NS 6

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can you explain this question ? what do you mean derive an amide from a relic acid?
thank you ) @Next Step Tutor

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how do you do this problem fast? i knew all the info. i knew how to do it. but the math was taking forever so i skipped it.

 

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how do you solve it faster?

 

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for this question. are you missing an L in the numerator .. if this is a mistake, it just wastes my time

@Next Step Tutor

 

[NextStepTutor_1]

Hi @AnteaterPediatrician,

Going question by question:

#6: The idea here is that oleic acid, shown in Fig. 1, is a carboxylic acid, the question boils down to how do you get an amide from a carboxylic acid. The underlying concept has to do with the hierarchy of relative reactivities of carboxylic acids and their derivates, which you can find a quick online review of here. Basically, you can't just make an amide from a carboxylic acid, you have to convert it to something more reactive first, and an acid chloride (which you would obtain via treatment w/ phosphorus pentachloride -- even if you don't know this reagent, chloride is the key tip) would do the trick.

#14: There's not really a quick shortcut here. The trick to do well on these questions is to thoroughly review and practice these kinds of stoichiometric calculations so that they become instinctual and you don't have to invest a lot of time in setting them up. Note that there are basically two steps here: (1) find how many grams were administered; (2) convert grams to moles. The quicker you can set up those higher-level steps, the more likely you will be able to efficiently deal w/ complications like the difference between hematoporphyrin and porfirmer.

#50: Similar deal -- there's no way to avoid the calculations. I see that you picked (B), which is what you get if you do everything correctly up until the very last step of solving for the total stretched length, not the displacement. This is a useful reminder to double-check that the answer you get is exactly what the question is asking for, b/c it's really easy to get caught up in calculations and forget to cross-reference.

#56: The key for this question is realizing that you can ignore everything but the term (P1 - P2) = 3(P2 - P3) .

Hope this is helpful!

 

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Made a mistake here right. The water flows out from descending not ascending

 

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Continued

 

[NextStepTutor_1]

Yes, it looks like there's a typo there at the end of the 'correct answer' explanation (although the beginning of the statement does correctly state that the descending loop is permeable to water). Thanks for pointing it out, we'll make a note to fix it!

 

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thank you. can you also please help me with these questions. I asked this last time but no one ws able to help. how come acetyl co A will not work. it seems like it is a precursor. @NextStepTutor_1

 

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how come it is glucagon?

 

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How is alpha ketogluteate work. Doesn't seem to convert to glucose

 

[NextStepTutor_1]

Hi AnteaterPediatrician:

For Q81, the Wikipedia article on gluconeogenesis, especially the section on precursors, actually does provide a pretty decent review of this. To respond to your questions more specifically, the issue regarding acetyl-CoA is that just b/c acetyl-CoA is made from pyruvate doesn't mean that you can effectively reverse the process and make pyruvate from acetyl-CoA. The conversion of pyruvate to acetyl-CoA takes place at the pyruvate dehydrogenase complex, is highly regulated, and can't simply be reversed under most conditions. This is actually a really important point to keep in mind when studying pathways. For alpha-ketoglutarate, the idea is that all intermediates of the citric acid cycle can ultimately feed gluconeogenesis because they can be converted to oxaloacetate, which is the more direct precursor.

For Q83, the key is to read the third paragraph, where the passage specifically talks about infants who received an oversupply of blood glucose during fetal development. This paragraph states that their hormonal environment inhibits the rate of glucose released from the liver, so endogenous stores need to be mobilized. Glucagon will do the job because it causes more glucose to be released into the bloodstream.

Hope this is helpful & best of luck!

 

[Squish miss]

Hi AnteaterPediatrician:

For Q81, the Wikipedia article on gluconeogenesis, especially the section on precursors, actually does provide a pretty decent review of this. To respond to your questions more specifically, the issue regarding acetyl-CoA is that just b/c acetyl-CoA is made from pyruvate doesn't mean that you can effectively reverse the process and make pyruvate from acetyl-CoA. The conversion of pyruvate to acetyl-CoA takes place at the pyruvate dehydrogenase complex, is highly regulated, and can't simply be reversed under most conditions. This is actually a really important point to keep in mind when studying pathways. For alpha-ketoglutarate, the idea is that all intermediates of the citric acid cycle can ultimately feed gluconeogenesis because they can be converted to oxaloacetate, which is the more direct precursor.

For Q83, the key is to read the third paragraph, where the passage specifically talks about infants who received an oversupply of blood glucose during fetal development. This paragraph states that their hormonal environment inhibits the rate of glucose released from the liver, so endogenous stores need to be mobilized. Glucagon will do the job because it causes more glucose to be released into the bloodstream.

Hope this is helpful & best of luck!

thank you. i have a question on electrolytic.
is a galvanic and battery cell and voltaic cell the same/
and where do the anions and cations go in a gel electrophoresis vs a battery cell and why. kind of confused still. thought i had it

 

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I thought in a battery cell/galvonic , the anode is where the cations go but this says otherwise
https://upload.wikimedia.org/wikipe...g/400px-Galvanic_cell_with_no_cation_flow.png

thank you @NextStepTutor_3

 

[NextStepTutor_1]

Hi AnteaterPediatrician,

To answer your first question, yes, galvanic and voltaic cells are two names for the same thing. This resource has a good overview of electrolytic cells. In terms of charge conventions, it can be helpful to think about the physical setups. In an electrolytic cell, the electrodes are literally hooked up to a battery, with the anode connected to the positive side and the cathode to the negative side. This is why we say that the anode is positive and the cathode is negative in electrolytic cells. In galvanic/voltaic cells, you have to remember that spontaneous half-reactions occur at the electrodes. At the anode, constant oxidation processes mean that a bunch of electrons are always appearing around the anode, which is why we consider it negative.

Hope this is helpful & best of luck!