Cells

• Cell


  • The smallest living unit in all organisms
  • All living things are made of cells (one or more)
  • All cells come from other, pre-existing cells
• Prokaryote


  Cells that have no nucleus and no membrane-bound organelles

  Consists of proteins

  Bacteria + archaea only known prokaryotes
• Eukaryote


  Cells that have a nucleus and membrane-bound organelles

  Found in multicellular organisms

  E.g. Animals/Plants
• Getting through the cell membrane

  1. Selectively permeable

  2. Keeps things in the cell stable (homeostasis)
• Cytoplasm


  The jelly-like material that surrounds the internal cell structures

  'Background material' inside a cell

  90% water

  Contains organelles such as mitochondria + ribosomes

  Contains dissolved or suspended molecules e.g. proteins
• Cytoskeleton


  A collection of fibers that provide support and play a role in cell movement
• Ribosomes


  Organelles that make proteins (not membrane-bound)

  Responsible for growth + repair of cells

  Located on rough endoplasmic reticulum

  Some lay free in the cytoplasm
• Nucleus


  Holds the genetic material (DNA) and controls cell activities

  'Control center' of the cell

  Arranged in long, uncoiled strands
• Nucleolus


  Nucleus of a non dividing cell

  Where ribosomes are produced

  Some cells contain more than one nucleolus
• Golgi Apparatus


  Formed from cisternae that are lined up in parallel to form a stack

  Packages and sorts materials, determines where to send them
• Mitochondria


  Powerhouse of the cell

  Responsible for cellular respiration

  Power plants that make ATP energy through cellular respiration
• Chloroplasts


  Organelles in plant cells that make glucose through photosynthesis
• Vacuoles


  Storage organelles (plant cells have one large central vacuole, animal cells have several smaller ones)
• Cell Wall


  Additional layer in plant cells that offers protection and shape maintenance
• Rough endoplasmic reticulum
• Rough endoplasmic reticulum


  Encrusted with ribosomes

  Often a sac like shape

  Associated with the manufacture and transport of protein molecules
• Endoplasm reticulum


  System of flattened membrane bound cavities called cisternae that extend throughout the cytoplasm

  Makes cell proteins

  Acts as a temporary storage area

  Involved in the metabolism of lipids
• Smooth endoplasmic reticulum


  Has no ribosomes

  Often a tubular shape

  Associated with the manufacture and transport of fat molecules
• Golgi


  Packages proteins for delivery to organelles

  Produces lysosomes

  Looks like flattened fluid sac, stacked like pancakes
• Lysosomes


  Special type of golgi vesicles that contain digestive enzymes

  Can be transported to the cell surface membrane

  Travel freely in the cytoplasm

  Release content in and out of the cell

  Break down food molecules with help of enzymes
• Centrioles


  2 black dots under microscope

  Lay at right angle near nucleus

  Made up of protein strands called microtubules

  Connect to chromosomes to form mitotic spindles during cell division
• 3 Cell Theories

  1. All living organisms are made of 1 or more cells
  2. Cells are the most basic unit of structure and function in all living things
  3. All existing cells are produced by pre-existing cells