2.1.1

• types of microscopes

  light

  transmission electron

  scanning electron
• resolution


  the minimum distance between two objects in which they can still be viewed as separate
• magnification


  how many times larger the image is compared to the object itself
• types of slide preparation


  dry mount

  wet mount

  squash slide

  smear slide
• dry mount slide


  when a thin slice or whole specimen is viewed with just a coverslip
• wet mount slide


  when the specimen has water added before lowering the coverslip
• squash slide


  a wet mount slide where you push down on the coverslip creating a thin layer of the sample
• smear slide


  using the edge of another slide smear the sample across the slide creating a smooth even coated specimen that is covered with a coverslip
• eye piece graticule calibration


  align the micrometer and EPG

  count the number of EPG divisions within 1 micrometer division

  1 micrometer division / number of EPG divisions = length of 1 EPG division
• magnification = 


  size of image / size of real object
• when is the EPG calibrated


  Every magnification used
• differential staining


  staining different parts of the cell different colours
• methylene blue


  stains negatively charged material as it is positively charged
• Congo red


  stains background as it is negatively charged so repels positively charged cell liquid ( cytosol )
• crystal violet


  stains gram positive
• safranin


  stains gram negative
• rules of scientific drawing


  use a pencil

  title

  magnification

  annotate and label using ruler

  NO sketching , colouring , shading , overlapping lines
• what do electron microscopes require


  electromagnet

  vacuum

  non-living specimen
• transmission electron microscope


  thin , stained specimen

  beam of electrons passed through the specimen

  the more electrons absorbed the darker the image

  creates a 2D image of internal structures
• scanning electron microscope

  any thickness of specimen

  beam of electrons passed onto the surface of the speciemen

  electron scattering depends on the contours

  creates a 3D image
• light microscopes

  thin layer or alive specimen

  use light

  create 2D coloured images
• pros and cons of light microscope

  easy to use

  portable

  cheap

  alive specimens
• the nucleus contains...


  nuclear envelope

  nuclear pores

  nucleoplasm

  chromosomes

  nucleolus
• nucleus function


  site of DNA replication and transcription

  stores genetic information

  site of ribosome synthesis
• nuclear envelope

  double membrane surrounding all contents of the nucleus
• nuclear pore

  protein channels allowing molecules to enter and leave the nucleus
• nucleoplasm


  cytoplasm for nucleus
• chromosomes


  protein bound , linear DNA and proteins wrapped around each other. Only condense during mitosis or meiosis
• nucleolus


  small sphere

  site of rNA and ribosomal production
• nucleus

  A) nucleolus

  B) nuclear pore

  C) nuclear envelope

  D) chromatin

  E) nucleoplasm

  
• flagella


  whip like tail for mobility and sensory information collection
• cilia


  hair like projections

  mobile - move substances

  stationary - sensory collecting
• centriole

  made of microtubules and form centrosomes in pairs

  involved in spindle fibres production and organisation of chromosomes
• cytoskeleton structure


  a network of protein fibres consisting of microfilaments , microtubules and intermediate fibres
• cytoskeleton function


  provide mechanical strength , maintenance of shape and stability

  microfilaments - whole cell movement

  microtubules - internal movement
• endoplasmic reticulum


  a folded membrane containing cisternae
• rough ER function

  protein synthesis as covered in ribosomes
• smooth ER function


  lipid and carbohydrate synthesis and storage
• Golgi apparatus


  folded membrane containing cisternae

  forms vesicles , glycoproteins , enzymes , carbohydrates , lysosomes

  modifies and stores lipids

  sends molecules to destination
• lysosome

  vesicle of hydrolytic enzymes involved in phagocytosis , exocytosis , autolysis , digests worn out organelles