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Prokaryotic vs Eukaryotic Cells

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					Prokaryotic vs Eukaryotic Cells
Cellular Hierarchy
• Some organisms are unicellular (single celled);
  the cell carries out all life functions. Unicellular
  organisms are prokaryotic.
• Multicellular organisms have many cells that
  work together to carry out life processes.
• Tissues are groups of cells that perform the
  same function. Organs are several types of
  tissue working together to perform specific
  functions.
Cell>Tissue>Organ>Organ System
• An organ system is a group of organs
  working together for a particular function.
  For example, your digestive system
  breaks down food and puts it in the blood.
  Your circulatory system moves blood
  throughout your body. Your respiratory
  system puts O2 into your blood to be used
  by cells for respiration, and removes H20
  and CO2.
Organelles in unicellular organisms…

                   • Work like the organ
                     systems of
                     multicellular
                     organisms.
                   • Each organelle has a
                     specific function that
                     helps keep the one-
                     celled organism alive.
Cell Membranes
• Are found in ALL cells.
• Help cell to maintain homeostasis
  (keeping a balance of solutes within a
  cell).
• Are selectively permeable, meaning that
  only certain substances can go through in
  either direction.
• Made of phospholipid bilayer.
Passive Transport
• Does NOT require energy.
• Molecules move through the cell
  membrane from areas of higher
  concentration to areas of lower
  concentration.
• There are 3 types of passive transport –
  diffusion, facilitated diffusion, and osmosis.
Diffusion & Facilitated Diffusion
• Diffusion is the process by which
  substances move directly through the cell
  membrane.
• Facilitated diffusion involves the help of
  a carrier protein to move a substance from
  one side of the cell wall to the other.
Osmosis
• The movement of water from an area of
  high water concentration to an area of low
  water concentration through a semi-
  permeable membrane.
• Hypotonic has a lower concentration of
  solute (higher of water).
• Hypertonic has a higher concentration of
  solute (lower of water).
• Isotonic means the solute concentration
  is the same inside and outside the cell.
Osmosis ALWAYS occurs from
hypotonic to hypertonic…
Active Transport
• A process of moving material across the
  cell membrane from an area of low
  concentration to an area of high
  concentration
• Requires energy to happen.
• Exocytosis removes materials from a cell.
• Endocytosis brings materials into a cell.
  The membrane “absorbs” the material.
Factors Affecting Cellular Activity
• Volume – cells with large internal volume
  cannot efficiently transport materials to the
  organelles that need them.
• Surface Area – the greater the surface
  area, the more efficient the cell.
• Environmental Factors – most cells
  function best within a specific range of
  temperature, light, and pH. (ex – plants)
Fluid Pressure in Cells
• Fluids are liquids and gases. Pressure is
  a force (push or pull) applied uniformly
  over an area.
• Blood Pressure – pressure exerted by
  blood on the walls of blood vessels.
• Turgor Pressure – pressure that plant
  cells put on each other when full of water;
  allows plants to stand up and move water
  up the stem or trunk to the top of the plant.
Review
• Unicellular organisms have one cell; multicellular have
  many.
• Cells make tissues, which make organs, which make
  organ systems.
• Organelles act as organs in a cell.
• Passive transport (diffusion/osmosis) does not require
  energy. Active transport does.
• Volume, surface area, and environmental factors
  (temperature, light, pH) affect cellular activity.
• The amount of fluid pressure in a cell affects its
  efficiency.

				
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posted:8/5/2012
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