welcome redditors!to snoo-finity ... and beyond!
Welcome to blueberrymuffinbabey's page.
Contributor score: 1
School:


Comments ...

 +0  (nbme23#3)

I got this one wrong, but based on the ITT perspective others mentioned, maybe the "in their primary analysis" part of the question is a tip off. They'd start with including them in the original groups and then do additional analysis to try and tease out the impact? IDK





Subcomments ...

submitted by drdoom(369),

Here’s one way to process-of-eliminate “decreased hydrogen-bond formation”: I’m not a big fan of this line of reasoning, but technically alanine as a side group has more hydrogens* for potential hydrogen bonding than glycine:

alanine: —CH3
glycine: —H

So, “technically,” alanine would permit more hydrogen-bond formation, which might allow you to eliminate that choice.

That said, it seems almost impossible to rule out (without very technical knowledge or some provided experimental data) that the slightly larger alanine does not impair hydrogen bonding between collagen molecules via steric (spatial) interference. In simpler terms, since alanine is larger, you would think that it must somehow interfere with the hydrogen-bonding that occurs with the wild-type glycine.

---
*Strictly speaking, it’s not the number of hydrogens but also the strength of the dipole that facilitates hydrogen bonding: a hydrogen bound to a strongly electronegative molecule like fluorine will “appear” more positive and, thus, hydrogen-bond more strongly with a nearby oxygen (compared with a hydrogen connected to carbon, for example).

Further reading:

  1. https://www.chem.purdue.edu/gchelp/liquids/hbond.html
hungrybox  Appreciate the effort but this is far too long to be useful. +7  
drachenx  hungrybox is a freaking hater +  
drdoom  @drachenx haha, nah, coming back to this i realize i was probably over-geeking lol +  
blueberrymuffinbabey  isn't the hydrogen bonding dependent on the hydroxylated proline and lysine? so that wouldn't really be the issue here since those aren't the aas being altered? +  
drdoom  @blueberry According to Alberts’ MBoC (see Tangents at right), hydroxylysine and hydroxyproline contribute hydrogen bonds that form between the chains (“interchain”, as opposed to intra-chain; the chains, of course, are separate polypeptides; that is, separate collagen proteins; and interactions between separate chains [separate polypeptides] is what we call “quaternary structure”; see Tangent above). And in this case, as you point out, the stem describes a Gly->Ala substitution. That seems to mean two things: (1) the three separate collagen polypeptides will not “pack [as] tightly” to form the triple helix (=quaternary structure) we all know and love and (2) proline rings will fail to layer quite as snugly, compromising the helical conformation that defines an alpha chain (=secondary structure; the shapes that form within a single polypeptide). +  


submitted by hungrybox(433),

Macroscopically, squamous cell carcinoma tends to be off-white in color, arising from, and extending into a bronchus.

Source: Radiopedia

privatejoker  Lol am I the only one that picked Malignant Lymphoma? I thought I remembered Sattar mentioning that metastases are the most common form of cancer to be found in the lung? I tend to pick the "most common" presentation when given so little information to work with +  
blueberrymuffinbabey  but metastases typically present with multiple lesions so I think at least in exams when it's showing you a solitary lesion, think a primary tumor. +1  


submitted by diabetes(11),

can somebody explain how energy production by glycolysis increased, since aerobic glycolysis produce 32 net ATP,compare to 2 net ATP through anaerobic glycolysis ?

diabetes  i think the stem should be "energy production by an anaerobic glycolysis " +1  
blueberrymuffinbabey  yeah that's the bit that tripped me up too. i get that there would be increased glycolysis in general to compensate for lack of TCA function but...the fact that it says "energy production by glycolysis" is kind of misleading/confusing. +  
thotcandy  technically, glycolysis is the reaction that happens in the cytosol that generates pyruvate and 2 net ATP. after that it's TCA and Oxidative phosphorylation, which occur in the mitochondria. By definition, glycolysis is anaerobic - which is why they hammer the fact that RBC undergo glycolysis only into our heads. +  
thotcandy  technically, glycolysis is the reaction that happens in the cytosol that generates pyruvate and 2 net ATP. after that it's TCA and Oxidative phosphorylation, which occur in the mitochondria. By definition, glycolysis is anaerobic - which is why they hammer the fact that RBC undergo glycolysis only into our heads. +  
targetmle  i got it wrong because of this as i thought ATP will be decreased in anaerbic glycolysis, but proabably it was mainly 'glycolysis' is increased +  


submitted by ls3076(36),

can anyone explain why (D) metaplasia is incorrect?

angelaq11  because metaplasia would be a transformation of the normal architecture of the respiratory epithelium to one that does not belong there, in response to chronic irritation. This woman had pneumococcal pneumonia that was correctly (and I dare say promptly) treated, so she suffered an acute rather than a chronic insult. +  
blueberrymuffinbabey  because metaplasia isn't how the normal healing/regeneration response happens in the alveoli. the type 2 pneumocytes serve as stem cells/precursors to both type 1 and 2 pneumocytes so the regeneration is not metaplasia. +