BMS 250 Chapter Notes - Chapter 4: Start Codon, Polysome, Release Factor
Document Summary
Other changes: further modification to form the mature mrna include capping and addition of a poly a tail. Capping involves the unique bonding of a ribonucleotide containing guanine to the lead end of the mrna. This increases the stability of an mrna strand helping to prevent its digestion by nucleic acid digesting enzymes that are present within the cytoplasm. The poly a tail addition involves removal of terminal segments of the mrna and placing numerous adenine-containing ribonucleotides at the tail end of the mrna. These nucleotides are subsequently removed over time, and the tail is shortened. When only a certain amount of the tail remains, nuclease enzymes will destroy the mrna. The newly formed mature mrna exits the nucleus following its modification. It leaves through nuclear pores to enter the cytoplasm as it makes its way to ribosome for translation. Translation: is the synthesis of a new protein and takes place at ribosomes within the cytosol.
