CharonY

Or it is simply due to evolutionary history. Our ancestor happened to be bilateral symmetric and that build plan was quite successful among the animalia (i.e. more phyla than in porifera and radiata). From a developmental viewpoint I would think once the general development was comitted towards bilateralism there was little in the way of alternatives. However, a evolutionary biologist or someone from evo-devo is likely to have a better answer to the question. Ultimately it is obviously not something that we can look for in one species (e.g. humans) but we would have to look way back into our evolutionary history.

There is quite a difference, though. In religious faith you have to accept a (often complex) doctrine at face value and never question it. In biology you do not have faith in abiogenesis. Instead there ware some fundamental aspects that all evidence point to. The first is that all organisms are related. Considering what we do know about evolution there is strong evidence that we therefore have to have a common ancestor of sorts (there may have been more, but if they existed they vanished without leaving identifiable traces).The question is now how did the original organims develop, the core of abiogenesis, if you will. The whole discussion is based on known (or newly identified) molecular processes that may pertain to that (such as enzymatic functions and replicating abilities in very simple molecules). There is no complete doctrine given at face value that you will have to subscribe to, as in a religious context. Instead, we have questions. Lots of them. Nothing is dependent on faith. Why then are religious theories mostly not considered? Well, based on our biochemical knowledge highly complex structures can arise from very simple molecules (remember, every whale was a single cell once). So the hypothesis that some analogous may have led to the first cell is something that you can investigate and test. On the other hand, assuming it just appeared supernaturally is not testable and therefore requires a leap of faith to fully accept it.

Considering the nature of the loading buffer and the heat denaturation plus further dilution after coming in contact with eye fluids risks of actually having intact particles are very low. But even so I would always ask students (especially beginners) to treat everything as highly infectious. Simply as part of the training. You will get sloppier at some point anyway, may as well start out with a higher standard.

As ajb said (and mentioned in OP), in most areas of Europe the curricula are more specialized. How easy it is to switch or start over completely varies from university and may also depend on tuition fees (if they exist). One way I would go about it is to buy/borrow a well-rounded overview textbook for each topic and read them. Does any of it seems to be more interesting to you than the other (viewpoint wise)? Another aspect would be based on career choices, but they are often hard to make that early on. I would generally also avoid making the decision based on something such as math. it is a tool in physics but so are all the other things that you will have to learn in any discipline (if you want to become competent that is).

Based on the description the actual risk appears to be low. Nonetheless, incidents like this have to be reported and documented for your own safety as according to biosafety regulations (in most countries, I presume). That being said it should be noted that it sounds to me that several safe regulations are not being followed in your lab. The first is that every member of a lab (regardless whether student or staff) has to be informed on all potential biosafety hazards as well as risk assessment and safety procedure. I am aware this is sometimes done in a lax way, but considering that you have not immediately notified the incident appears that you have not been well informed. This is not to admonish you, but just to give you basic information on lab safety issues. On the same note, all work with lentiviruses (as well as human cell lines for that matter) are automatically biosafety level 2, which also means that personal protection has to be used at all time. Technically this is also true for biosafety level 1 but people usually start to get really serious at 2. So while doing work that can generate splashes or aerosol face protection (goggles) have to be worn. For your own protection, review the safety procedures, even if others may not follow them. In the end everyone is responsible for his/her own safety, even if the PI make think differently.

I agree that it may be expressed a bit confusingly. As mentioned basically all metabolic reactions are reversible, irreversibility usually takes into account the physiological conditions (more or less). Some reactions that are reversible in vitro, may always be irreversible in vivo. But first, as already mentioned the important bit is the changes of Gibb's free energy, which is related to the equilibrium constant K. Thus at equilibrium for a simple reaction [latex]K= \frac{Product}{Reactant} [/latex]. How does K relate to the rates of the individual reaction k? Well: [latex]K= \frac{ k_{forward} }{k_{back}} [/latex] So obviously for reactions that go towards completion the forward reaction rate is higher than the return reaction. This seems to be the issue that is mentioned in OP. However one possibility to resolve this is a view at the whole pathway. Here we do not have a single reaction but many out- and influxes into the reaction under investigation. If subsequent reaction rates (or outflows) are higher than the first reaction, we are not in an equilibrium situation anymore. Even with a relatively low K we may get directionality in the metabolite flow. One may take the hexokinase reaction in, say yeast or other eukaryotes (glucose -> glucose-6P) which (if memory serves) has a K of well below 1000. However the concentration of glucose is generally way higher than that of the phosphorylated product. Hence, a reverse reaction is usually not observed.

For simple immobilization e.g. for ELISA? In most cases adsorption is sufficient on materials such as polystyrene. There are ways to improve it by surface activation or incorporation of linkers. Depends on the purpose.

As mentioned, cancer is essentially not a disease per se, but rather a systemic issue with the way our cells propagate themselves. There will be no simple cure just a hope that we will find something that kills those cells more efficiently than others. Even today, more focused approaches are not that selective and have mostly been shown to be effective in cultures. In whole organisms or even tissues it will be quite difficult and is likely to cause severe damage (but hopefully less than full-blown chemo). In addition to cell-type specificity there is also the issue of delivery, for example. HIV has the issue that the parts being identified by our immune system change a lot so that vaccinations generally do not work. I have heard of some progress in that area, though.

I do not understand your question. The alternative name for leucine is 2-Amino-4-methylpentanoic acid. In addition UUC codes for phenylalanin. Leucine is coded by UUA UUG CUU CUC CUA CUG .

There are probably too many issues to list them comprehensively but things that pop into my mind are: - we do not know how precisely the proteins have to work together to result in a specific phenotype. The interplay of the components is very intricate, and quantitative (i.e. it is not a on/off situation but rather requires a delicate balance) - even if we knew the components and the required equilibria, we do not know how to carefully balance them out. Most genetic manipulations are very heavy-handed - even if we could do that, we lack the means to to so coordinated in a large number of cell (e.g. within a tissue) - even if we could do that, there is a chance that we disrupt existing functions. No metabolic activity happens in isolation. If you tweak things on one end, a lot of further elements are getting affected. While we are starting to developing techniques to monitor it (on the cellular level) we still lack a comprehensive view of all the events and their consequences on a more complex level. In short, we do not know enough.

How? By starting yet another war that the US could not really afford? How else could he support the uprising? Also, similarly to the US those anti-Assad are not necessarily pro-US, which makes taking sides quite tricky. That being said: The Syrian government has accepted a Russian proposal to put its chemical weapons under international control to avoid a possible U.S. military strike, Interfax news agency quoted Syria's foreign minister as saying on Tuesday.

The general notation for DNA is usually the 5' to 3' (e.g. TGAGACCTGAAGA). The complementary strand is usually not indicated as the pairing rules make it obvious what it would be. There is no way to know what goes next based on a short string unless you know where it originated from, as said above.

Yes, certainly. The enzyme may degrade over time, but that can also happen quite quickly if protease contamination is present. Even at -20 enzymes lose quite a bit of their efficiency, which can be accelerated quite a bit buy freeze-thaw cycles.

Uh, but if a non-tattooed person does not care, does it make him/her tattooed?

Good analytical chemistry classes are usually also more instrumental, especially if the include bioanalytical techniques. I.e. instead of basic chemistry it will be much more focused on how it can be exploited e.g. for differentiation of molecules.

Reading through the wiki articles should be a good basis. In addition, you really have to be clear for what the internal standard is being used. Depending on whether it is for normalize elution time or signal area, for example. In some cases an external standard is much more useful.

Are you using UV detection or MS? If it is only UV you cannot use the same compound as internal standard since, as you pointed out, you would measure the combined amount of sample+standard. In an MS you would use an isotope labeled compound where you could distinguish standard from sample. Instead you can only use an internal standard (to judge the run quality) that is a different compound not found in the tissue. To your questions: 1) You would generally use a matrix that is similar to your sample (ideally leaf tissue that is completely free of SA) and spike it with the known amount. Alternatively you can make a baseline subtraction (i.e. measuring the base SA level and compare it to the spiked sample). The latter is a bit less reliable, though. The recovery rate is then based on the area of a pure SA sample (i.e. you do three runs, pure SA, spiked sample, pure sample). There can be an additional error introduced by the sample prep itself, if e.g. additional UV absorbing components are present. 2) Yes, hence you also to run non-spiked samples.

It indeed refers to the insertion or deletion of a base at that position (so either absence or presence of an additional G) on the respective chromsome (remember, we are diploid).

For complex multicellular organisms unlikely, at least in the way described. That being said, horizontal gene transfer is quite common and is a major force in evolution. It would not be a directed response to a stimulus though (i.e. developing heat resistance after sensing heat). Instead after acquisition of external DNA either from other organisms (e.g. via mobile genetic elements) or from the environment (i.e. via transformation) would be more or less random-ish (i.e. transfer rate is independent of phenotype) but could be selected for due to the environmental pressure. Another analogy is the error-prone repair mechanisms of some single organisms, in which case the mutation rate is higher under stress.

I think this is not the point. What is being wrong, if the bottom line is similar? Also it has not been established that it would be better (or worse) without the EU. To me there is a lot of opinion in this thread, but almost no data to support them. Also if debt is any indicator of good policy then we should promptly copy, say, Iran (about 1% government debt as % GDP). Or Sweden (-17%!). Wait no, Sweden is being destroyed by the EU.

Ouch no, that is wrong. I appreciate your enthusiasm but please do not post guessworks and proclaim them to be facts. You may confuse people. Endorphin is a summary term for endogeneous peptides that bind to opiate receptors. What OP is referring to is probably the difference between alpha-endorphin (a specific peptide in that group) and alpha-neoendorphin. The former being a peptide with the sequence Tyr-Gly-Gly-Phe-Met-Thr-Ser-Glu-Lys-Ser-Gln-Thr-Pro-Leu-Val-Thr and the latter Tyr-Gly-Gly-Phe-Leu-Arg-Lys-Tyr-Pro-Lys. Proenkephalin B the precursor of alpha-neoendorphin is way larger (254 AA). Generally, peptide and protein nomenclature does not follow the same rules as other, smaller C-bodies and can be a bit confusing at times. Even worse, many have several names, depending how it was identified and characterized.

I think in this context it is relevant to note that politicians in other countries have pushed for a similar control over science, including the US and Canada. http://news.sciencemag.org/2013/04/u.s.-lawmaker-proposes-new-criteria-choosing-nsf-grants http://business.financialpost.com/2013/05/14/how-should-science-research-funding-be-determined/?__lsa=d350-a2a2 In several grant mechanisms in Canada you have to submit the direct benefits (in terms of health or economy for Canada) of your proposed research. These things cripple fundamental sciences, of course. There is also a general push towards sustainability of programs, i.e. the research is supposed to generate revenue to finance itself, again something that is virtually impossible for basic research. Considering that almost the only source of basic research are government funding, this paint a very bleak view for the future of discoveries.

To be fair, from the description it does not really look like that religion is prime reason, rather that one being a dick and the other one having lack of self control (and too much drugs and booze).

I assume you are aware that these criteria are neither universal nor undisputed and essentially is descriptive? I.e. the definition is essentially derived by first declaring something to be alive (i.e. cell) and then distinguish it from everything else.

There is a push towards open source publishing. However, many prestigious journals are still in the hands of publishing companies that want to turn a profit. Note that the scientists actually have to be pay for publishing and in some cases open source journals are more expensive. Some for-profit journals are actually free to publish in, if you do not include color prints, for example. Obviously, most scientists would be happier if more people could read their work. but sometimes budget constraints are very, very tough.