What are the difference between an operator and a promoter?

Question

Accepted Answer

Operators and promoters are vital DNA sequences that are involved in the transcription process. These are the key differences between an operator and a promoter:

Basis for comparison

Operator
Promoter

Definition
A specific section of DNA where transcription factors bind, inhibiting transcription
A specific sequence of DNA where transcription begins

Presence
Found only in prokaryotes
Found in prokaryotes and eukaryotes

Function
Regulate gene expression by binding the repressor and inhibiting transcription of downstream genes 
Controls gene expression by signaling the RNA polymerase to begin transcription and in which direction the polymerase should transcribe the DNA

Basis for comparison	Operator	Promoter
Definition	A specific section of DNA where transcription factors bind, inhibiting transcription	A specific sequence of DNA where transcription begins
Presence	Found only in prokaryotes	Found in prokaryotes and eukaryotes
Function	Regulate gene expression by binding the repressor and inhibiting transcription of downstream genes	Controls gene expression by signaling the RNA polymerase to begin transcription and in which direction the polymerase should transcribe the DNA

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