Fluid Mosaic Model Current model of the membrane
Fluid Mosaic Model • Current model of the membrane structure. • Phospholipids fluid sea in embedded with a wide variety of protein molecules.
Cell Membrane • The cell membrane is also known as: –Phospholipids bi-layer –Plasma membrane –Fluid mosaic membrane
What is a Solution? • Is a homogeneous mixture • A combination of a Solute and Solvent. • Large part is the solvent (water) • Small part is the solute
![What is a [ ] Gradient? • Is the process of particles, which the](http://slidetodoc.com/presentation_image_h/990625eb6deb2704a6e2aeec9c136691/image-6.jpg "What is a [ ] Gradient? • Is the process of particles, which the")
What is a [ ] Gradient? • Is the process of particles, which the solutes is moving through a solution from an area of higher number of particles to an area of lower number of particles. [ High ] to [Low]
Concentration Gradient High Down Low
Protein Carrier molecule
What can diffuse through? • Small & nonpolar molecules can diffuse through the cell membrane • CO 2 • O 2
Understanding solutions • More Solvent • Less Solute • Less solvent • More Solute solvent
Understanding solutions Hypotonic solution Hypertonic Solution solute solvent
Understanding solutions • Hypotonic Solution • Hypertonic solution Cell solute solvent
Understanding solutions • The solution has solvent and solute • The cell has solvent and solute too. solute
Who has more solute? 25% solute 75% solute What type of solution is this cell in?
What will happen to this cell? H 2 O Cell Shrinks
Who has more solute? 85% solute 15% solute What type of solution is this cell in?
Lysis H 2 O Cell Swells or burst
Who has more solute? 40% solute What type of solution is this cell in?
Isotonic solution 60% water 40% solute 60% water The cell stays the same
Hypertonic Solution Plant Cells Animal Cells
Hydrophobic vs Hydrophilic • Hydrophilic (attracted to water) • Hydrophobic (not attracted to water but are attracted to other hydrophobic tails) • They have a hydrophilic phosphate head and two hydrophobic hydrocarbon tails. • Cell membranes are made up of a double layer of these phospholipid molecules. • The phospholipid bilayer makes the membrane very stable but also allows flexibility. • The phospholipid in the membrane are in a fluid state which allows the cell to change it’s shape easily.
Osmotic Pressure • The pressure of water moving across a membranes cause by a concentration gradient.
Turgor Pressure • Is a hydrostatic pressure due to a plant cell being placed in a hypotonic solution. • Is pressure on inside of a cell against the cell wall. • Only in plant cells
What is Plasmolysis? • The Shrinking of cell membrane from cell wall in a plant or bacterial cell, caused by loss of water through osmosis. • from Greek lusis, a loosening.
What is Crenation? • Crenation is the contraction of a cell after exposure to a hypertonic solution, due to the loss of water through osmosis. • Crenation occurs because in a hypertonic environment, osmosis. • As a result the cell shrinks and forms abnormal notchings around its edges.
What is cytolysis? • Cytolysis, or osmotic lysis, occurs when a cell bursts due to an osmotic imbalance that has caused excess water to move into the cell. • It occurs in a hypotonic environment. • Where water moves into the cell by osmosis where the volume exceeds the membrane's capacity and the cell bursts. • The presence of a cell wall prevents the membrane from bursting, so cytolysis only occurs in animal and protozoa cells which do not have cell walls.
Active or Passive Transport • • • Active Endocytosis Diffusion Passive Exocytosis Active Osmosis Passive Oxygen Carbon dioxide Passive Sugar Passive Water Passive Pinocytosis Active Phagocytosis Active
Leaf Anatomy
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