ch2

• cell theory


  all living things consist of one or more cells

  all cells are produced by pre-exsiting cells

  cells are the smallest living units
• features shared by all cells

  plasma membrane, cytosol, genetic material/nucleic acid, ribosomes
• general features of prokaryotes

  unicellular, simple cell structure, small, found everywhere (even extreme conditions)
• required for exchange will environment (cells)

  must exchange nutrients and waste via plasma membrane
• how to increase efficiency of exchange

  high surface area to volume ratio
• how to increase SA:V without changing volme

  cell compartmentalisation, flattened, membrane extensions
• cell compartmentalisation definition


  allows organelles to have the right conditions and concentration of enzymes and reactants for a particular function
• organelle definition


  a structure within a cell that performs a unique function
• nucleus


  nuclear envelope, membrane-bound, contains DNA

  contains genetic material
• rough ER


  complex system of tubuoles, membrane-bound, ribosomes mind to membrane

  processes and modifies proteins
• ribosome


  made up of ribosomal RNA and protein, non-membrane-bound

  synthesis of proteins
• golgi apparatus


  membrane-bound (unconnected cisternae), vesicles containing proteins

  processes, packages, + transports proteins
• lysosome


  membrane-bound, vesicles containing digestive enzymes

  digests cellular waste material + foreign matter
• smooth ER


  membrane-bound, network of cisternae, vesicles

  synthesis of lipids, carb metabolism, transport of materials, detoxification of drugs and poisons
• mitochondrion


  membrane-bound, contains its own DNA molecule, highly folded cristae

  obtains energy from organic compounds, production of ATP
• chloroplast


  spherical/ellipsical, membrane-bound, own DNA molecule, thylakoid scas

  produces glucose (photosynthesis)
• centriole


  small structure in the cytoplasm, contains microtubuoles

  involved in cell division, formation of cilia and flagella
• cilium/flagellum


  external structure consisting of microtubuoles

  motility (movement of substances across a cell surface)
• vacuole


  membrane-bound, fluid-filled vesicle

  stores substances, cell structure in plants
• plastid


  small membrane-bound, contains DNA molecule

  synthesis, stores organic molecules
• cell wall


  external structure (rigid), only plants

  cell structure + protection, prevents excessive water uptake
• three main functions of cell organelles

  cellular respiration and energy

  creation and synthesis of proteins

  transportation and secretion of proteins and genetic material
• only in plant cells


  chloroplasts, cell wall
• only in animal cells


  centrioles, lysosomes, smooth ER, plasma membrane
• endosymbiotic theory


  host cell engulfed aerobic bacteria and retained it inside as it provided a source of ATP energy (mitochondria and chloroplasts)
• extracellular fluid definition


  anything outside the cell
• intracellular fluid definition


  fluids and materials inside the cell
• external environment definition


  environment surrounding the cell
• internal environment definition


  in a multicellular organism - everything inside the protective barrier
• components of the plasma membrane

  phospholipids, proteins, cholesterol, glycolipids, glycoproteins
• cholesterol definition


  fatty molecules that give stability to the membrane without affecting its fluidity, and reduces permeability of the membrane to small, water-soluble molecules
• roles of transmembrane proteins


  transport, enzymatic activity, signal transduction, cell-cell recognition, intercellular joining, attachment to the cytskeleton and extracellular matrix
• permeable across plasma membrane

  small uncharged molecules (oxygen, carbon dioxide), lipid-soluble non-polar molecule (alcohol, chloroform), small polar molecule (water)
• non-permeable across plasma membrane

  small ions (amino acids, sugars), large polar water-soluble molecules (sugars, proteins, ions)
• diffusion definition


  movement of a substance across a semipermeable membrane down the concentration gradient
• solute defintion


  a substance that can dissolve in a solvent
• solvent definition


  a fluid that can dissolve substances
• solution definition


  after a solute dissolves in a solvent
• concentration gradient definition


  amount of substances when comparing surrounding solution to the cell
• passive definition


  no ATP required