BSCI330 microscopy Flashcards
what are eight common features of all cells?
- cells are highly complex and organized
- cells have a genetic program
- cells are capable of producing more of themselves
- cells are biochemical factories that constantly acquire and utilize energy
- cells engage in mechanical activities
- cells can respond to stimuli
- cells are capable of self regulation
- evolution occurs at the level of cells
what are model eukaryotes?
representative organisms to study because:
- genome has been sequenced
- site-directed and tissue-specific mutagenesis is possible
- expression of multiple genes can be racked across many cells simultaneously
- the developmental sequence is known
what is light microscopy used for?
to visualize individual cells and large-scale cellular structures, but is limited by resolution
what is electron microscopy used for?
allows much higher resolution than light microscopy, but requires special preservation (no live cells) and staining techniques
what is flow cytometry?
uses fluorescent labels to measure levels of specific biomolecules and ions and to sort cells based on expression levels to study separately
can couple info with cell sorter which separates cells based on fluorescence and scatter properties
what is Cell Theory?
Schleiden and Schwann proposed that all organisms are composed of cells
what is resolution?
the ability to distinguish two objects that are close to each other
what is the smallest organelle that can be seen by light microscopy?
mitochondria
what is magnification?
the ability to make something small look big
what is detection?
the ability to know something is there (if something is less than 0.2 microns (limit of resolution) but it emits light, we can see it)
what is the main property that sets the limit of resolution
wavelength of light + size of lens
bigger the lens, smaller the limit of resolution
what is the importance of staining cells?
dyes will localize to specific compartments, revealing functional and physical properties
most dyes require fixation, which kills and preserves cells
chemical dyes work by absorbing light of a particular wavelength
how do fluorescent molecules work?
they absorb light of one wavelength and emits light of a longer wavelength
- this allows for detection of small numbers of fluorescent molecules, since they are viewed against a dark background
what is fluorescence microscopy limited by?
fluorescence coming from out-of-focus parts of cells
how does confocal microscopy work?
uses a scanning laser and pinhole apertures to limit detection of fluorescence to the focal plane (sharpens image)
