Transcription and RNA processing

DNA, RNA, proteins

genetic info flows from ? to ? to ?

Ribosome function

contain RNA and assemble proteins

mRNA

molecule created from DNA during transcription

• carries genetic info from DNA to ribosomes using codons

non-template strand

gene targeted for transcription

• also called the “coding strand”

RNA polymerase

enzyme that adds RNA nucleotides to make mRNA

tRNA

transfer RNA that helps create specific polypeptide sequences by directly pairing up with mRNA 3-base sequences

• reads mRNA with anticodons

rRNA

functional units of ribosomes that are responsible for protein assembly

codon

3-base sequence on mRNA that pairs with anticodon

anticodon

3-base sequence on tRNA that pairs with codon

poly-A tail

modification to made to mRNA after transcription

• increases stability

• helps exportation from nucleus

3’ end

what end is the poly-A tail added to

GTP cap

modification made to mRNA after transcription

• protects transcript

• helps ribosomes attach to mRNA

5’ end

what end is the GTP cap added to

introns

sequences of mRNA that don’t code for amino acids

• excised during RNA processing / thrown out before RNA transcript matures

exons

sequences of mRNA that are expressed in coding for amino acids

primary mRNA

initial mRNA transcript that has both intron and exons

Alternative splicing

single gene can produce multiple, different proteins by selectively including or excluding certain exons from the mature mRNA