Definitions

• Active transport


  The movement of substances from a more dilute solution to a more concentrated solution (against a concentration gradient) with the use of energy from respiration.
• Adult stem cell


  A type of stem cell that can form many types of cells
• Agar jelly


  A substance placed in petri dishes which is used to culture microorganisms on.
• Cell differentiation 


  The process where a cell becomes specialised to its function
• Cell membrane 


  a partially permeable barrier that surrounds the cell
• Cell wall


  an outer layer made of cellulose that strengthens plant cells.
• Chloroplasts


  An organelle which is the site of photosynthesis
• Chromosomes


  DNA structures that are found in the nucleus which are made up of genes
• Concentration gradient


  The difference in concentration between two areas
• Diffusion 


  The net movement of particles from an area of high concentration to low concentration without the use of energy.
• Embryonic stem cell


  A type of stem cell that can differentiate into most types of human cells.
• Eukaryotic cell


  A type of cell found in plants and animals that contain a nucleus.
• Magnification 


  How much bigger an image appears compared to the original object.
• Meristematic cells


  A type of stem cell that can differentiate into any type of plant cell.
• Mitochondria 


  An organelle which is the site if respiration
• Mitosis 


  A type of cell division which produces 2 genet identical daughter cells from one parent cell.
• Nucleus 


  An organelle found in most eukaryotic cells that contain the genetic material of the cell and controls the activities of the cell.
• Organelle 


  A specialised structure found inside a cell
• Osmosis 


  The diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane
• Plasmid 


  Loops of DNA found in the cytoplasm of prokaryotic cells
• Prokaryotic cell


  A type of cell found in bacteria that does not contain a nucleus.
• Resolution 


  The ability to distinguish 2 different points in a specimen.
• Specialised cells


  Cells that are adapted to perform a specific function.
• Stem cell


  A undifferentiated cell that can divide to produce many specialised cells of the same type
• Surface area


  The amount of contact an object has with its environment
• Surface area to volume ratio (SA : V)

  The size of the object compared with the amount of area where it contacts its environment
• The cell cycle 


  A series of stages preparing the cell for division
• Therapeutic cloning 


  Producing an embryo that has the same genes as a patient
• Vacuole 


  An organelle that stores cell sap