The cell, cellular Respiration and photosynthesis

• Cell


  The smallest unit of life with complex organisation
• Components of cells


  • Proteins
  • Carbohydrates
  • Lipids
  • Nucleic acids
  • Water
• Plant and animal cells

  • Consist of cell nucleus, cytoplasm and cell membrane
• Prokaryotic cell


  Cell without a nucleus
• Eukaryotic cell


  Cell with a nucleus
• Cells differ in size, shape and structure to perform specific functions
• Differentiation


  Cells becoming specialised to perform a specific function
• Specialised cells


  • Muscle cells contract and relax
  • Nerve cells conduct impulses
  • Glandular cells secrete substances
• Main components of plant and animal cells

  • Cell wall (plant cells only)
  • Cytoplasm
  • Cell membrane
  • Protoplasm
  • Organelles
  • Nucleus
• Protoplasm


  The living material in plant and animal cells
• Plant cells have a non-living cell wall surrounding the living protoplasm
• Animal cells do not have cell walls</b>
• Cytoplasm


  The material enclosed by the cell membrane
• Organelle


  A membrane-bound structure in the cytoplasm that performs a specific function
• Inorganic components of protoplasm

  • Water
  • Gases (oxygen, carbon dioxide)
  • Mineral salts
• Organic components of protoplasm

  • Proteins
  • Carbohydrates
  • Lipids
  • Nucleic acids
• True solution


  A homogenous solution where particles cannot be seen
• Suspension


  A heterogenous solution where particles can be seen and will sink
• Emulsion


  A solution where the solvent and dissolved substance are both liquids
• Colloidal solution


  Particles too big to float or sink, held in suspension by electrical charges
• Sol state

  A more liquid state of protoplasm
• Gel state


  A more solid state of protoplasm
• The sol and gel states of protoplasm are reversible and depend on temperature, pressure and pH
• DNA


  Stores genetic information
• RNA


  Carries information from DNA to ribosomes for protein synthesis
• Parts of the plant cell wall

  • Primary cell wall
  • Middle lamella
  • Secondary cell wall
• Primary cell wall


  • Thin, stretchy, made of cellulose fibres and pectin
• Middle lamella


  Made of pectin, connects adjacent plant cell walls
• Secondary cell wall


  • Thick, inelastic, made of cellulose fibres and lignin
• Lignin


  An organic substance that joins cellulose fibres in woody tissues
• Functions of the cell wall

  • Protects the living contents
  • Gives rigidity and shape to the plant cell
• Ground substance (hyaloplasm)


  The liquid part of the cytoplasm
• Cyclosis


  The circulation of substances through the movement of the cytoplasm
• Functions of the cytoplasm

  • Site of all chemical processes
  • Stores essential substances
  • Maintains cell shape
• Cell membrane


  The thin, living outer boundary of the cytoplasm
• Floating mosaic model


  The current theory of cell membrane structure, with phospholipids and proteins
• Cell membrane structure


  • Phospholipid bilayer with embedded protein molecules
  • Hydrophilic protein parts allow water-soluble molecules through
  • Hydrophobic phospholipid parts only allow non-water-soluble substances through
• Active transport


  The movement of substances through the cell membrane against the concentration gradient, using energy
• Diffusion


  The spontaneous movement of molecules from high to low concentration until equilibrium
• Concentration gradient


  The difference in concentration between two areas