# RNS mass calculation question

• lkwarren01
In summary, the mass calculation for strings in the R and NS sectors use a combination of bosonic and fermionic oscillators, even though the R sector contains fermions and the NS sector contains bosons. This is because they are referring to spacetime fermions and bosons, not world-sheet ones.

#### lkwarren01

I'm an engineer trying to get some understanding of string theory. I'm reading the Becker, Becker, & Schwarz book & am confused about the string mass calc in the R & NS sectors. As I understand it, the R sector contains fermions & NS has bosons. Yet, the mass squared in R depends on the sum of bosonic & fermionic oscillator coefficients. Same w/ NS sector. Why not bosonic oscillators only in NS & fermionic oscillators only in R sector for the mass calc?

Thanks to anyone taking the time to read this
Larry Warren
Joliet, IL

lkwarren01 said:
...As I understand it, the R sector contains fermions & NS has bosons. Yet, the mass squared in R depends on the sum of bosonic & fermionic oscillator coefficients. Same w/ NS sector. Why not bosonic oscillators only in NS & fermionic oscillators only in R sector for the mass calc?
They mean spacetime fermions and bosons, not world-sheet fermions and bosons.

## 1. How is the mass of an RNA molecule calculated?

The mass of an RNA molecule is calculated by adding the atomic masses of each of its individual atoms. The atomic masses can be found on the periodic table.

## 2. What is the formula for calculating the mass of an RNA molecule?

The formula for calculating the mass of an RNA molecule is: mass = (A x 329.2) + (C x 305.2) + (G x 345.2) + (U x 306.2) - 61.96, where A, C, G, and U represent the number of adenine, cytosine, guanine, and uracil bases, respectively.

## 3. Are there any other factors that can affect the mass of an RNA molecule?

Yes, there are other factors that can affect the mass of an RNA molecule, such as post-transcriptional modifications, which can add or remove specific chemical groups and alter the mass of the molecule.

## 4. Can the mass of an RNA molecule vary between different organisms?

Yes, the mass of an RNA molecule can vary between different organisms due to genetic differences and variations in the number and types of post-transcriptional modifications.

## 5. How accurate is the calculated mass of an RNA molecule?

The calculated mass of an RNA molecule is usually accurate to within a few decimal places. However, the accuracy can be affected by factors such as experimental error, sample contamination, and the presence of post-transcriptional modifications.