How many high-energy phosphoanhydride bonds are needed in translation?

[match2011]

tRNA aminoacylation: ATP ---- AMP (2)
initiation: GTP ----- GDP (1)
elongation: GTP ----GDP (1)
translocation: GTP ----GDP (1)
Termination: GTP ---- GDP (1)


Total 6

But FA P75 said 4


Why?

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[Sol Rosenberg]

They're usually asking how
many phosphoanhydride bonds per amino acid, so you wouldn't count the initiation and termination steps. Just 2 to charge the tRNA and 2 to translocate the ribosome. I guess, if you want to get technical, it takes 4n + 2, where n is the number of AA in the polypeptide (and Im taking your word that initiation and termination each consume 1 phosphoanhydride bond.)

 

[match2011]

Thanks.

peptide :

4n?

4(n-1): elongation, translocation, and activated
Met: 3 :activated, initiation,
1 :termination

They're usually asking how
many phosphoanhydride bonds per amino acid, so you wouldn't count the initiation and termination steps. Just 2 to charge the tRNA and 2 to translocate the ribosome. I guess, if you want to get technical, it takes 4n + 2, where n is the number of AA in the polypeptide (and Im taking your word that initiation and termination each consume 1 phosphoanhydride bond.)

 

[username456789]

This is the kind of stuff that will make us all great doctors.

 

[mq123]

This is the kind of stuff that will make us all great doctors.

Or... make someone like me panic because I don't really remember this (did bchem a while back) and wouldn't expect to be tested on little details

 

[MilkmanAl]

This is the kind of stuff that will make us all great doctors.

Dude, I'm going to be calculating all of my patients' free energy all the time so I can keep exact tabs on their metabolic status. It's the next big thing.

These are the types of details I completely ignore. If the NBME is willing to screw me out of a point because I don't know the amount of energy necessary to run a round of translation, I'm over it.

 

[eddie13231]

Dude, I'm going to be calculating all of my patients' free energy all the time so I can keep exact tabs on their metabolic status. It's the next big thing.

These are the types of details I completely ignore. If the NBME is willing to screw me out of a point because I don't know the amount of energy necessary to run a round of translation, I'm over it.

Yep. I definately don't think you need to know this stuff to score well (240+)either. Been doing very well on UW questions and have never been asked ATP stuff.

 

[aashkab]

wouldnt it be 3 bonds?

 

[aashkab]

They're usually asking how
many phosphoanhydride bonds per amino acid, so you wouldn't count the initiation and termination steps. Just 2 to charge the tRNA and 2 to translocate the ribosome. I guess, if you want to get technical, it takes 4n + 2, where n is the number of AA in the polypeptide (and Im taking your word that initiation and termination each consume 1 phosphoanhydride bond.)

wouldn ti be 3 bonds then?

 

[Sol Rosenberg]

wouldn ti be 3 bonds then?

2 + 2 = 4

 

[jackets5]

alot of the questions that i see asked on SDN are questions about things i have never seen on UWorld or on an NBME. like previously said if i get a question like that, ill either hope its experimental or try to make a best quess. IMO, there are much better uses of time than to be memorizing things like that.