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19

Unlike erythrocytes that have a very rigid shape and almost cannot change their size (hence the size distribution is indicative and can be used for diagnostic purposes in medicine), lymphocytes can change their size in a wider range, this is why you see the numbers 6-9 and 10-15 μm. And they indeed cluster into several different groups: so-called "large ...


11

Theoretically... 93 million bp/cell x 650 daltons/bp x 10^13 cells/body x 1.66 * 10^-27 kg/dalton = 0.001 kg So I would say it's not too much of a difference :P


8

This 1969 Steensland paper seems to suggest that the membranes of halophiles are stabilized by sodium ions and they rapidly denature at lower-salt conditions (2.2 vs. 4.3 M). The protein composition of the membrane was generally acidic, stabilized by all the Na+. As far as what the role of the halophile membrane is in sheltering the cell from the high ...


6

DAPI (4',6-diamidino-2-phenylindole) preferentially binds AT-rich DNA (although it binds CG-rich DNA, too), which can give chromosomes distinctive banding patterns if they are polytene or in metaphase. In interphase condensed chromosomes, such as the inactive X chromosomes of female mammals (Barr Body), the relatively high concentration of tightly-packed ...


4

I really like this question as it is such a fundamental underpinning of all life on the planet, yet there is such sparsity of actual information on its origins and why evolution encouraged ATP use over anything else. Here I am talking generally since no specific studies exist in ATP vs other candidates. A lot of the below information is taken from an article ...


1

It is generally known that the smaller (or less complex) an organism is, the more "condensed" it's genome is. For example, bacteria (or some eukaryotes) have operons (http://en.wikipedia.org/wiki/Operon) or overlapping genes using different and they don't have introns, which alltogether saves a lot of space. There are many reasons for that. Available space ...


1

Just to extend the answer from @Amory slightly, I think that the terms active and passive transport are best kept for describing transmembrane movement of molecules. In the case of exocytosis the only transmembrane event is when a secreted protein is first inserted (usually cotranslationally) across the endoplasmic reticulum membrane. I'm not aware of any ...


1

Wikipedia is your friend: Exocytosis... is the durable, energy-consuming process by which a cell directs the contents of secretory vesicles out of the cell membrane and into the extracellular space. and Endocytosis is an energy-using process by which cells absorb molecules (such as proteins) by engulfing them. Emphasis mine. Here's a nifty paper ...



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