Organelles

• Cytoplasm function


  All cellular contents between the plasma membrane and the nucleus. Has two components: cytosol and organelles
• Cytosol (Cytoplasm) function


  Liquid matter found in cells where the organelles float in it.
• what percentage of water do cells have?

  75-90% water
• Nucleus


  functionA part of the cell containing DNA and RNA and responsible for growth and reproduction
• nucleus membrane


  -double membrane

  -nuclear membrane/envelope
• Nucleus: Chromatin function


  package long DNA molecules into more compact, denser structures.
• Chromatin: Euchromatin


  Light, uncondensed, transcriptionally active (expressed)
• Chromatin: Heterochromatin


  Dark, dense, transcriptionally inactive (silent)
• Nucleolus function


  Site of rRNA synthesis & initial ribosome assembly
• Rough


  Endoplasmic Reticulum functionStudded with ribosomes, involved in protein synthesis
• Smooth Endoplasmic Reticulum function

  An endomembrane system where lipids are synthesized, calcium levels are regulated, and toxic substances are broken down.
• Ribosomes function


  site of protein synthesis (makes proteins)
• Mitochondria function


  cellular respiration, ATP production
• Mitochondria structure


  Consists of an outer membrane that is smooth and an inner membrane that is highly convoluted, forming folds known as cristae.
• Golgi apparatus function


  Modifies, sorts, and packages proteins and lipids for storage or transport out of the cell.
• Golgi apparatus surfaces


  Entry - facing the RER

  Exit - facing the plasma membrane
• Lysosomes function


  Contains digestive enzymes, breaks down excess or worn-out cell parts.
• vesicles function


  transport substances within or between cells, store material
• Microvilli


  short extensions that increase the cell's surface area
• What is this projection?

  microvilli

  
• plasma membrane (cell membrane)


  Regulates what enters and leaves the cell and separates the internal environment of the cell from the external environment
• plasma membrane structure


  phospholipid bilayer, which forms a stable barrier between two aqueous compartments.
• where is microvilli located in the body?

  found primarily on the surface of epithelial cells lining the intestine and kidney.
• Cilia


  The hairlike projections on the outside of cells that move in a wavelike manner
• Where is cilia found in the body?


  on the cells lining the respiratory tract where they help to clear mucus and debris, and on cells lining the fallopian tubes where they facilitate the movement of the egg.
• What is this projection?

  cilia

  
• Flagella


  A long, whip-like filament that helps in cell motility
• Where is flagella found?


  sperm
• How is the plasma membrane selectively permeable?


  Only certain substances can cross (small, noncharged molecules). Only specific molecules like water and gaseous molecules can pass through the cell membrane directly
• What is simple diffusion and how does it occur across the plasma membrane?

  the movement of molecules from an area of higher concentration to an area of lower concentration without the use of energy or assistance from transport proteins.
• what substances can travel through simple diffusion

  oxygen (O2), carbon dioxide (CO2), nitrogen (N2) and steroids
• types of facilitated diffusion

  channel mediated and carrier mediated
• how does water travel through the plasma membrane?

  aquaporins, but small amounts can also diffuse straight through the plasma membrane
• Mitosis


  Produces two identical daughter cells
• Meiosis


  Produces four genetically uniquedaughter cells
• Apoptosis


  programmed cell death
• necrosis


  death of tissue
• What is active transport across the plasma membrane?

  movement of molecules against their concentration gradient, from an area of lower concentration to an area of higher concentration. This process requires energy in the form of ATP and involves transport proteins such as pumps.
• What is osmosis and how does it occur in cells?

  Osmosis is the diffusion of water through a selectively permeable membrane from a region of lower solute concentration to a region of higher solute concentration
• What is channel-mediated diffusion?

  molecules pass through selective protein channels in the plasma membrane, moving down their concentration gradient without energy.