Microscopy And Organelles Flashcards
Light microscope
2 lens objective and eyepiece
X1500 magnification max
0.2 micrometers
Laser scanning confocal microscope
Laser beams to scan specimen tagged w fluorescent dye
Focused through pinhole into detector creates 3D image
Look at different depths
Electron microscopes
Use electrons to form image
Higher resolution give more detail
Transmission electron
Scanning electron
Transmission electron microscope
Use EM transmitt through specimen denser parts absorb marking look dark
High resolution
only thin specimen
0.0002 micrometers resol
More than x1000000 mag
Scanning electron microscope
Scan beam across specimen knocks off electrons gathered in cathode ray tube
Forms an image show surface of specimen in 3D
0.002 micrometer resol
X500000 magnification
Magnification
Image size/object size
Sample preparation
Dry mount
Wet mount - squash or smear
Dry mount
Cut into v thin slices sectioning
Centre of slide and placed over sample
Wet mount
Specimens suspend in liquid cover slip placed at angle can stain specimen before placing slip
Squash slide gently press down cover slip
Smear slide - edge of slide at 45 degree angle smear creating even coat cover slip placed on top
Staining
Cytosol of cells is transparent stains incr contrast between components
Air dry sample and heat fix
Crystal violet and methylene blue attracted to negatively charged components
Nigrosin or Congo red repelled by cytosol cells in stained cells stand out from background
Gran staining
Gram positive retain crystal violet appearing blue or purple (susceptible to penicillin strong cell walls)
Gram negative thinner cell walls lose stain appear red after counter stain
Eyepiece graticule and stage micrometer
Line up stage microm and eyepiece graticule
Each div on stage microm is 0.1mm long
Work out number of divisions of eyepiece in 1 stage microm
Divide 0.1 by number of divisions
Times this number by how many counted divisions
Nucleus
DNA to code for proteins
Histones form chromatin which coils and condenses forming chromosomes
Nucleolus
Responsible for producing ribosomes
Mitochondria
Cellular respiration forming atp
Inner membrane folded forming cristae
Interior= matrix
Contain mitochondrial dna producing own enzymes (smaller than dna circular genome )
Vesicles
Membranous sacs
Single membrane
Transport inside cell
Lysosomes
Specialised vesicles containing hydrolytic enzymes breaking down waste
Cytoskeleton
Present in all eukaryotes
Network of fibres necessary for shape and struc of cell
Controls cell movement as well
Consist of micro filaments microtubules and intermediate fibres
Centrioles present in most
Microfilaments
Contractile fibres formed from actin
Responsible for cell movement and during cytokinesis
Microtubules
Globular Tubulin proteins polymerise forming scaffold like structures
Tracks for movement of vesicles
Spindle fibres in cell division made up of microtubules
Intermediate fibres
Give mechanical strength to cells and help maintain integrity
Centrioles
Component of cytoskeleton composed of Microtubules
2 associated centrioles form a centrosome involved in organistaion of spindle fibres
Flagella and cilia
Each cilium contains 2 central Microtubules surrounded by 9 pairs of Microtubules
Parallel microtubules slide over each other
