2-cell anatomy: organelles Flashcards
how can you visualize internal cell structures?
fluorescent-based microscopy techniques
electron microscopy
what structures exist within the cell?
organelles
cytoskeleton (filaments/proteins)
what is light microscopy and what is the resolutioin
relies on glass lenses and light
resolution of 0.2 um
what is electron microscopy and what is the resolution?
relies on electron beams and electromagnets as the lenses
resolution of 0.1 nm
why is light microscopy favored to view cell structures?
-sample preparation is straightforward
-sample preparation is inexpensive
-overall, it is relatively non-destructive to cells
-can be used to visualize living cells of fixed (dead)
what can we use to stain and visualize contents within a cell?
fluorescent probes
what is the basic concept of fluorescent dyes?
-small fluorescent molecules that selectively bind to various cellular components can be added to cells
-dyes concentrate in different parts of the cell and can be used to highlight specific parts
-visualized using fluorescent microscope
what is an example of a fluorescent marker protein ?
GFP : green fluorescent protein
how does GFP work?
-gene sequence encoding GFP can be ligated to a gene sequence that encodes a protein of interest
cells _______ the GFP tagged fusion protein
translate
what is an advantage of GFP
GFP fusions can be visualized in live cells
examples of fluorescent proteins used in light microscopy?
GFP
Immunofluorescence
what is the basic concept of immunofluorescence?
-proteins visualized using antibodies and fluorescence
-antigen+primary antibody + secondary antibodies +marker
what is the main difference of GFP and immunofluorescence?
GFP tags can be used in live cells
Immuno- added to cells after they are dead
which antibody is fused to a fluorescent marker in immuno?
secondary
Hoechst dye marks what
nuclei
what is another use for fluorescent probes?
Genetic engineered animals
General Electron microscopy?
-EM has higher resolving power
-EM sample preparation is more complex
-EM is more destructive to cells
-EM can only be used on dead and dried specimens
Transmission Electron Microscopy general?
-samples stained with electron dense materials
-image collected based on electrons that move through sample
-samples are thinly sliced
-2D
Scanning EM
-simpler, small, cheaper than TEM
-lower resolution than TEM
-samples coated with electron dense heavy metals
-image collected based on electron scattering off sample surface
-image is 3D
what are organelles
specialized subunit within a cell that has a specific function, and usually separately enclosed within its own lipid bilayer
most organelles are bound by _________
lipid bilayers
what are some benefits of organelles
-allows for separation and specialization of cellular processes
-allows for efficient consolidation of functions within specific compartments
-allows for isolation of potentially deleterious reactive molecules/waste products