What a waste of a decent education
A colleague and I were trying to work out how to use an ancient but useful piece of equipment we’d recently unearthed in a pile of junk abandoned by the previous inhabitants of the lab – a semi-dry Western blotter. Of course the manual had been lost to the mists of time, but there was a helpful diagram inscribed on the side.
“This says we need to put it against the anode,” my colleague said.
“Is that positive or negative?” I asked. “I can’t remember.”
“Me neither.”
We took a poll of random people – the student using the ImageQuant machine in the corner; a post-doc taking a short-cut through our lab; even the mild-mannered guys who were currently camped out calibrating all of the institute’s pipettors. Not a single one could remember the difference between an anode and a cathode.
” ‘Anode’ sounds sort of negative,” my colleague mused. “You know, like asocial or asymmetric.”
“Why don’t you check Wikipedia?” asked one of the pipette guys.
I just checked Wikipedia. None the wiser.
I just remember that cathode ray tubes emit electrons.
It’s the negative (pays off to be Greek).
It’s the positive, actually. Or at least my proteins indeed ran towards it.
That sounds right. It would be easier if it was simply labelled ‘red’.
I hate electricity. Why oh why is the ‘ode that the current comes out of called ‘negative’?
There were red and black leads but you couldn’t tell which parts of the machine they ultimately fed into, as it all happens inside the casing…
Western blotting as an act of faith.
haha, I started thinking about anabolic and catabolic metabolism 😉 Ah, anything to sort it out I guess?
(on the note with semi-wet Western Blot machines though, those are good. I like them….)
Looks like I confused anions with anodes. Awesome. Pays not to be Greek, after all – at least in terms of electricity.
heh. I heartily disapprove of semi-wet blotting.
Remember anions and cations from chemistry, yes? An anion is negatively charged, and a cation is positively charged.
In an electrochemical cell, anions (-) go towards the anode, which means the anode is positive. Cations (+) go towards the cathode, meaning that the cathode is negative. Clear as mud? Yeah, that’s why they’re named that and it’s kind of stupid. But it’s the way it’s always been done, and you know how easy that is to change.
Well, I was pretty unhappy with how much molecular weight marker remained in the gel after the blotting was finished – even the tiny markers. When I do it with wet blotting everything comes over except markers over about 100K. Still, my colleague is optimistic.
Nik, we thought of the Greek a- thing too, so I was surprised it was the other way round. Maybe “node” is Greek for ‘negative’ so the entire word means ‘not negative’?
🙂
Nah, it’s the “ode” part, which means “way”. So anode = “up”-way, cathode = “down” or “against”-way.
Nik, that means I have to turn my blotting apparatus upside-down!
Chemgrrl – all is clear!! I *knew* “an” was negative somehow – diabolical. Thanks for clearing up this mess!
I learned a Dutch mnemonic for this in high school, and it clearly worked because I still remember:
knap – kathode negatief, anode positief
Ah Eva, we had “PANK” (=no money left) positive anod, negative katod.
So fun to remember things like that. Thanks a lot!
I’ll PANK your KNAP, and raise you a Kings Play Chess on Friday.
Hmmm. You should have done O-level Chemistry back in the 70s.
I can still remember being taught that
…which therefore has to be positively charged
Of course, being a physiologist is useful for remembering which are cations and which are anions…
If Jenny had done that, she’d be a super-genius.
Austin, not much of a mnemonic! I don’t have enough brain cells to handle that one.
“AN-ions to the AN-ode, CAT-ions to the CAT-hode”
– worked OK as a mnemonic for me, Jenny. Of course you would have to also know, or remember separately, that cations were positive ions, and anions were negative ions, was what I meant. But somehow for me it was easier to remember that about ions (which were actual “real” things that did stuff, like Na+ and Cl-) then about the equipment/gadgets.
The trick, I guess, is to use the things you remember easily as “cues” or signposts to recall the things you don’t.
It is peculiar how some things you learn stick, and other don’t. My brain is still littered with bizarre oddments from 30+ years back, like lists of Latin prepositions that take the accusative case. In my case I tend to remember particularly the things that we learnt in the form of helpful rhyming couplets. All very odd.
Of course you would have to also know, or remember separately, that cations were positive ions, and anions were negative ions.
I rest my case, m’lud. Now where did I leave my Zimmer frame?
cathode – “pussy-tive” (cat)
as my chemistry teacher used to say
“Roman Catholics are Positive about Good, Negative about Evil”
Take the first letter of the main words…
RC PG NE
and this translates to
Reduction Cathode Positive Galvanic cell, Negative Electrolytic cell.
It’s a lovely acronym but not sure it would help me remember which end is up! Cure worse than disease?
I work with electronics and have an interest in biology, how come biologists don’t have an interest in electronics? Here for more information on Anodes, Cathodes and good old traditional electronics 🙂
http://www.vintage-radio.com/repair-restore-information/valve_how-valves-work.html
Have fun.
Adam
A=+