Cell size and scale

http://learn.genetics.utah.edu/content/begin/cells/scale/

by araneae • 17 years ago

59 17 17 years ago

learn.genetics.utah.edu

mrshoe• 17 years ago

That zoom effect is great. It reminds me of the ZUI (zooming user interface) described in Jef Raskin's book, The Humane Interface. Oh how I wish someone would build a desktop OS with a ZUI.

cloudkj• 17 years ago

Also reminds me of Seadragon from Microsoft Research.

ugh3• 17 years ago

I didn’t know that chromosomes are so big. The photoreceptor (or sperm, for that matter) seems way too small to fit 46 (23). What am I missing?

araneae5• 17 years ago

DNA only exists in the form of chromosomes at particular parts of a cell's life (namely, cell division) and is a highly organized structure consisting of DNA and of proteins.

Neither sperm nor photoreceptors undergo cell division, so for all its existence its DNA exists in an undifferentiated mass inside the cell. DNA is long, but skinny, so it compacts quite nicely.

ugh3• 17 years ago

Cool. But that also means that photoreceptor cells and sperm divide from cells quite unlike themselves, right? Or does that work differently?

lsb• 17 years ago

It's like a choose-your-own-adventure version of the Eames Brothers' "Powers of Ten" movie!

camccann• 17 years ago

A carbon atom is bigger than a water molecule? Interesting.

Speaking of the carbon atom, there is no way that what seems to be its nucleus is even remotely to scale.

amoeba4• 17 years ago

Best I can tell, they have it wrong. They might be interpreting size differently than I expect but Carbon should be around 220pm and Water around 310pm.

Rough estimates for diameter are based on molecular mass and density; density being variable. I'm curious how they did their calculations.

araneae5• 17 years ago

I'm not sure if it's actually wrong, but rather a function of how they draw atoms versus molecules.

Diameter is a funny concept for atoms and molecules because electrons orbit at different distances around the nucleus probabilistically. The depiction of this carbon atom I think represents this, with the lighter color areas denoting areas of lower probability.

However, drawing such a diagram for a molecule isn't very pretty, because the orbitals for each atom in the molecule overlap. They probably drew the water molecule using intermolecular distances, and then filled in the distances so that each atom was a sphere. In actuality the electrons are found with some probability outside this area.

Cell size and scale

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