I have to write an essay on how proteins are made in a cell and i need help !?
what happens ?
Every cell has a full set of 46 chromosomes, which contain the DNA needed to ‘code for’ each protein (these are located in the nucleus of a cell). What happens is a process called “the Flow of Biological Information.” It starts with ‘replication,’ in which the DNA makes a copy of itself. (You do not have to worry about this one if you’re only talking about proteins–it becomes more important during cell division. However, it might impress the teacher if you at least mention it in passing.) Next is ‘transcription,’ which is the first big step in protein synthesis. During transcription, the DNA double helix is split down the middle so that an RNA molecule can come and ‘copy’ it, developing nitrogen bases that counterpart the ones in the DNA.
[Extra info: Why can’t the DNA build the protein by itself without the RNA? Protein synthesis occurs in the ribosomes, outside of the nucleus of the cell. The DNA, though, is too big to leave the nucleus. RNA is just the right size to travel in and out of the nuclear membrane, easily transmitting the message from the DNA to the ribosome. Make sense?] The RNA (at this point referred to as ‘mRNA,’ or ‘messanger RNA,’ makes its way out of the nucleus and to a ribosome, (composed of rRNA) which will provide a site for protein synthesis. Here is where the final step for “protein making” comes in: translation.
Now, in the ribosome are even MORE RNA, called tRNA. Attached to each tRNA is an amino acid, the ‘building blocks’ of proteins. These tRNA’s line up with the mRNA’s coded message, assembling the amino acids into just the right order to create the correct protein. The amino acids fuse together with ‘peptide bonds,’ and finally, you have a protein.
The process may seem lengthy and confusing, but considering we can’t live without it…who can complain? 🙂 Hope that helped!