anatomy of the cell (includes microscopy) Flashcards
what are the key principles of cell theory?
- cells are the building blocks of all living things
- they only arise from the division of existing cells
- they contain inherited information that is used to control their activities
- the cell is a functioning unit of life
- cells are capable of independent life
what are the two main types of cells?
prokaryotes
eukaryotes
what are the differences between prokaryotes and eukaryotes?
eukaryotes are larger eukaryotes have a nucleus eukaryotes have membrane bound organelles eukaryotes are mostly aerobic eukaryotes are mostly multicellular
what are the differences between animal and plant cells?
animal cells have: No cell wall Usually rounded, can change shape No chloroplasts Glycogen for storage Small or no vacuole Can have flagella Lysosome
how do you calculate the total magnification of a light microscope?
you multiply the ocular lens and the objective lens together
how do you calculate the size of a magnified image?
size of object= size of image ÷ magnification
how do you calculate resolving power?
resolving power R= 1.22 x λ ÷ 2 x sinϴ
n=refractive index
ϴ=the collecting angle of the lens
λ=the wavelength of light used
what is a microscope?
it is a peice of scientific equipment that produces a magnified image of something to make it visible/ more easily visible
what does a compound microscope do?
it creates a magnified image through a series of glass lenses
“compound” means it has at least 2 lenses
the lens focuses the light onto/ through the object
what is fluorescent microscopy?
it enables structures to be seen clearer
uses fluorescent dyes which emit light when excited by certain wavelengths of light
some dyes have natural affinities for specific structures in the cell
others are bound to antibodies which bind to specific proteins
what is an electron microscope?
they use beams of electrons rather than light, as the wavelength is smaller they have greater resolving power
what are the two types of electron microscopes?
transmission electron microscopes (TEM)
scanning electron microscopes (SEM)
what does a transmission electron microscope study?
the fine detail of internal structures of cells
what does a scanning electron microscope study?
they study the fine detail on the surface of cells
what are the cons to using electron microscopes?
Electron microscopes can only examine dead things that have been stained with heavy metals (toxic)
Expensive to buy and maintain and requires a lot of skill to use
Specimen is placed in a vacuum
Can only examine relatively small areas
