Introduction to cells

• Cell theory

  1. All organisms are composed of cells, smallest unit of life is a cell, all cells come from pre-existing ones
• Differentiation 


  the alteration of a cells shape and function through gene expression
• Emergent Property


  A property of a system that does not appear in any of its component parts; e.g. brain(which think) is composed of many neurones (which don’t)
• Growth 


  an increase in physical size
• Homeostasis 


  process by which organisms maintain a relatively stable internal environment
• Magnification


  the ratio of image size to actual size
• Metabolism


  all of the chemical reactions that occur within an organism or within a cell
• Micrometre (um)


  1/1000 of a mm
• millimetre (mm)


  1/1000 of a metre
• nanometre


  1/1000 of a um
• objective lens 


  the part of the microscope that is nearest the object/specimen
• Paramecium


  a single-celled organism. it moves using cilia and feeds using an oral groove
• reductionism

  biological reductionism is the idea that you can explain complex processes by looking at the simple component parts
• scale bar


  a line on a microscope image which is labelled with the actual size of the line. From this the magnification can be calculated
• Stargardt’s disease


  a degenerative eye disease that has been the target of stem cell research
• Stem cells


  cells that divide and remain undifferentiated. two types are totipotent and pluripotent
• surface area to volume ratio

  a ratio that decreases as cells grow larger. Above a certain size cells do not have a large enough surface to exchange gases or nutrients to support the volume of the cell.
• system


  a level of organisation that includes organs, tissues and cells
• Tissue


  a group of similar cells with a common function and structure
• characteristics of living 


  response to growth, reproduction, excretion, nutrition, respiration, homeostasis