Biology paper one

• Eukaryotic cells


  Animal and plant cells
• Prokaryotic cells


  Bacterial cells
• Structures in eukaryotic cells

  • Cell membrane
  • Cytoplasm
  • Nucleus containing DNA
• Structures in prokaryotic cells

  • Cell wall
  • Cell membrane
  • Cytoplasm
  • Single circular strand of DNA and plasmids
• Organelles


  Structures in a cell that have different functions
• Organelles in animal and plant cells

  • Nucleus
  • Cytoplasm
  • Cell membrane
  • Mitochondria
  • Ribosomes
• Organelles only in plant cells

  • Chloroplasts
  • Permanent vacuole
  • Cell wall
• Structures in bacterial cells


  • Cytoplasm
  • Cell membrane
  • Cell wall
  • Chromosomal DNA (circular)
  • Plasmids
  • Flagella
• Differentiation


  A process that involves the cell gaining new sub-cellular structures in order for it to be suited to its role
• Specialised animal cells


  • Sperm cells
  • Egg cells
  • Ciliated epithelial cells
• Specialised plant cells


  • Root hair cells
  • Xylem cells
  • Phloem cells
• Light microscope


  Has two lenses, usually illuminated from underneath, maximum magnification of 2000x, resolving power of 200nm
• Electron microscope


  Uses electrons instead of light, can achieve magnification up to 2,000,000x and resolving power of 10nm (SEM) and 0.2nm (TEM)
• Electron microscopes have allowed the discovery of viruses and detailed examination of proteins
• Magnification


  Magnification of the eyepiece lens x magnification of the objective lens
• Size of an object

  Size of image/magnification = size of object
• Standard form


  Multiplying a number by a power of 10 to get bigger or smaller, with the 'number' between 1 and 10
• Orders of magnitude


  Understanding how much bigger or smaller one object is compared to another
• Prefixes


  • Centi (0.01)
  • Milli (0.001)
  • Micro (0.000,001)
  • Nano (0.000,000,001)
• Using a light microscope

  1. Place slide on stage

  2. Look through eyepiece

  3. Turn focus wheel

  4. Start with lowest magnification
• Preparing a slide


  1. Take thin layer of cells

  2. Add chemical stain

  3. Apply cells to slide

  4. Lower coverslip
• Enzymes


  Biological catalysts that increase the rate of reaction without being used up
• Active site


  The uniquely shaped site on an enzyme where the substrate binds
• Lock and key hypothesis

  The shape of the substrate is complementary to the shape of the active site, forming an enzyme-substrate complex
• Ion

  Measured size / actual size