D1.2 Protein synthesis HL Flashcards
post-transcriptional modification in eukaryotes
primary mRNA transcript produced by transcription is altered to become mature mRNA, which includes adding a 5’ cap, a poly-A tail, and splicing out introns
purpose of adding a 5’ cap and poly-A tail to mRNA
protect mRNA from degradation and assist in its export from the nucleus and attachment to ribosomes
introns and exons in the context of mRNA splicing
Introns are non-coding sequences removed during mRNA processing, exons are coding sequences that are joined together to form the final mRNA
alternative splicing
process where a single gene creates multiple proteins by combining different exons in various ways, leading to the production of different mRNA molecules from the same DNA sequence
How does alternative splicing contribute to protein diversity?
By producing different mRNA variants from the same gene, it leads to the creation of multiple, functionally distinct protein isoforms, increasing the diversity of proteins in an organism
Directionality of Transcription and Translation
in cells it occurs in the 5′ to 3′ direction. This directionality is crucial for the correct assembly of mRNA in transcription and amino acids in translation
Role of the Promoter in Transcription
The promoter is a DNA sequence where transcription factors bind, initiating transcription. Its interaction with transcription factors is vital for RNA polymerase to start transcribing DNA into RNA
Non-Coding DNA Regions
It does not encode proteins but plays essential roles in regulating gene expression, maintaining chromosome integrity, and other vital cellular processes
RNA Polymerase in Transcription
catalyzes the formation of mRNA from DNA. It binds to the promoter region only when specific transcription factors are present, initiating transcription
mRNA Orientation in Translation
During translation, mRNA moves through the ribosome in a 5′ to 3′ direction. This correct orientation is crucial for accurate amino acid sequence assembly in the resulting polypeptide
Initiation of Translation
Translation begins when mRNA binds to a small ribosomal subunit. The start codon AUG, linked to the initiator tRNA carrying methionine, initiates this process
Role of AUG Codon
AUG is the start codon in mRNA that signals the beginning of translation, binding with the initiator tRNA carrying methionine
Pre-proinsulin to Insulin Conversion
synthesized during translation, is converted into insulin through post-translational modifications including the removal of the signal peptide and C-peptide, and the formation of disulfide bridges
Function of Proteasomes
recycle amino acids by breaking down unneeded or damaged proteins, maintaining a healthy proteome and amino acid supply
Translation Complex Assembly
It is assembled when the mRNA’s 5′ end binds to the small ribosomal subunit, followed by the initiator tRNA and large ribosomal subunit, allowing translation to commence
