DNA transcription

the process by which a sequence of DNA nucleotides is used as a template for the synthesis of an RNA molecule

what is transcription?

messenger RNA
transfer RNA
ribosomal RNA
noncoding RNA

what are the major RNA molecules?

to encode the amino sequences of polypeptides

what is the function of mRNA?

read the mRNA and transfer the appropriate amino acid to the polypeptide chain

function of tRNA

forms ribosomes which read mRNA to make proteins

what does rRNA do?

everything

how much of the chromosome is transcribed?

catalytic, structural, regulatory

what are the functions of non-coding RNA

the sum of all the RNA molecules produced in a cell

what is a transcriptome?

RNA polymerases

RNA is synthesized by ____

DNA template

RNA synthesis requires a _____

no

does RNA polymerase require a primer

5'-3'

which direction is RNA built in

3'-5'

the DNA template is copied in which direction?

3'-5'

what type of exonuclease proofreading activity does RNA polymerase NOT have

1

which, 1 or 2, is the coding strand?

the complementary strand that is identical to the new RNA

what is the coding strand?

2

which is the template strand (1 or 2)?

it serves as the template for RNA synthesis

what is the purpose of the template strand?

RNA polymerase, DNA, and transcript (mRNA)

what does the transcription bubble contain?

the sequence of DNA needed for the RNA polymerase to recognize the starting point

what is a promoter?

the sequence of the promoter that is common in most DNA and is recognized by the RNA polymerase

what is a consensus sequence?

-10 TATAAT
-35 TTGACA

promoters of prokaryotes

-30 TATAA
+1 Inr

promoters of eukaryotes

initiation
elongation
termination

what are the three transcription stages?

- RNA polymerase recognises and binds to recognition sites of promoter region
- closed complex --> open complex

what happens in initiation

- transcription bubble
- mRNA transcribed

what happens at elongation

- termination sequence in template RNA signals RNA polymerase to end mRNA sequence
- mRNa base pairs with itself forming a loop

Rho independent termination

- termination sequence in template RNA signals RNA polymerase to end mRNA sequence
- Rho binds to specific mRNA sequence
- mRNa does not loop around itself

Rho dependent termination

eukaryotic

which, prokaryotic or eukaryotic transcription is more complex?

eukaryotic

which, prokaryotic or eukaryotic transcription has several RNA polymerases?

- necessary for initiation
- recognise specific sites on promoters

transcription factors

pre-mRNA --> mature mRNA

RNA maturation

prokaryotes

mRNA maturation does not occur in ...

5' cap is added
3' poly tail is added
introns are spliced

what occurs during mRNA processing?

eukaryotes

mRNA maturation only occurs in....

protects mRNA from enzymatic destruction

what does the 3' poly tail do?

to protect mRNA from ribonucleases and bind mRNA to ribosome

the function of the 5' cap is....

exon

which, exon or intron, is the coding segment?

both

which, introns or exons, are transcribed by RNA polymerase?

exons

a mature mRNA is only made up of ...

a specific exon may or may not be included into the mature mRNA
allows us to get more than 1 protein from the same gene depending on exons

what does alternative processing mean?

when a gene can give rise to multiple different proteins

what is differential mRNA processing

DNA ligase

after splicing how are exons stuck back together