Gene Structure & Expression

5’ UTR

A space for ribosome to bind to

Similar to the way the RNA polymerase knows where to start with the promoter

3’ UTR

regulates mRNA post transcription

Gene Structure Left to Right

Promoter & RNA pol — 5’ UTR Exon — Intron —- 3’ UTR

Prokaryote Gene Structure

• Each gene has its own 3’ and 5’ UTR

• Ribosomes bind to 3’ UTR to produce proteins

• No gene splicing

• exons and introns

Bioinformatics Gene Bank: If it’s before first exon

Promoter

Bioinformatics Gene Bank: If it’s between exons

It’s an intron

Bioinformatics Gene Bank: If it’s at the start of CDS

It’s a UTR 5’

Bioinformatics Gene Bank: If it’s at the end of CDS

It’s UTR 3’

The spliceosome is a complex that removes introns from pre-mRNA to form mature mRNA. Spliceosome recognizes specific sequence within the intron. Check the intron sequences from GenBank record NG_029054.1, you will notice that introns often start with ____, and end with ___.

starts with ag, ends with gt

 After an RNA molecule is transcribed from a eukaryotic gene, what is removed and what is spliced together to produce an mRNA molecule with a continuous coding sequence?

introns are removed and exons are spliced together

Define a gene

DNA sequences that encode for a polypeptide or mRNA molecule

Where does RNA polymerase begin transcribing a gene into mRNA? And what’s the purpose of the RNA polymerase

RNA polymerase begins transcribing at the promoter. It’s purpose is to unwind the RNA and add nucleotides to the growing strand of RNA

DNA template strand	5'_____________3'
DNA coding strand	3'_____________5'

Given the locally unwound double strand of DNA in the figure above, in which direction and on what strand does the RNA polymerase move during transcription?

3'→5' along the complementary strand

5'→3' along the template strand

3'→5' along the template strand

5'→3' along the complementary strand

During transcription, RNA polymerase slides along the template strand 3’ to 5’ to synthesize RNA 5’ to 3’

DNA template strand	5'_____________3'
DNA coding strand	3'_____________5'

During transcription of the DNA in the figure above, where would the promoter be located?

to the left of the template stand

to the right of the coding strand

at the 3' end of the newly made RNA

to the right of the template strand

The promoter would be located on the left of the template strand on the 5’ end because RNA polymerase moves 5’ to 3’ and the promoter is at the beginning

Which side, 3’ or 5’ , is upstream and downstream

5’ is upstream and 3’ is downstream

which chromosome arm, p or q, is long?

q is the long chromosome arm

which chromosome arm, p or q, is short?

p is the short chromosome arm

What is the TATA box ?

the TATA box is found in the promoter region of archaea and eukaryotes. It helps initiate transcription b acting as a binding site for the transcription factors?

part of the promoter, called the TATA box, is said to be highly conserved in many different organisms through evolution. Why this is the case?

Any mutation in the sequence is selected against

In which direction does RNA polymerase move along the DNA?

5’ to 3’ on the template strand