RNA RNA ribonucleic acid Three types n Singlestranded
RNA
RNA (ribonucleic acid) Three types n Single-stranded in humans n Contains sugar/phosphate backbone and nitrogenous bases; just like DNA n The sugar this time is ribose n The bases are adenine, cytosine, guanine and uracil n
m. RNA (messenger) Takes DNA ‘message’ out of the nucleus to the cytoplasm n Starts with RNA polymerase (enzyme) that finds the gene to be transcribed from the DNA n
n RNA bases pair up with exposed DNA bases from a start signal code to a stop signal code Each three nucleotides code for an amino acid; on m. RNA this is called a codon n This process is called transcription n
t. RNA (transfer) Involved in protein synthesis n There is one t. RNA for every amino acid (twenty different amino acids = twenty different t. RNA) n Three bases on a t. RNA will bond with each codon on an m. RNA; these bases are called the anticodon n
Pairing occurs while m. RNA is attached to a ribosome (ribosomes read the codons and build the proteins) n t. RNAs come to the ribosomes carrying an amino acid and attach to the corresponding codon n
The amino acid is linked to the growing protein by a peptide bond n Then the ribosome will move down and read the next codon and wait for the next correct t. RNA n This process is called translation since you are translating DNA code into a new language of proteins n
- Slides: 7