Control of transcription in prokaryotes

Question 1

How do prokaryotes respond to sudden changes in the environment

Answer 1

Prokaryotes respond to sudden changes in the environment, such as an influx of nutrients, by inducing the synthesis of the appropriate proteins to metabolize the nutrients. This process takes minutes because transcription and translation are closely linked: ribosomes begin translation near the 5’-end of a new mRNA as soon as it emerges from RNA polymerase. Also, most mRNAs are degraded soon after they have been synthesized (mins)- sometimes the 5’-end is degraded before the 3’-end has even been synthesized.

Question 2

How do eukaryotes respond to sudden changes in the environment

Answer 2

In contrast to prokaryotes, the induction of new proteins in eukaryotes frequently takes hours or days, in part because transcription takes place in the nucleus and the resulting mRNAs must be transported to the cytoplasm, where translation occurs. Also, there is no need for a rapid response because eukaryotic cells, particularly those of multicellular organisms, have a relatively stable environment.