Question

Do all cells have the same promoters?

Answer 1

I just Googled your question, but this is what I understood. A promoter is a strand of DNA that initiates transcription of a particular gene. Promoters can be 100-1000 base pairs long, thus resulting in many many different results. So, to answer your question, all cells don't have to have the same promoters.

Answer 2

The answer is don't, because in the cell nucleus, the promoters are distributed preferentially at the chromosomal territories, likely for the co-expression of genes on different chromosomes. In humans, promoters show structural features for each chromosome.

Answer 3

Yes, they do. A promotor is part of a DNA strand - one portion of the AACCTTGG sequence - and all cells in a body have all the same DNA.

Now, different cells modify the activity of different promoters in different ways. For example, if in a particular tissue or in a particular cell in response to a particular biochemical condition (such as oxidative stress), a particular gene should not be transcribed - the promotor DNA sequence will be chemically modified (i.e., methylated) so that the proteins that bind the promotor can't reach it, and the gene won't be transcribed.