BabcockHall

@OP, This is the second thread (which I have seen) where you have basically dumped a question and expected an answer, which is contrary to forum policy. Please show your work, and we can explain where you went wrong, provide hints, etc.

student, The rules here are essentially that we help you, not that we do your work for you. A good place to start is for you to tell us what you already know.

Maybe you mean nucleolus.

@OP, When you post a question, please give us what you have done so far and your thoughts, as opposed to dumping a problem. However, it is clear from your later comments that you have done some searching.

If the reading produced a very low value of absorbance, it might not be trustworthy, and the measurement should be repeated if possible. I would reach the same conclusion if its value is lower than the lowest value of the standard curve, because interpolations are generally better than extrapolations. Setting aside issues of accuracy, I have found that being consistent in the way that I handle dilutions is helpful to avoid errors. I would calculate a value of the concentration from the standard curve (let's call this C1). Then I would calculate the concentration of the starting solution (C2) using C1(V1) = C2(V2). That is where the tenfold comes in. A common error is to use incorrect values of V1 and V2.

Good points. I would also like to add that the cooperativity of hydrogen bonding and base stacking as something that is worth pondering.

There is a table in Miesfield and McEvoy's biochemistry textbook that indicates that certain base stacking interactions among G:C base pairs are much stronger than the same interaction in certain A:T base pairs. This subject is more complex than I thought it was.

Please show your attempt so that we can help you.

A fair point, and perhaps I should have added that in the presence 5.2 M betaine, the % composition of AT vs GC doesn't affect Tm: PH Von Hippel and collaborators Biochemistry 1993 32, p. 137.

I thought you said that we did not need to go into folding. If we do, then I would ask, "What protein folding problem?" It is an empirical observation that proteins fold quickly; Levinthal's paradox is a fine place to begin thinking about folding, but I don't see it as more than that.

One more thought: Given that the percentage of GC base pairs is positively related to the T(m) of duplex DNA, hydrogen bonds would seem to have some role.

This is a very big topic, too big to do full justice. If you have not consulted a good biochemistry textbook or two, that would help. Here are a few quick thoughts. One, hydrogen bonding is important, owing to the chelate effect. To satisfy the same hydrogen bonds with water as are satisfied with complementary DNA, a large number of water molecules would have to lose translational entropy. Two, according to one textbook, base stacking is driven by enthalpy and opposed by entropy. Therefore, it is unlike a textbook hydrophobic effect. Unlike hydrogen bonding, base stacking is not a highly cooperative interaction. I have heard that both H-bonding and base stacking make about the same magnitude of contribution to the stability of the double helix. My understanding is that there is base stacking in single stranded nucleic acids, but that the process of stacking is not highly cooperative, unlike H-bonding.

Yes, pyruvate can be converted into glucose by gluconeogenesis. Another way to think about alanine and gluconeogenesis is to ponder the similarities of lactate versus alanine. For example both can be converted into pyruvate in one step. EDT You might want to look up the glucose-alanine cycle in your textbook.

Introductory and intermediate laboratory books on organic chemistry sometimes cover this topic. For the example you gave, it would be difficult to put all of them into the correct order a priori. However, sometimes one can use general knowledge about intermolecular forces and general notions of polarity. For example, if I had two compounds that were nearly identical and one could donate a H-bond and the other could not, the one that can donate a H-bond is more polar and will have the lower Rf on silica. Of the compounds you listed, which one do you think would have the highest Rf and why?

I agree that glutamate can be dehydrogenated and the ammonia will enter the urea cycle. This allows the alpha-ketoglutarate to pick up additional amino groups from other amino acids to be degraded (although some could also enter into gluconeogenesis). What do you think that the fate of pyruvate (generated from alanine) is?

Would you mind defining ALT? I will assume that it is an aminotransferase. IMO your assumption about alpha-ketoglutarate is not correct: alpha-ketoglutarate will be converted into glutamate by the transamination that converts alanine into pyruvate. When the body has to use amino acids as fuel, something has to happen to the nitrogen. What is it? Your answer to this question should help answer your question.

Some algae and other microorganisms can produce up to 50% of their mass as oils. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3152439/

Preview the material before the lectures. If you know where you are going, you can structure the material more effectively in your thinking. When you study, avoid distractions.

IIUC party line is that plants store energy as sucrose or as starch. Certain eukaryotic microorganisms can store energy as triacylglycerols. IIRC there was some interest in making biodiesel using these organisms at one time.

One needs to specify whether we are talking about bacteria or humans. The generally accepted number for humans is 30-32 ATP per glucose, as John Cuthber's link provides. The reason that there is uncertainty is that there are more than one ways to move the electrons of cytoplasmic NADH into the mitochondria. IIRC in bacteria, the number of ATP per glucose is slightly higher and may be 36.

Chlorine is much larger than boron. I am not sure that its orbitals will overlap effectively with the orbitals of boron.

How much molar excess ion exchange resin did you use? Which resin did you use? Bromide binds a little bit more strongly to some exchangers than chloride does, so that fact should help the exchange.

What are you thoughts? We cannot help you until you show us what yo have done so far.

From the abstract by Ballantyne and coworkers, "However, safety testing revealed that the combination of hypochlorite and ethanol produced levels of gaseous chlorine at or above the recommended exposure limits. Subsequently, a cleaning protocol of 1% hypochlorite followed by distilled water was tested for efficacy, and subsequently introduced throughout the laboratory." This is an interesting question. Oxidation of an alcohol by hypochlorite should produce chloride ion, as opposed to chlorine gas. http://organic.chem.tamu.edu/Prelab.PowerPoints/Printed%20Slides%20-%20237/Oxidation%20of%20a%20Secondary%20Alcohol-12c.pdf

Bleach is sometimes used to decontaminate prior to performing PCR amplification of DNA. Some protocols used 70% ethanol afterwards, but this releases chlorine gas: http://www.tandfonline.com/doi/abs/10.1080/00450618.2015.1004195?src=recsys&journalCode=tajf20