Question

What is the difference in gene regulation between eukaryotic and prokaryotic cells?

Answer 1

Prokaryotes have a single circular chromosome, whereas eukaryotes have many bar-shaped chromosomes. Also, prokaryotes are single-cell organisms (there are some single-cell eukaryotes, but never multicellular prokaryotes). Because multicellular organisms have so many cells, (such as humans), their chromosomes have to contain a lot of information to provide details to the cell so it can carry out its job.

Negative Prokaryotic gene regulation usually comes in the form of feedback inhibition, with the end product of the process either interfering with an enzyme early in the production process or by directly interfering with the operator sequence, acting as a repressor.

There is also positive gene regulation found in prokaryotes. In this case, a repressor is normally attached to an operator in the nucleotide sequence. A protein or a smaller molecule will act as an activator, attaching to the repressor and de-activating it.

In eukaryotic cell DNA there are introns and exons. When a gene is needed to be expressed, the cell must remove the information in the sequence that isn't needed; ie, the introns. It is believed that the same DNA sequence can actually code for more than one gene because of the cells' ability to remove introns and keep exons. for example, the word 'strawberry' contains the code for three words: straw, berry, strawberry. by removing pieces of the word, you are left with information that provides a different set of instructions. Prokaryotes do not have introns and exons.

Eukaryotic genes have a TATA box right before, and enhancers very far upstream from the promoter sequence. When activators attach to the enhancer regions, a group of mediator proteins and some transcription factors will fall into place, allowing RNA polymerase to attach. This forms the transcription initiation complex. Without any of these elements, the gene cannot be transduced. In this way, eukaryotic genes may be regulated.