Structure of Genes

Question 1

PROMOTER:

Where is the promoter region and what is the purpose of it?

Where? What? How?

Answer 1

The region is an upstream (5’ end) binding site for RNA polymerase (the enzyme responsible for transcription)
* denotes the starting position and direction of transcription
* RNA polymerase binds to the promoter region of a gene, allowing for transcription of that particular gene

Question 2

Where is the operator region and what is the purpose of it?

+ mention which kind of organisms contain the operator region

Answer 2

The region that serves as a binding site for repressor proteins, that can inhibit gene expression
* Only found in prokaryotic genes

eukaryotes have different regions for regulating gene expression

Question 3

Where is the leader region and what is the purpose of it?

Answer 3

• upstream of coding
• downstream of operator and promoter
  important role in gene regulation

Question 4

Where is the termination sequence and what does it do?

What are the 3 STOP codons?

Answer 4

• Located at the end of the gene
• Represents a sequence of DNA that signals for the end of transcription
• Controlled by STOP codons
  (UAA, UAG, or UGA)

Question 4

What is the difference between introns and exons?

Answer 4

INTRONS
regions of non-coding DNA that do not contribute to the final protein as they are removed during RNA processing
* (only in eukaryotic cells)

HOWEVER,

EXONS
regions of coding DNA that are transcribed and translated into the final protein
* (in both eukaryotes and prokaryotes