Need help

[Xylitol]

You want to use a radioactive tracer that will label only the protein in an RNA virus. Assume the virus is composed of only a protein coat and an RNA core. Which of the following would you use? Be sure to explain your answer.

a. Radioactive P
b. Radioactive N
c. Radioactive S
d. Radioactive C

I have no idea.
proteins are amino acids which are made up of C and N
rna is nucleotides made up of P, N, C

I mean if it was asking for me to identify only the RNA, I would say radioactive P, but that's not the case...

Anyone know?

 

[Brainonska511]

If you know the coat contains cysteine or methionine, you could use S.

If you want to identify both, it depends on how the material is introduced as carbon can do different things based on how it enters the cell.

N would be useful in that it is found in both RNA and amino acids. It might be the best one to use. For purines and pyridimines (within the primary ring, not the A/G/T/U substructure), the N comes from glutamine (which can easily be synthesized from glutamate and glutamate is the product after amino acids are broken down upon entry through the exchange process with keto-acids) And that glutamate or the .

 

[Xylitol]

Originally posted by: Brainonska511
If you know the coat contains cysteine or methionine, you could use S.

If you want to identify both, it depends on how the material is introduced as carbon can do different things based on how it enters the cell.

N would be useful in that it is found in both RNA and amino acids. It might be the best one to use. For purines and pyridimines, the N comes from glutamine (which can easily be synthesized from glutamate and glutamate is the product after amino acids are broken down upon entry through the exchange process with keto-acids).

But if I'm only trying to identify the protein and since this is a multiple choice question, then S would probably be my best bet right (since all the other things are either common in both protein/RNA or only in RNA)

 

[Brainonska511]

Originally posted by: Xylitol

Originally posted by: Brainonska511
If you know the coat contains cysteine or methionine, you could use S.

If you want to identify both, it depends on how the material is introduced as carbon can do different things based on how it enters the cell.

N would be useful in that it is found in both RNA and amino acids. It might be the best one to use. For purines and pyridimines, the N comes from glutamine (which can easily be synthesized from glutamate and glutamate is the product after amino acids are broken down upon entry through the exchange process with keto-acids).

But if I'm only trying to identify the protein and since this is a multiple choice question, then S would probably be my best bet right (since all the other things are either common in both protein/RNA or only in RNA)

Yeah - if you're only trying to find the protein coat, I would say tagging S would be the best bet, but that's assuming the coat uses cys or met. All the other elements are not found in proteins or are found in both RNA and proteins. If you wanted to find both, N is the best bet.

 

[Ticky]

Originally posted by: Brainonska511
If you know the coat contains cysteine or methionine, you could use S.

If you want to identify both, it depends on how the material is introduced as carbon can do different things based on how it enters the cell.

N would be useful in that it is found in both RNA and amino acids. It might be the best one to use. For purines and pyridimines (within the primary ring, not the A/G/T/U substructure), the N comes from glutamine (which can easily be synthesized from glutamate and glutamate is the product after amino acids are broken down upon entry through the exchange process with keto-acids) And that glutamate or the .

Yeah, I'd say S. I think you're supposed to assume the protein coat contains sulfur-containing amino acids, and the RNA has no sulfur.

 

[summit]

no you would use radioactive p. radio active p would tag the entire nucleotide. by elimination you could determine the protein area if i remember correctly.

 

[Ticky]

Originally posted by: Summit
no you would use radioactive p. radio active p would tag the entire nucleotide. by elimination you could determine the protein area if i remember correctly.

But you want to tag the protein... not the RNA. What's wrong with tagging the S?

 

[Brainonska511]

Originally posted by: Summit
no you would use radioactive p. radio active p would tag the entire nucleotide. by elimination you could determine the protein area if i remember correctly.

If the OP worded the question properly:

You want to use a radioactive tracer that will label only the protein in an RNA virus.

Labeling by elimination is not an option, as the question states "label only the protein."

 

[summit]

well label means identify imo. you might not be able to use S since you dont know the protein coat?

 

[SirStev0]

This is actually based on the way they determined what the code carrying components of cells were (before they had fancy electron microscopes and all the other gadgets.)

It is called the Hershey-Chase Experiment

There are never Sulfurs in nucleotides but there are a two amino acids that have sulfurs and there are rarely phosphates on proteins but there are tons associated DNA and RNA. They labeled cells and saw what was being transferred. Could see it was the Radioactive phosphate and figured out that Nucleotides moved and carried genetic codes.

 

[summit]

Originally posted by: SirStev0
This is actually based on the way they determined what the code carrying components of cells were (before they had fancy electron microscopes and all the other gadgets.)

It is called the Hershey-Chase Experiment

There are never Sulfurs in nucleotides but there are a two amino acids that have sulfurs and there are rarely phosphates on proteins but there are tons associated DNA and RNA. They labeled cells and saw what was being transferred. Could see it was the Radioactive phosphate and figured out that Nucleotides moved and carried genetic codes.

2 years out of the loop. :beer:

 

[Brainonska511]

Originally posted by: Summit
no you would use radioactive p. radio active p would tag the entire nucleotide. by elimination you could determine the protein area if i remember correctly.

But if you label the RNA with the radioactive P, you won't be able to see anything as the whole cell-virus factory will light up. It won't show you where the virus protein coat is.

 

[SirStev0]

Originally posted by: Summit

Originally posted by: SirStev0
This is actually based on the way they determined what the code carrying components of cells were (before they had fancy electron microscopes and all the other gadgets.)

It is called the Hershey-Chase Experiment

There are never Sulfurs in nucleotides but there are a two amino acids that have sulfurs and there are rarely phosphates on proteins but there are tons associated DNA and RNA. They labeled cells and saw what was being transferred. Could see it was the Radioactive phosphate and figured out that Nucleotides moved and carried genetic codes.

2 years out of the loop. :beer:

huh?

 

[Brainonska511]

Originally posted by: SirStev0

Originally posted by: Summit

Originally posted by: SirStev0
This is actually based on the way they determined what the code carrying components of cells were (before they had fancy electron microscopes and all the other gadgets.)

It is called the Hershey-Chase Experiment

There are never Sulfurs in nucleotides but there are a two amino acids that have sulfurs and there are rarely phosphates on proteins but there are tons associated DNA and RNA. They labeled cells and saw what was being transferred. Could see it was the Radioactive phosphate and figured out that Nucleotides moved and carried genetic codes.

2 years out of the loop. :beer:

huh?

I assume it's 2 years since an intro biochemistry class.

It's only been a few months for me, but cellular biochemistry isn't really my strong point. I'm a bigger fan of the chemistry of proteins (and synthetically making them in the lab).

 

[SirStev0]

Originally posted by: Brainonska511

Originally posted by: SirStev0

Originally posted by: Summit

Originally posted by: SirStev0
This is actually based on the way they determined what the code carrying components of cells were (before they had fancy electron microscopes and all the other gadgets.)

It is called the Hershey-Chase Experiment

There are never Sulfurs in nucleotides but there are a two amino acids that have sulfurs and there are rarely phosphates on proteins but there are tons associated DNA and RNA. They labeled cells and saw what was being transferred. Could see it was the Radioactive phosphate and figured out that Nucleotides moved and carried genetic codes.

2 years out of the loop. :beer:

huh?

I assume it's 2 years since an intro biochemistry class.

It's only been a few months for me, but cellular biochemistry isn't really my strong point. I'm a bigger fan of the chemistry of proteins (and synthetically making them in the lab).

ohh..

Btw OP? what type of class is this for. If it is an intro-ish class and one of first few days, I would think that you are almost over thinking it. I am sure the main point they want to make is that both have carbon and nitrogen, but one can contain sulfur and the other can contain phosphorus (in the form of phosphates).