Page 98 - Medicinal Plants_PharmD general

Protein biosynthesis in plants consists of two major steps (Figure
31). The first step is the transcription of DNA into RNA and the second
step is the translation of RNA into protein.

Figure 31. Biosynthesis of proteins
The detailed biosynthesis process can be summarized as follows:
1. DNA in the nucleus directs the synthesis of messenger RNA (mRNA)

and provides it with necessary genetic information in the form of codons
for the formation of specific proteins. This process is called
transcription. The type, structure and function of the protein depends on
the result of the translation of the genetic code on mRNA.
2. mRNA molecule moves into the cytoplasm where it causes formation
of specific transport RNA (tRNA) molecules having specific anticodons
complementary to the mRNA codons.
3. mRNA becomes associated with the ribosome which acts as template
for protein synthesis. At this template energy is supplied by GTP
(Guanosine triphosphate). Mg++ ions are also required.

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