cell biology - 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
• Chloroplast

  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 spreading out of the particles of any substance in solution, or particles of a gas, resulting in a net movement from an area of higher concentration to an area of lower concentration
• 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 contains 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 of respiration
• Mitosis


  A type of cell division which produces two genetically identical daughter cells from one parent cell
• Nucleus


  An organelle found in most eukaryotic cells that contains 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 two different points in a specimen
• Specialised cells


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


  An 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