TRANSPORT MECHANISMS

• Centrioles


  Structures made out of microtubules Help with cell division only found in animals cells
• Vacuoles (Vesicles)


  Storage for water and other substances Animals they are called vesicles
• Pili

  Extensions on the outside of cell that enable it to stick to other cells
• Integral Proteins


  A membrane protein that can pass through the membrane
• Peripheral Proteins


  A membrane protein that sits on the surface of the membrane
• 1. Transport proteins-Allow substances to move in & out -Carrier proteins -Channel proteins -Membrane proteins2. Receptor proteins-binding sites for hormones or other chemicals which cause changes in the cell3. Recognition or marker proteins-identify cells as a certain type (muscle, organ), mark cells as self so that the immune system recognizes them and does not destroy them.


  The 3 jobs of a membrane protein are:
• Diffusion


  Movement of molecules from an area of higher concentration to an area of lower concentration.
• Osmosis


  Diffusion of water through a selectively permeable membrane
• Facilitated Diffusion


  Another type of passive transport, used for molecules that cannot readily diffuse through cell membranes without the help of proteins.
• Active Transport


  Energy-requiring process that moves material across a cell membrane against a concentration difference (High-->Low).Movement of materials through a cell membrane using cellular energy. Needs cell to use it's own energy.
• Factors that decide whether active or passive transport take place

  Depends on the molecule or object being moved
• Hypotonic solution


  A solution with a lower concentration of solutes and a higher concentration of water than inside the cell.
• Hypertonic solution


  The solution has a higher concentration of solutes and a lower concentration of water than the inside of the cell. (high solute; low water)
• Isotonic solution


  The concentration of solutes in the solution is equal to the concentration of solutes inside the cell. Result: Water moves equally in both directions and the cell remains the same size. (Dynamic equilibrium)
• Concentration Gradient and the importance of one in cell transport


  A difference in the concentration of the same substance in different areas. In transport molecules are moving from areas of high concentration to low concentration OR from low concentration to high concentration. Without a concentration gradient transport could not occur and equilibrium would not be reached.
• Pinocytosis


  Cell drinking
• Phagocytosis


  Cell eating
• Endocytosis


  Taking bulky material into a cell
• Exocytosis


  Forces material out of the cell
• Solution


  Have two parts, solvent and solute. Water is the solvent and salt is the solute in a salt water solution.
• Solvent


  The substance that dissolves a solute. Ex. Water
• Solute


  The substance that is dissolved in a solution. Ex. Salt
• Suspension


  Materials that do not dissolve in a solution.
• Diffusion


  the movement of molecules from an area of higher concentration to an area of lower concentration. It occurs due to the random motion of molecules. This process allows substances to distribute themselves evenly throughout a given space.
• Osmosis


  a special type of diffusion that specifically refers to the movement of water molecules across a selectively permeable membrane. When there is a difference in solute concentration on the two sides of the membrane, water will move from an area of lower solute concentration (hypotonic) to an area of higher solute concentration (hypertonic).
• Osmosis

  This movement aims to equalize the concentration of solutes on both sides of the membrane.
• Diffusion

  It is driven by the natural tendency of molecules to move down their concentration gradient until equilibrium is reached.
• Facilitated diffusion


  a passive transport process that uses specific transport proteins to facilitate the movement of certain molecules across the cell membrane. These proteins act as channels or carriers, allowing substances such as ions or larger polar molecules to pass through the hydrophobic lipid bilayer of the membrane.
• Facilitated Diffusion


  does not require energy expenditure by the cell.
• Active transport


  is the movement of molecules against their concentration gradient, from an area of lower concentration to an area of higher concentration. This process requires the cell to expend energy in the form of ATP (adenosine triphosphate).
• Active Transport


  utilizes specific transport proteins called pumps, which actively move molecules or ions across the membrane. This process is essential for maintaining concentration gradients and is involved in various cellular functions such as nutrient uptake and ion balance.
• Semipermeable


  regulate only certain substances to enter, metabolic intermediates to remain, and waste products to exit
• phospholipid bilayer


  hydrophilic heads and hydrophobic tails
• fluid mosaic


  lipids and proteins can move relative to e/o with diverse protein chol, carb molecules
• receptors


  proteins on the surface; transmit the messages to the cell's interior
• transport proteins


  create tunnels; sekect certain subtances to enter and exit the cell
• cholesterol molecules


  prevent fatty acid tails from sticking to each other
• carbohydrates attached to proteins


  define the cell's unique characteristics and identify the chemical signals
• proteins at the inner surfae


  provide cell shape
• simple diffusion


  movement of a solute from an area of high concentration to an area of low concentration. small uncharged lipid-soluble molecules can easily cross cell membrance