Please enable JavaScript.
Coggle requires JavaScript to display documents.
Gene Expression at the Molecular Level - Coggle Diagram
Gene Expression at the Molecular Level
Overview
Gene function: molecular function of the protein product- organism’s trait conferred by the gene.
• Central Dogma: DNA → RNA → Protein
Processes
Transcription: DNA → RNA
Translation: RNA → Protein
Transcription
Stages
Initiation: RNA polymerase binds to the promoter.
Elongation: RNA polymerase synthesizes RNA (5’ to 3’).
Termination: RNA polymerase detaches at the terminator.
Eukaryotes vs. Prokaryotes
Eukaryotes involve RNA polymerase II and transcription factors.-
Require Intervening step: RNA processing.
RNA Processing (Eukaryotes)
1) Capping: 5’ Cap (Guanosine)-> Stabilizes RNA, helps ribosome binding.
2) Splicing: Removal of introns, joining of exons. By the spliceosome.
Poly-A Tailing (3’ end): Increases RNA stability.
Translation
Stages
• Initiation: Assembly of ribosome, mRNA, and initiator tRNA
• Elongation: Peptide chain formation.
• Termination:Stop codon leads to disassembly
Key players
mRNA: Contains codons (triplets of nucleotides
tRNA: Matches codons with amino acids via anticodon.
Ribosomes: Facilitate protein synthesis.
Genetic code
Codons: Triplets of nucleotides.
Start codon: AUG (Methionine).
Stop codons: UAA, UAG, UGA.
Ribosomes
Prokaryotes have one kind of ribosome
Eukaryotes have distinct ribosomes in different cellular compartments.
Sites for tRNA binding and polypeptide synthesis
P site – Peptidyl site
A site – Aminoacyl site
E site – Exit site
Functional RNA
tRNA: Brings amino acids.
rRNA: Ribosome component.