1.5 The strucure of genes

What is the coding region?

A part of the gene that contains the coded information for making a polypeptide chain

What are the flanking regions?

Regions located either downstream or upstream of a region of a gene

What are promoter regions?

Regions located at the beginning of a gene which are rich in A,T nitrogenous bases and CAAT which makes transcription process more efficient

What occurs at the promoter region?

Where transcription factors and RNA polymerase bind to initiate transcription

What is a leader region?

Contains sections known as attenuators that are involved in gene regulation

What are operator regions?

In between the promoter and the gene being transcribed is a binding site for repressor proteins (proteins which prevent transcription) to continue the process of transcription only present in prokaryotic cells

What is the differences between eukaryotic and prokaryotic gene structures?

In prokaryotic genes there are operator regions however in eukaryotic gene structures there are no operator regions and instead have enhancer regions which can turn on or off the expression of a gene

What is a repressor?

Proteins which prevent transcription

What is a Tata box?

A sequence of the promoter region, which is where the RNA polymerase binds

What is the CAAT box ?

A region which makes the process of transcription more efficient

What are UTR‘s (untranslated regions) ?

The UTR’s tell the guanine cap and the poly a tail where to bind

What is the general sequence of regions in a eukaryotic structural gene?

enhancer + silencer —— promoter region with the tata box, the 5’ UTR, the start codon, exons and introns, stop codon, 3’ UTR —— terminator

What is the general sequence of regions in a prokaryotic structural gene?

enhancer/repressor —— Promoter region, operator region, 5’ UTR (leader), start codon, coding sequence, stop codon, 3’ UTR(trailer), terminator.

What are enhancers and silencers?

short, specialized DNA sequences acting as molecular switches to control gene expression by increasing (enhancers) or decreasing (silencers) transcription rates

What is a genetic code?

The instructions used by cells to translate information encoded within genetic material into proteins