scale in biology and cells Flashcards
What is the resolution limit of the unaided eye?
The unaided eye can distinguish things down to about two tenths of a millimetre (= 200 mm)
What is the resolution limit of a light microscope?
The light microscope distinguishes points down to less than 1 micrometre (= 1 um)
What type of microscope is necessary for higher resolution?
An electron microscope (EM) is necessary for higher resolution.
What is the resolution limit of an electron microscope?
An electron microscope can resolve points down to 0.2 nanometres (= 0.2 nm)
why do we use logs
finds the cause for an effect and puts numbers on a human friendly scale
isometry
scaled up and down to carry out the same function
allometry
change/variation needed to carry out same function
body mass or weight is…
a function of the cube of linear dimensions (volume)
bone strength is…
a function of the square of linear dimensions (cross section)
what does surface area is proportional to volume ^2/3 mean
if surface area goes up by 1 the volume can’t match that and vise versa
metabolic rate isn’t proportional to…
mass ^0.75 which makes it allometric
prokaryotic cells
cells with no nuclear membrane
eukaryotic cells
cells where the nucleus is surrounded by nuclear membrane
why are animal cells and plant cells similar sizes
surface area/volume
by dictating the amount of oxygen, nutrients and secretions that can be exchanged in a given time
What are microtubules?
Hollow tubes made of tubulin polymers.
