[Nescafe]

Hi,

Can someone explain to a chemistry guy what does it mean to fix cells? Are they dead or alive?

Nescafe.

[Arkcon]

Most definitely dead.  Its hard to just Google for 'fix' and get a useful answer, what you want is fixation (histological) -- http://en.wikipedia.org/wiki/Fixation_%28histology%29#Types_of_Chemical_Fixatives

[Nescafe]

Most definitely dead.  Its hard to just Google for 'fix' and get a useful answer, what you want is fixation (histological) -- http://en.wikipedia.org/wiki/Fixation_%28histology%29#Types_of_Chemical_Fixatives

So we kill them to get a visual on what state they were in at a particular time. For example if we wanted to get an idea of their living status upon introduction of agent x after a y amount of hours?

Thanks,

Nescafe.

[Arkcon]

Advances are made all the time, however, there isn't much visible in a living cell without differential staining.  The things you see in diagrams in the textbook are compilations of various stained, fixed cells.  However, fluorescent labels on molecules, as just one example, can allow for selective visualization of cellular processes.

[Nescafe]

Advances are made all the time, however, there isn't much visible in a living cell without differential staining.  The things you see in diagrams in the textbook are compilations of various stained, fixed cells.  However, fluorescent labels on molecules, as just one example, can allow for selective visualization of cellular processes.

That helps, thanks.

Nescafe.

[JGK]

When I was at University we had one professor who believed that any cellular structure observed in fixed and stained cells under a microscope was not real, just an artefact produced by the fixation/staining process. 

[Nescafe]

When I was at University we had one professor who believed that any cellular structure observed in fixed and stained cells under a microscope was not real, just an artefact produced by the fixation/staining process. 

That's just great. And my professor always said that our planet is just a small particle linked strongly to a giant's head, when it rains its just the giant taking a shower and when it snows that's just the giant's dandruff. Brilliant argument.

Nescafe.

[Arkcon]

Well, the points made by teachers when they get philosophical like that (I mean, unless they are Philosophy professors) they're trying to get you to realize that what you're seeing is an abstraction of what is really there.  For example, often in textbooks there are the electron micrographs that show the cell membrane as a double dark line.  And everyone goes, 'A-ha, lipid bilayer.'  But really, the polar heads have attracted more of the heavy metal contrast agent, and the lipid parts attract less.  The dark line is osmium clumps, not the actual membrane components.