lecture 1, 8/27

size, scale, evolutionary theory

rank from largest to smallest unit, and give their relation to one meter: meter, millimeter, micron, nanometer, picometer

largest to smallest:

meter (m) → millimeter (mm), 10ˆ-3m → micron (um), 10ˆ-6m → nanometer (nm), 10ˆ-9m → picometer (pm), 10ˆ-12m

what is the approximate length of adult c. elegans and diameter of xenopus oocyte

1000um

what is the approximate size of eukaryotic cells

5-50um

what is the approx. size of bacteria and organelles

1-2 um

what is the approx. size of a virus

100nm

what is the approx. size of a microtubule or a ribosome

25nm

what is the approx. size of a nucleosome or a protein complex

10nm

what is the approx. diameter of collagen or DNA

1-2nm

how many bacteria would fit in a 1mm cube?

10ˆ9 (10ˆ3 bacteria(1um) in a mm, 10ˆ3ˆ3 gives volume = approx. # in cube)

what is the smallest that light microscopes can see? what does this allow it to detect? how did technological advance help this?

250nm smallest because that is wavelength of light. allows us to see cells. technological advances in light resolution now allows us to see down to 10nm which can show protein

what do electron microscopes allow us to see?

cell subcomponents

what does x-ray crystallography allow us to see?

structure of macromolecules

order weakest to strongest: x-ray crystallography, light microscope, electron microscope

light scope, electron scope, x-ray crystallography

why can we study cellular mechanisms relevant to humans in simpler organisms like yeast, mice, roundworms

molecular homologies from evolutionary relationships! humans and mushroom and corn are super close in the grand scheme of things. complexity of system informs how simply the organism of study can be. ex: study protein synthesis in e. coli bacteria, neurons in nematodes, and sub-regions of brain in mice

why are some cells with identical DNA distinct? why does this matter?

differential gene expression! this informs which cells are best to study for certain processes

rank for size: carbon atom, large protozoan, red blood cell, ATP, diameter of microtubule, c elegans adult worm, yeast, DNA double helix diameter, ribosomes, viruses, yeast, e. coli, rice grain

big to small: rice grain (2mm), c. elegans worm(1000um/1mm), protozoan(500um), red blood cell(8um), yeast(3um), e. coli(0.6um), viruses(100nm), ribosomes(25nm), diameter of microtubules(25nm), nucleosomes(10nm), diameter of DNA double helix(1nm), an ATP(0.7nm), a carbon atom(340pm)