Biology 1.1

• Nucleus


  Contains chromosomes which carry genetic information and controls the activities of the cell.
• Mitochondria


  Site of aerobic respiration
• Cytoplasm


  Site of most cell reactions.
• Cell wall


  Contains cellulose and is a structural support for plant cells.
• Chloroplast


  Site of photosynthesis.
• Vacuole


  Space filled with a watery sugar solution (sap).
• Cell membrane


  Controls the entry and exit of substances.
• Total magnification equation?


  total magnification = eyepiece lens magnification x objective lens magnification
• Magnification triangle?


  I am
• Electron microscope use?


  Has a grater magnification but can only be used to view dead tissue.
• Light microscope limitation?


  Restriction in maximum magnification.
• Iodine solution use?


  Makes nucleus more obvious, stains any starch present and only used to stain plant cells.
• Methylene blue use?


  Makes nucleus more obvious, stains any acidic parts of the cell blue and used to prepare animal cells and bacteria slides.
• Use of specialised cells?

  Specialised cells are more efficient in performing specific functions than non-specialised cells.
• Specialised cell - organisation levels

  Specialised cells are cells with a specific function.
• Tissues - organisation levels


  Tissues are a group of similar cells with a similar function.
• Organ - organisational levels

  An organ is several tissues performing specific functions.
• Organ system - organisational levels

  An organ system is a number of organs working together to carry out specific functions.
• Diffusion definition?


  Diffusion is a passive process which molecules diffuse from an area of high concentration to an area of low concentration, down a concentration gradient.
• Osmosis definition?


  Osmosis is the diffusion of water molecule from an area of high water concentration to an area of low water concentration, through a selectively permeable membrane.
• Active transport definition?


  Active transport is whereby substances can enter cells against a concentration gradient.
• What are enzymes?


  Enzymes are proteins that speeds up/catalyse the rate of a chemical reaction.
• What are enzymes involved in?

  Enzymes are involved in all metabolic reactions building large molecules from small ones as well as breaking down large molecules into small ones.
• What happens if the temperature is too high?

  If the temperature is higher or lower than the optimum temperature, the enzyme will catalyse the molecule at a much slower rate.
• What happens if the active site denatures?

  If the active site denatures it can no longer bind with its substrate, therefore no reactions can occur.