Question

Regulation of Gene Expression in Eukaryotes

In eukaryotes, the Central Dogma of Genetics can be expanded to include post-transcriptional processing and post-translational processing, thus the Dogma becomes:

Replication - Transcription Post-transcriptional Processing -Translation - Post-translational Processing - Functional Protein - Expressed Trait.

This is the flow of information from the genetic material to the actual physical, chemical or behavioral trait in an organism. Of course, some traits are controlled by multiple genes and some also have an environmental component.

At many points in this pathway, the flow of information can be controlled, sped up or slowed down, or even stopped altogether. This is the topic covered in Chapters 15 and 16: Regulating the Expression of Genes (In Eukaryotes).

Eukaryotes control expression at the level of chromatin structure (affects transcription), through additional controls of transcription timing and rate, through controlling post-transcriptional processing of mRNA, through controlling translation timing and rate, through controlling post-translational processing, through controlling the longevity and breakdown of mRNAs and proteins, and through controlling the function proteins in the cell through such processes as feedback inhibition.

QUESTIONS:

CHROMATIN STRUCTURE MODIFICATION

Which of the methods of control in the reading above would be most energy efficient? Why?

Answer 1

The control of function of protein through feed back inhibition seems to be energy effecient mechanism in central dogma of the flow of genetic information from gene level to expression.

This is the process when the protein function will be determined by metabolic needs of the cell. If the downstream products in a metabolic pathway accumulated and there is no further need of producing them, then they will inhibit the previous enzymatic steps. Hence the metabolic process proceeds only when it needed by the cell.