I am a mechatronics engineer who stopped learning biology after high school - but this is bothering me.
mRNA is, if I recall correctly, created in the nucleus of the cells and migrates out of the nucleus inside the cytoplasm where it will be translated by ribosomes.
mRNA vaccines inject mRNA molecules inside the body, which are apparently transported by their nanolipidic particle coating across the cell membrane, correct?
I understand that the DNA→mRNA transcription is probably not reversible, but I do not understand how the mRNA is only able to cross the nucleus-cytoplasm membrane in one direction.
Care to explain? Bonus kudos for clarifications on the rest of my doubts.