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chadn

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Everything posted by chadn

  1. In plants there are examples of male sterility that due to genes in the mitochondria. This is typically referred to as Cytoplasmic Male Sterility and there are nuclear based genes or alleles that can rescue this. The exact genes and mechanisms involved is poorly understood.
  2. chadn

    sugar

    There are numerous "sugars." Sucrose being typical table sugar and so what most people think of when you say sugar. All your sugars are made up of Carbon, Hydrogen, and Oxygen. Beyond that you have to be a lot more specific as the exact chemical formula and stereochemistry of all the various sugars is huge. I will give you this. D-Glucose is the most common monosaccharide on Earth. Its formula is C6O6H12. Heres the structure and stereochemistry: http://en.wikipedia.org/wiki/Glucose If thats not what your looking for than you have to be a lot more specific as there are too many sugars to go into detail about.
  3. I understand that perfectly. But its hard to give an answer to such a vague question. Personally I think he/she is probably more interested in what goes on at the cellular level. If he/she is indeed interested in what goes on at the molecular level they should be more specific....such as maybe what type of signalling goes on to bring about erections.
  4. Biochemically it consists of much the same stuff as the rest of your body. Perhaps your more interested in physiology and cell types?
  5. B-DNA doesnt need to denature to form A-DNA.
  6. The A-form of DNA exists under conditions of dehydration or high-salt concentrations. The Z-form I believe exists only in the lab. In addition to these three there are also C, D, E, and P forms. All of these....if I am correct are found under laboratory conditions, only. I could be wrong about this, however.
  7. Arabidopsis thaliana is a dicot and has an aleurone layer.
  8. Carbonic anhydrase catalyses the reaction of CO2 with H2O to form H2CO3. The second reaction doesnt require catalysis to my knowledge.
  9. Thanks for propagating the Religion vs Science argument.
  10. I've alwaysed used dry skimmed milk, mixed in PBS for blocking.
  11. Staining is essential to observing microorganisms with a light microscope so really the disadvantages of differential staining are those that arise when compared to simple staining techniques or to other microscope types. I's say one disadvantage lies in the fact that differential staining is more complicated and not as easy as simple staining. Another disadvantage could be the fact that differential stains tend to be specific to certain microorganisms, like gram positive or gram negative bacteria, so you can only stain certain species with a particular stain, whereas simple staining allows you to view more variety.
  12. I dont think anybody has claimed that Ca(OH)2 is as good as CaO, but your posts make it sound as if Ca(OH)2 is completely worthless in neutralizing soil pH, when in fact it is quite effective. And those other factors are essential. If you have a removal of Ca from the solution then more Ca(OH)2 will disassociate, increasing the OH- concentration. If we look at as simply the disassociation of the compound in basic water we do not see this and the effectiveness of the Ca(OH)2 is not fully realized.
  13. But this isnt basic water, this is the soil solution. Soil Chemistry is a whole sub-branch of its own, much like biochemistry. You do not deal with simple, basic solutions of water and one or two chems. A soil chemist I know once told me a story about a conversation he had with a physical chemist. The guy said "we spend all this time coming up with these rules for solutions and you guys go and throw dirt into them..." Soil Chemistry is messy. With soil chem one must deal with something called reserve acidity. H+ ions in soluton do not necessarily come strait from the disassociation of water. Instead they arrive in the soil solution indirectly, with the majority being absorbed to the Cation Exchange surfaces of clay particles. Ca2+ has this little tendency to become absorbed to these surfaces and be taken out of the solution. That is why Ca(OH)2 makes such an excellent liming material, it will not stay wrapped up with the hydroxide ions, but instead find its way to negatively charged clay surfaces.
  14. It is used and its an excellent source of liming material. (In agriculture the term lime can refer to almost anything that is used to reduce pH). CaO has a higher Calcium Carbonate Equivalent and so is a better liming material, but slaked lime is still an excellent source with a CCE of 134. CCE or Calcium Carbonate Equivalent is a method of comparing the effectiveness of liming materials. It uses Calcium Carbonate as the standard and assigns it a value of 100. The higher the CCE the more effective the liming material and anything with a CCE of over 100 is an excellent source. If there is a reason why slaked lime is not as common it has to do with the availability and not to its effectiveness.
  15. Thanks for the info Martin. I am interested in particle physics, however, as I am sure you are aware, the availability of information on theories other than string is limited. Until you last post I was completely unaware of Ambjorn and had only had time to really examine string theory. I will greatly enjoy the resources you have posted. Thanks.
  16. What about Loop Quantum Gravity? Of course as I understand, it has few supporters and is no where as advanced as String Theory. I've been meaning to look into it some more, but just havent had the time.
  17. How the hell do you get v2=2/3 v1 from that? Shouldnt it be v2=(2mv1)/3m?
  18. True, but I just dont want Primarygun to get the wrong impression. Say he was working with some type of Carbon compound, in that case you have absolutely no clue what the substance is with nothing more than mass and percent composition.
  19. Im going to have to toss my vote with everyone else on this issue. Diatomic Hydrogen is Hydrogen in its elemental form. You can call it a molecule, but I am failyr certain that compounds consist of at least two different elements.
  20. Im not sure. H2SO4 is the empiracle formula, but you cant actually say that is the actual chemical formula of your substance. Any formula that fits the mole ratio is a possibility and I cant remember if in such cases you identify the substance by its empiracle formula or not.
  21. hehe, the naming of compounds is truly an evil business. There are a whole set of rules that govern the process. For instance in Organic Chem a summary of the process would look like this: 1) Find the longest carbon chain which contains the functional group or multiple bond if present and name it (using the correct ending). 2) Number the longest chain (left to right or right to left) so that the functional group/multiple bond/longest side chain (branch) is on the lowest numbered carbon possible. 3) Name each side group but change the ending to -yl. 4) Use a prefix di-, tri-, tetra-, etc. to denote how many side groups of each length are present. 5) Before naming the side group give the number of the carbon to which the side group is attached. 6) Arrange the side groups in alphabetical order ignoring the prefixes di-,tri-, etc. The molecule you listed would end with aldehyde because it has a double bonded oxygen and at least one single bonded hydrogen on the carbon. I cant remember why you have the prefix form.
  22. I think the hard-part of redox reactions is not the concept of gaining and losing electrons, its balancing them. I absolutely despise balancing half reactions, because of all the rules that go along with adding H+ ions and everything.
  23. Thats why I only drink enough water to wet my throat when working out.
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