Bio B1

• define magnification

  the degree to which the size of an image is larger than the real object
• define resolution

  the ability to distinguish between two points that are close to each other
• advantages of light microscopy

  relatively cheap

  can be used in the field

  doesn't require specialist training

  can look at living specimens
• disadvantages of light microscopy

  low resolution

  low magnification

  staining is required for some organelles to present
• electron microscope

  uses electrons, instead of light, to form images
• BOTH ANIMAL AND PLANT CELLS

  nucleus

  contains the genetic material, which codes for certain protein
• BOTH ANIMAL AND PLANT CELLS

  cytoplasm

  • liquid substance in which chemical reactions occur
  • contains enzymes
  • organelles are found in it
• BOTH ANIMAL AND PLANT CELLS

  cell membrane

  controls what enters and exits the cell
• BOTH ANIMAL AND PLANT CELLS

  mitochondria

  where aerobic respiration occurs, giving the cell energy (ATP)
• BOTH ANIMAL AND PLANT CELLS

  ribosome

  where protein synthesis occurs
• ONLY IN PLANT CELLS

  • chloroplast - where photosynthesis takes place, providing food for the plant
  • permanent vacuole - contains cell sap
  • cell wall - provides strength to the cell
• prokaryotic cells have...

  • cytoplasm
  • cell membrane
  • cell wall
  • single strand of DNA
  • plasmids
• DNA is a double-helix shaped polymer

  it is made of monomers called nucleotides

  nucleotides are made up of a sugar, phosphate and base

  the four different bases are:

  • adenine
  • cytosine
  • guanine
  • thymine
• lipids are made up of:

  glycerol and fatty acids
• lipids are broken down by lipase enzymes
• proteins are polymers made up of amino acids
• photosynthesis is the process of making glucose from sunlight in the leaves of the plant. it is an endothermic reaction in which energy is transferred from the environment to the chloroplasts by light
• photosynthesis equation:

  carbon dioxide (CO2) + water (H2O) -> glucose (C6H12O6) + oxygen (O2)
• glucose can be used as food or stored as starch
• • enzymes are biological catalysts
  • this means they speed up chemical reactions without being used up in the process
• enzyme process:

  1. substrate collides with active site of enzyme and becomes attached
  2. enzymes catalyses breakdown of substrate
• the factors affecting enzyme activity are...

  • temperature
  • pH
• optimum temperature

  the temperature at which rate of reaction is highest
• when an enzyme denatures, it loses its shape and function
• magnification = image size ÷ actual size
• aerobic respiration:

  C6H12O6 (glucose) + O2 (oxygen) -> H2O (water) + CO2 (carbon dioxide)
• anaerobic respiration:

  glucose -> lactic acid (without oxygen)

  glucose -> ethanol + carbon dioxide (in plants)