeable
  • Selectively Permeable
  • Amphipathic hydrophobic hydrophilic
    regions
  • Fluid Mosaic Model

4
The Structure of the Cell Membrane
5
Membrane structure
  • Phospholipids membrane fluidity
  • Cholesterol membrane stabilization and fluidity
  • Integral proteins transmembrane proteins
  • Peripheral proteins surface of membrane proteins
  • Membrane carbohydrates cell to cell
    recognition

6
Video 1
7
Random movement results in
  • Solution mixture of solute and solvent
  • Solute substance being dissolved
  • Solvent substance dissolving solute
  • Living Things (Universal Solvent)-Water

8
Membrane traffic
  • Passive transport diffusion of a substance
    across a biological membrane (NO ENERGY)
  • concentration
  • Diffusion the overall movement of particles from
    a region of high to an area of low
  • Osmosis the diffusion of water across a
    selectively permeable membrane

9
Results of Diffusion
  • Dynamic equilibrium
  • Once diffusion has evenly distributed the solute
    throughout the solvent movement of particles
    continues with no change in
  • Homeostasis
  • Preservation of equilibrium

10
Diffusion depends on gradient
  • gradient the difference in of a substance
    across space
  • Diffusion is said to move down a gradient
  • Diffusion continues until there is NO gradient
  • Ex O2 diffuses into oxygen depleted blood

11
Diffusion
  • Small molecules like WATER, OXYGEN, AND CARBON
    DIOXIDE can move in and out freely.
  • Large molecules like PROTEINS AND CARBOHYDRATES
    CANNOT
  • Charged IONS CANNOT

12
Video 2
Osmosis
13
Osmosis the diffusion of water across a
selectively permeable membrane
14
Questions
  • Osmosis is the diffusion of _______ across a cell
    membrane.
  • Osmosis and Diffusion are both types of
    __________ transport.
  • Passive transport does or does not require
    energy?
  • Small molecules can not move across freely. T or
    F
  • Large molecules can move freely. T or F

15
Three Different Types of Solutions
  • Isotonic Solution
  • Hypotonic Solution
  • Hypertonic Solution

16
Isotonic Solution
  • The solute outside the cell is equal in
    concentration to the solute in the cell.
  • The cell retains its shape.
  • water moves equally in both directions

17
Hypotonic Solutions
  • Solution outside the blood cell contains a lower
    of solute than inside of the cell.
  • Water will diffuse in.
  • cell will lyse (burst).
  • Animal cells - cytolysis.
  • Plant cells do not burst- turgur pressure
    grocers use this idea

18
Cells in a Hypotonic Solution
19
Hypertonic Solutions
  • The solution outside the cell has a higher of
    solute than inside of the cell.
  • Water will diffuse out of the cell,
  • causing the cell to shrink
  • or crenate
  • Why should you not salt meat before
    cooking? CRENATION PLASMOLYSIS

20
Cells in a Hypertonic Solution
21
In what type of solution would these cells be
found?
22
Water balance Summary
  • Osmoregulation control of water balance
  • Hypertonic higher concentration of solutes
  • Hypotonic lower concentration of solutes
  • Isotonic equal concentrations of solutes

23
Water balance Summary
  • Osmoregulation control in cells with cell
    walls
  • Turgid (very firm) - Hypo
  • Flaccid (limp) - Iso
  • Plasmolysis Hyper
  • plasma membrane pulls away from cell wall

24
Plasmolysis Turgidity
25
Other Ways to Transport Molecules Across the
Plasma Membrane
  • Selective Transport

26
Review Covered Passive Transport
  • Osmosis
  • Does it require energy?
  • NO!!!
  • Diffusion
  • Does it require energy?
  • NO!!!

27
Osmosis
  • What is osmosis?
  • The movement of ___________ across the cell
    membrane.
  • Is it the movement of any other substance?
  • NO!!!!

WATER
28
Diffusion
  • Mixing of two substances by the random motion of
    molecules.
  • Molecules move from a region of high
    concentration to an area of low concentration.

29
How do other molecules cross the cell membrane???
  • Selective Transport
  • Facilitated Diffusion (Another Passive Transport)
  • Active Transport
  • Protein Pumps
  • Endocytosis
  • Exocytosis

30
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31
Selective Transport
  • There are two types of selective transport
  • Facilitated Diffusion
  • DOES NOT require the use of energy
  • Active Transport
  • DOES require the use of energy

32
Facilitated Diffusion
Glucose molecules
High Concentration
Cell Membrane
Low Concentration
Protein channel
33
Facilitated Diffusion
  • Does facilitated diffusion require the use of
    energy?
  • NO!!!!
  • It uses a gradient to transport molecules
  • The molecules move from an area of high to an
    area of low
  • Most SUGAR molecules pass across the cell
    membrane by this method of transport

34
Carrier Proteins Carry Molecules Across the
Membrane
  • Good Example - transport of Glucose into the Cell

35
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36
Active Transport
  • Does active transport require the use of energy?
  • YES!!!
  • It uses ATP
  • Transports against the gradient.
  • Low to High
  • Sodium Potassium Pump, Endocytosis and Exocytosis

37
Active Transport
38
Active Transport Sodium Potassium Pump
  • Move Sodium out of the cell
  • Move Potassium into the cell
  • Uses energy (ATP)
  • Causes the protein to change shape
  • Move against a gradient

39
Sodium Potassium Pump
40
Bulk Transport-Active
  • Endocytosis
  • Pinocytosis
  • Phagocytosis
  • Exocytosis

41
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42
Endocytosis
  • During ENDOCYTOSIS the Cell Membrane folds into a
    POUCH (Vescicle) that Encloses the Particles.

43
Two Types of Endocytosis Pinocytosis and
Phagocytosis
  • PINOCYTOSIS ---"CELL DRINKINGSmall Particles
  • PHAGOCYTOSIS---- "CELL EATING-Large Particles

44
Treatments
45
Exocytosis
  • EXOCYTOSIS is the opposite OR reverse of
    ENDOCYTOSIS.
  • EXOCYTOSIS, wastes and cell products leave the
    cell.

46
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47
Specialized Transport Summary
  • Transport proteins
  • Facilitated diffusion passage of molecules and
    ions with transport proteins across a membrane
    down the gradient
  • Active transport movement of a substance against
    its gradient with the help of cellular energy

48
Elaborate
  • Cell Membrane Bubbles
  • Cellular Transport Flow Chart
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