(b) Structure and functions of RNA. Single strand, replacement of thymine with uracil and deoxyribose with ribose compared to DNA. mRNA (messenger) carries a copy of the DNA code from the nucleus to the ribosome. rRNA (ribosomal) and proteins form the ribosome. Each tRNA (transfer) carries a specific amino acid.
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RNA is a type of nucleic acid similar to DNA. However there are three key differences between RNA and DNA:
1. The sugar in RNA is ribose, not the deoxyribose in DNA (as we previously learned).
2. The base uracil is present in RNA instead of thymine.
3. RNA is a single stranded molecule, DNA is double stranded.
Three main types of RNA exist all involved in protein synthesis.
Ribosomal RNA or rRNA is found in the ribosomes, where protein synthesis takes place. Each ribosome is a complex consisting of about 60% ribosomal RNA (rRNA) and 40% protein.
Messenger RNA or mRNA carries a copy of the information (or transcript) from DNA in the nucleus to the ribosomes. It is this transcript that is used in protein synthesis.
Transfer RNA or tRNA delivers amino acids to the ribosome, where they are inorporated into the growing protein chain. There is a different tRNA for each type of amino acide used in protein synthesis.
