blazinfury

If after one performs an organic rxn and wants to purify their sample of both soluble and insoluble impurities, is there a correlation to temp where insoluble impurities are removed when the sample is hot and then soluble are removed after the compound has crystallized? Or is it more case by case basis? Also why are some impurities removed when the sample has not crystallized and others removed after the sample has crystallized?

What is a liquid liquid critical point? I know that a liquid has critical point is when no phase boundary exists between the 2 phases, but it seems based on what Wikipedia says a liquid liquid critical point is when the two fluids can be separated. Why is this so and under what conditions is this possible?

Cool. Thanks a lot for the clarification. Is it possible to alter either the electric or magnetic field or does one only alter one of them? Also if one increase either the magnetic or electric field does the other field increase as well of you would need to increase it manually in order for the two to balance out?

I have a question about a velocity selector. If one shoots a positive particle like a H+ cation through the selector, how can one force the particle to go more toward either the positive or negative plate? In general, one wants for the magnetic and electric fields to be equal and opposite and thus the particle can move straight. However one can alter either the magnetic or electric fields to force the particle toward a particular pole, correct? Once can also increase the velocity of the particle. If the velocity is increased, then B would decrease and so the particle's direction would be dictated by the Electric Field, correct?

I have read that if disulfide bonds are broken they cannot be reformed. However other bonds may be reformed. I take it that there is no general answer to my quest but all varies case by case.

I have a question about Thyroid hormone. I read that it acts like a lipid. So does that mean that it is like a steroid in terms of it traversing the plasma membrane and then being transported into the nucleus and acting directly on DNA? in addition, people say that steroids are long lasting and this is due to them acting directly on DNA. Are they long lasting because you cannot degrade them or turn them off inside of the nucleus? Then how do we control their level of expression by just creating inhibitors to degrade extra protein that they produce or via RNAi?

I don't really see what you are saying but let me clarify what I am confused about with an example. Lets say you have alpha and beta glucose which are epimers which are diastereomers on the anomeric carbon (C1). Isn't the spectra going to be the same for both of those molecules?

I know that diastereomers have different physical and chimerical properties. I was reading online that diastereomers can be distinguished from one another based on their spectra. I have a hard time understand this because don't diastereomers differ in a chiral center light polarization-- yet all the functional groups are exactly the same?

I read in a book that if a protein is heated its 3 and/or 4 structure is denatured but upon cooling the protein will not be able to resume that conformation back. Is that true? I agree that if those bonds are broken there is no guarantee that those bonds can be reformed but wouldn't it depends on the type of protein, its size, and how many competing bonds there are in terms of determining if it can resume this structure?

I have a quest about Hfr plasmids. Wikipedia said that you mate an Hfr with an F- plasmid the whole thing transfers over. Is that true. I ask because I would think that the Hfr would be too big to transfer over.

Is RNA present in the cytosol as double stranded structures? I know that tRNA can assume double stranded structure but isn't mRNA single stranded? I just want to make sure because I was reading about northern blots and it was states that formaldehyde agarose gel is used to separate the RNA bands specifically to denature RNA and stop it from assuming a self complementary structural shape. Or is formaldehyde used because some RNA assumes this shape and so to equilibrate the solution formaldehyde is used to ensure all RNA is single stranded. Would you deem this principle similar to how sds is used in sds page for protein?

I was taught that reactivity increases down a group in Gr 1 and Gr 2 elements, but I never understood why. Would anyone be able to please clarify this? Is the same true for non-metals as well such as the elements in Groups 5, 6, and 7? Thanks.

If you had a fetus in the womb still attached to the placenta, is there a higher oxygen level within the left atria compared to the aorta? I think that the oxygen level would be greater in the left atria because as blood travels through the body oxygen is constantly being lost. Since the lungs are not patent as of yet, the blood supply that was originally oxygenated at the placenta will lose its oxygen content unless this blood is reoxygenated by the lungs, but since the lungs don't exist it's less. As a side question, lets say we were asked the above question but with the fetus being born (ie lungs working), then I would think that the oxygen concentration in blood in aorta would be slightly larger.

Thank you very much for that clarification.

I am trying to understand the difference between RNAases and ribozymes. Based on what I have read RNAses appear to be a type of ribozyme whose goal is to control the half life of RNA and to degrade viral RNA. Ribozymes are RNA enzymes that perform both catalytic activity and can act as RNAses. Am I missing anything? Thanks.

I need to calculate the effective nuclear charge of Cu2+. The formula that I am using is #protons- (total# e- - valence e-). Cu config is [Ar]3d104s1 Cu2+ config is [Ar]3d9 So the total # of protons is 29. Total # of e- is 27 because we lost 2 due to the ionization. Now would the total number of valence e- be 17 because we are looking at the whole 3rd energy level? So would the answer be 29- (27-17)= 19? Thanks.

I am trying to understand the applicability of Henry's Law, but am having some difficulty. The law makes sense but I find limited utility in it because the increase in solubility occurs at a constant temp and in a closed container. So in that case, is the only way to increase the VP of a gas by physically disturbing it-- ie like shaking a soda can? I am just trying to understand when it would apply since it seems that it really cannot work in our atmosphere due to it being an open system and with frequent temp fluctuations. Thanks.

I have a quest about concentration cells. I understand that they are constructed almost like galvanic cells, except they are spontaneously run where the 2 solutions (at anode and cathode respectively) are at different concentrations. Lets say that our solutions were 1 M and 0.1 M respectively, but the anode and cathode were not identified. From that information can we instantly deduce that the reaction would move from the lower to higher concentration to make the Nernst eq yield a +E b/c such a rxn is spontaneous? Or does the anode and cathode have to be identified in order to deduce how the cell will run?

thank you for the clarification.

I understand that in terms of proteins, when one denatures them, they tend to assume the primary structure depending on which bonds were broken when the denaturing agent was used. However, what does denaturation mean in terms of DNA? Does it mean that the 2 strands are separated (ie breaking Hydrogen bonds b/w the bases) or does it have another meaning?

I am trying to understand where blood pressure would be the largest. In a book that I was reading, it said that blood would be bigger near the heart (such as in the arms) than in the toes. I could see that being true since the left ventricle has the highest blood pressure in that it must pump blood with enough force for it to constantly circulate throughout the body. However, based on the physics definition of pressure where pressure increases with depth, wouldn't pressure be largest in our toes? Also I have a side quest about pressure and height. If one is comparing the blood pressure of individuals with varying height, the taller person would have a higher blood pressure than the smallest person because the heart must contract with more force to circulate blood, esp to the head. So that is why a giraffe would have a very high blood pressure, compared to see a human (who is shorter).

Thank you both for the clarification. So basically tight junctions are more for preventing particles/proteins/compounds from entering the tissue, while desmosomes just hold cells together-- like squamous epithelial cells. My own research did not yield much clarification except the proteins that construct each of them. Desmosomes are composed of keratin while tight junctions are composed of 2 other proteins. I also found that desmosomes are founds in the heart and mutations in their function can lead to various heart arrhythmias Tight junctions are found in a majority of cells in out body like lining blood vessels and the stomach.

I am trying to understand the difference b/w tight junctions and desmosomes and have yet to find a major physiological one as they are both used for anchoring cells and both are impermeable. Then if they have nearly identical functions then why can't we have desmosomes in GI tract rather than tight junctions or tight junctions in skin rather than desmosomes in the epidermal layer connecting squamous epithelial cells?

I was looking online but I cannot find a good resource that explains the difference b/w desmosomes and tight junctions and the rationale behind their respective locations in the body. It seems to me that they do nearly the same thing. Would someone please be able to clarify. Thank you.

I am trying to understand the purpose of DNAses in eukaryotic cells. I think that they are present as antiviral software to destroy single stranded DNA that is floating around in the cytosol and nucleus. However, DNA is single stranded in the nucleus during replication and transcription but those are not touched or few are degraded. Does DNAse have any other functions in eukaryotic cells that I am missing? Thanks.