Cookie

I agree wholeheartedly about the media's mishandling of science. One of the reasons I am interested myself in getting into science journalism - there are far too few journalists with a thorough scientific background (in Canada at least - I don't know how it is for other places). My biggest pet peeve with non-science reporters is that they almost never report about science as a PROCESS. They treat it like a series of "groundbreaking discoveries" - half of which seem to conflict with what they reported about the same thing last week (i.e. Eating food X will kill you...no wait, maybe it don't.). What the public gets from this is "scientists are chasing their tails" when really it's just the scientific method at work. I can understand the challenges to journalists trying to cover science - some scientists are so hostile toward all journalists just as a general rule that even the good ones have a hard time sometimes. And some editors dont' understand the science, even if the journalists do - and quite often something can wind up in print different from the way it was written because the editor has misinterpreted. And part of the problem is also that science coverage costs the most to produce, on a line for line basis - so unless you're a major paper, you don't cover 99% of the science that's going on. Hard to stay balanced when you're only scratching the surface like that. A great book on science in the media is Dorothy Nelkin's "Selling Science," if anyone is interested. Cookie

There are many things that contribute to the development of cancer. One way that both ionizing radiation and certain chemical carcinogens cause problems is by damaging the DNA - they both can cause the formation of free radicals which damage DNA and proteins (and other molecules/tissues). Over time, if this damage isn't repaired, then it can screw up all the cell cycle control mechanisms and lead to the development of cancer. Cookie

I took an AP Chem test in high school - scored a 3. It was a good experience but I'm still glad I took all my intro courses. The test was challenging, but I found the hardest thing was not having a lab component to the AP course at my high school - definitely a disadvantage on the exam, I found. Cookie

We don't manufacture eggs throughout our lifetimes. All the eggs a woman will ever have are present at birth. Just a thought though...since eggs are continually lost over a woman's lifetime, maybe it's nature's way of making sure that we're not having babies when we're too old to carry them to term? I don't know...just throwing out ideas - your question is a good one. Cookie

I'm not sure - perhaps someone else knows more, but I think the individual molecules remain intact (i.e. you still have water at the end, not oxygen and hydrogen). Probably what happens is that the force of the rock hitting the ice breaks up the hydrogen bonding in the ice crystal lattice, causing the crystal to shatter. Cookie

Anything by Phil Collins. Second - Anything by Genesis. Cookie

Well, I'm biased, but where I am, biochemistry is the most "well rounded" of all of the science degrees offered. It has the most required courses, and is arguably the most multidisciplinary. Certainly they are (At least here) one of the most employable degrees, since it gives you a background in so many different things. You get a taste of practically everything - so you can really do a lot of different things with a biochem degree. Depends what you really want to do when you're done. Cookie

Girls are not really "fertile" until puberty either. Fertility requires ovulation, and while girls have all the eggs they'll ever have before they're born, they don't begin ovulating until puberty. And really, to say that girls have "eggs" before they're born is a bit of a misnomer - they actually have follicles, which will, under hormonal stimulation, develop into eggs. Cookie

I think you need to use the Henderson Hasselbach equation. Been awhile since I've done acid-base chemistry though. Cookie

You need to supersaturate the solution. Since you probably don't have a lot of the compound, you'll want to just add a small amount of water (just enough so that it will go into solution, not any more!!), then let the solution evaporate slowly over time. Cookie

With regard to filter paper disks - you can use ordinary filter paper (which you should be able to buy at any science supply place - wherever you got the agar plates should have filter paper). Just use a hole punch to make the disks. Coffee filters might work but they're a bit too thin. Ideally you want something that's pretty absorbant and will hold the liquid in one place so it diffuses out at a controlled rate. Maybe some heavy duty paper towel disks? About Glider's question - yes, you'd expect that the bacteria would begin to grow back in toward the disk after the inhibitory effect has worn off. I think the main antibacterial additive to mouth wash is the alcohol, and bacteria will readily metabolize it, so it will gradually decrease below its inhibitory concentration over time. You could use an established culture and kill two birds with one stone - first, you'd see the bacteriocidal effect near the disk, then later you'd see the culture start growing back in from the edge of the inhibition zone. Alternatively, you could apply the mouth wash to the plate directly (better done if you're pouring your own plates or can do an agar overlay) and then plate the cultures on top and see if it stops them from establishing themselves. That one's a little harder to be quantitative with though. Cookie

One thing you could do, which actually is more like what is the usual accepted protocol for antimicrobial testing, is this: Establish the cultures - make sure there's an even lawn of growth over the plate (usually it's better to do an agar overlay, if you are able, but if all you have are prepared solid agar plates, then just make sure you plate your swabs evenly). Soak small (~8mm diameter) filter paper disks with each of the mouth washes. Let them dry. Place each of the disks on the culture plate, leaving enough room between disks so that the zones of inhibition do not overlap (i.e. no more than 4-6 disks/plate, evenly spaced). Add one small drop of water to the top of each disk (this will help the mouthwash diffuse from the disk and into the agar, where it can act on your bacteria). Incubate the plates for a period of time, and then measure the zones of clearing around each of the disks. For more info about this, check out the Kirby Bauer antimicrobial screening technique. It's the method of choice in antimicrobial testing labs. Also, be sure to include enough replicates (i.e. do everything in duplicate at least) as that will make your results more convincing to the judges. As for Gram staining - feel free; if you are able to take pictures of the slides, it's a great visual for a science fair presentation. However, it is probably not the best way to be quantitative in an experiment like this, because counting under the microscope using a normal microscope slide isn't very accurate. You need something called a hemocytometer, and they can be pretty expensive if you're only going to use it once. With the Kirby Bauer method, the zones of inhibition around the disk provide a direct quantitative measure of antimicrobial activity. If you divide the zone of inhibition of each mouth wash by the zone of inhibition produced by a disk soaked just in water (your control), then you can calculate a relative index of antimicrobial activities, which allows you to easily rank the results. Anyway - just a thought. I do a lot of this sort of thing, so if you have any more questions, please fire away. Cookie

I don't know how, but I'd guess you could make buckminsterfullerene - I mean, they make carbon nanotubes, which are essentially the same carbon polymer idea just a different shape. Cookie

saddle

Well, it's like short and tall people. There's no great fitness advantage to being tall, and tallness runs in certain families, but that doesn't mean short people have been bred out of the population. The advantage of having a long neck is only conferred once ther's a significant advantage to being able to eat taller leaves - this was probably a very graduaol response - talking time scales of tens of hundreds of generations. Cookie

Well, early on, giraffes with slightly longer necks probably had no real advantage over giraffes with regular necks. But they had no disadvantage either, so the gene survived, continued to evolve, and eventually giraffes evolved that had a significantly longer neck -- at which point they had the advantage of being able to eat higher leaves. Giraffes with short necks then become disadvantaged, and are eventually bred out of the gene pool, leaving on long-necked giraffes. Cookie

Plus, you want to leave room (volume wise, I mean) to adjust the pH with HCl. Then you fill to the mark with water. Cookie

Go see a doctor - if you haven't changed your diet or your exercise and you're not under unusual stress levels, then it might be a sign of a thyroid problem, or something like polycystic ovarian syndrome, which seems to be awfully common these days. Cookie

The whole idea is that grapes can handle temps down to about 31 degrees. Water will freeze at 32 degrees, so as long as there is a wet ice/air interface, the temp of the leaf will be held at 32 degrees. The grapes have to be continuously sprayed - obviously if the water freezes solid and there's no wet surface, then the temp can drop much lower than 32. Cookie

Well, if you just want to plant seeds and move them to soil once they've sprouted, then the key thing is moisture and most plain agar plates should work fine so long as they are moist. (but then again, so will a moist paper towel) If, however, you want to regenerate whole plants from plant parts, or you want to do long-term plant tissue culture then you're going to need several other micro and macronutrients, and my advice to you at that point would be to buy it prepared from a science supplier because that will probably work out cheaper for you than having to buy every individual component. Unlike bacteria, as YT alluded to, plants are rather finicky critters in a cultured environment. Bacteria and fungi will grow pretty much on anything, plants will not. Cookie

I have: Biochem III + Lab Plant Physiology + Lab Library Science And then two independent studies in the research lab: Molecular Mechanisms of Inflammation Antitumor Activity of Natural Products Cookie

Well, they engineer yeast (a fungus) to produce all kinds of proteins & secondary metabolites. No reason to think that they couldn't do the same with mushrooms (also fungi), given the appropriate genetic information and enough info about the biochemical pathway being introduced. Things get a little tricky if you have to introduce multiple genes, and sometimes it's hard to predict what the foreign metabolite will do to the host that's expressing it, but theoretically, it's possible. Cookie

It's caused by protein denaturation on cooking. There's a protein called crustacyanin (or something like that - can't remember off the top of my head) which binds a substrate that on it's own, is orange, but when it is bound to the protein turns blue-black. When the lobster is cooked, the protein denatures, forcing the substrate back into the orange form. Since the protein doesn't renature on cooling, the substrate has to remain orange. Cookie

Not only that - water is fundamental in our understanding of biochemistry & metabolism. Life would be very different if we were not made up of mostly water! Cookie

Also, there are different varieties or cultivars of grapevine (same species, but slightly different characteristics) are possible too. One of the plants that I work with in the lab, for instance, has 12 different varieties all considered to be the same "species" but their chemical compositions are sometimes very different. Cookie