The form of RNA that your are referring to is tRNA. tRNA stands for t(ransfer) R(ibosomal) N(ucleic) A(cid). tRNA transports amino acids to the ribosome during protein synthesis.
tRNA is a molecule synthesized from the process of transcribing DNA into segments located in specific regions of chromosomes. It is involved with protein synthesis in the mechanism of gene translation.
This molecule is responsible for driving amino acids to form the polypeptide chains that make up proteins. Its role in gene translation can be understood by parts:
The mRNA (messenger RNA), bringing the DNA coding for protein synthesis, is associated with the smaller ribosome subunit. This ribosome will traverse the ends of mRNA, catalyzing the union of amino acids.
Each tRNA, carrying a specific amino acid, binds to the mRNA codons through its anticodons. The tRNA that initiates protein synthesis is what transports methionine. Its anticodon has the UAC sequence, so it binds to the mRNA codon AUG sequence. In the same way, the other tRNAs fit their amino acids, which, by ribosome action, are joined by peptide bonds.
As the ribosome “glides” over the mRNA molecule, the amino acids brought by the tRNA bind in each predecessor and are carried by the ribosome until it arrives at a stop codon.
By the end of this process, the amino acids brought by the tRNA will then have formed the polypeptide chain. The mRNAs, ribosomes and tRNAs participating in the process separate and the formed protein is released.
They do not have a cell wall because only plant cells have that. The plant cells have that to help with the process for creating the green color. The animal cells, instead, they have a cell membrane.
