Cells and Microscopes

• Features of Light Microscopes

  • x 1000 enlarging an image
  • 200 nm possible
  • Both living and dead specimen
  • 2D image
• How do light microscopes work?

  Beams of light shone through to create black/white image staining colour
• Features of Transmission Electron Microscope

  • X 500000 magnification
  • 0.1 nm
  • No colour
  • Only dead specimen (thin sections)
  • 2D
• How do TEM microscopes work?

  Beams of electrons passed through detected on flourescent screen on which image is seen
• Features of Scanning Electron Microscope

  • x 100000 magnification
  • 0.2 nm resolution
  • Dead specimen coated in heavy metals
  • 3D
• How do SEM work?

  Beam of electrons passed over surface of specimen.Dead specimen coated in heavy metals which are toxic and are picked up by fluorescent scent screen.
• Diagram and features of light microscope 


  Features:

  
• Whats the function of the nucleoulus?

  Responsible for producing ribosomes.Composed of proteins and RNA.
• Whats the function of mitochondria?

  Site of final stages of cellular respiration,organic molecules is made available for the cell to use by ATP.Has double membrane-inner membrane is the cristae and the the fluid is the matrix
• Whats the function of vesicles?

  Membrane sacks with storage and transport roles.Single membrane with fluid inside. Transport materials inside cell.
• What is the function of lysosomes?

  Specialized form of vesicles.Responsible for breaking down waste materials in cells, including old organells.
• Whats the function of centrioles?

  Theyre the component of cytoskeleton. Composed of microtubules.Two centrioles form a centrosome
• Whats the Smooth Endoplasmic Reticulum function?

  Responsible for lipid and carbohydrate synthesis.
• Whats the function of the RER?

  Has ribosomes bound to the surface and is repsonsible for protein synthesis and transport.
• Whats the function of the cytoskeleton?

  Organlles held in place by the cytoskeleton.Structural support
• What are some parts of cytoskeleton and what are their functions?

  Microfilaments (actin) - cell shape and movement Intermediate filaments (keratin) - structural support Microtubules (tubulin) - cell division and intracellular transport
• What are the function of ribsomes?

  Attatched to the ER forming the RER.Not surrounded by a membrane and site of protein synthesis.
• Whats the function of the Golgi Apparatus?

  Compact structure formed of cristernae and doesnt contain ribosomes.Modifying proteins and packing them into vesciles.
• What is the first stage of protein production?

  Proteins are synthesised on ribosomes
• Where are ribosomes located during protein synthesis?

  On the rough endoplasmic reticulum (RER)
• What happens to proteins after they are synthesized on the ribosomes?

  They pass into the cisternae of the RER
• What are proteins packaged into after entering the cisternae?

  Transport vesicles
• How do vesicles containing newly synthesized proteins move toward the Golgi apparatus?

  Via the transport function of the cytoskeleton
• What is the next step after vesicles fuse with the Golgi apparatus?

  Proteins enter the Golgi apparatus
• What happens to proteins inside the Golgi apparatus?

  They are structurally modified
• What do secretory vesicles carry?

  Proteins to be released from the cell
• How do secretory vesicles release their contents?

  By exocytosis
• What happens to some vesicles formed during protein production?

  They form lysosomes
• What are the stages of protein production?

  1. Synthesis on ribosomes bound to RER
  2. Passage into cisternae and packaging into transport vesicles
  3. Movement toward Golgi apparatus via cytoskeleton
  4. Fusion with cis face of Golgi and entry of proteins
  5. Structural modification of proteins in Golgi
  6. Release of proteins via secretory vesicles by exocytosis
  7. Formation of lysosomes from some vesicles
• What organelles are only in animal cells?

  • Centrioles
  • Centrosome
  • Cillia/ flagella
• What organelles are only in plant cells?

  • Chloroplasts
  • Large permanent vacuole
  • Cell wall
  • Cell sap
  • Plasmodesma
• Whats the definition of magnification?

  Enlargement of an image
• Whats the definition of resolution?

  The abikity to distinguish between 2 objects close together.
• What do prokaryotic cells have?

  • Cell wall
  • Cell surface membrane
  • Cytoplasm
  • Ribsome (70s)
  • Free chromosomal DNA
  • Flagellum

  Theyre usually 0.1-10 micrometers