the synthesis stage (s phase) is called synthesis because of export, and translation.
the synthesis stage (s phase) is called synthesis because of export, and translation.
why is the synthesis stage (s phase) called synthesis?
export, and translation
cdk2 is active during g and s phase of the cell cycle, and therefore acts as a g-s phase checkpoint control. prior to g phase, levels of cdk4 and cdk6 increase along with cyclin d. this allows for the partial phosphorylation of rb, and partial activation of e2f at the beginning of g phase, which promotes cyclin e synthesis and increased cdk2 activity. at the end of g phase, the cdk2/cyclin e complex reaches maximum activity and plays a significant role in the initiation of s phase. other non-cdk proteins also become active during the g-s phase transition. for example, the retinoblastoma (rb) and p27 proteins are phosphorylated by cdk2 – cyclin a/e complexes, fully deactivating them. this allows e2f transcription factors to express genes that promote entry into s phase where dna is replicated prior to division. additionally, npat, a known substrate of the cdk2-cyclin e complex, functions to activate histone gene transcription when phosphorylated. this increases the synthesis of histone proteins (the major protein component of chromatin), and subsequently supports the dna replication stage of the cell cycle. finally, at the end of s phase, the ubiquitin proteasome degrades cyclin e.
cyclin-dependent kinase 2
fischer–tropsch plants associated with coal or related solid feedstocks (sources of carbon) must first convert the solid fuel into gaseous reactants, "i.e.", co, h, and alkanes. this conversion is called gasification and the product is called synthesis gas ("syngas"). synthesis gas obtained from coal gasification tends to have a h:co ratio of ~0.7 compared to the ideal ratio of ~2. this ratio is adjusted via the water-gas shift reaction. coal-based fischer–tropsch plants produce varying amounts of co, depending upon the energy source of the gasification process. however, most coal-based plants rely on the feed coal to supply all the energy requirements of the fischer–tropsch process.
fischer–tropsch process