Rna Synthesis

DNA Transcription

1.

a. The initiation complex contains messenger RNA, transfer RNA, and ribosomes. The process begins with the start codon AUG. The codons of mRNA pair with corresponding tRNA anti codons through hydrogen bonding. Transfer RNA carries amino acid specific to the anticodon, where every three nucleotides code for one tRNA. The ribosome structure includes two subunits. They join codons with corresponding anticodons, and amino acids. A continuous chain results because tRNA leaves behind amino acid. The stop codon does code for amino acids and instead terminates the process. Ribosomes and mRNA are disengaged by release factors then recycled.

b. Chaperonin proteins fold amino acid sequence into shape. The protein in then injected into ER lumen by ribosome. Vesicles that contain insulin are secreted from the ER to the golgi apparatus, where insulin

a. An operon is a set of genes with all regulatory mechanisms. The operator binds the repressor, while the promoter binds RNA polymerase, which creates the RNA strand. When the repressor binds to the operator, the operon, or set of genes that code for protein, is turned off. The terminator ends transcription. There are repressible operons, such as the trp operon, in which the repressor is normally inactive and the operon on. This leads to the production of a corepressor, which eventually binds to the repressor and activates it. Inducible operons, like the lac operon, are normally off with active repressors. However in the presence of lactose, the inducer allolactose binds to the repressor, making it inactive and turning the operon on. This leads to the transcription of the genes that code for proteins β-galactosidase, permease, and transacetylase.

b. Four mechanisms of eukaryotic gene regulation are the 5’ cap, which prevents degradation, the poly A tail, which allows exiting from the nucleus, the alternate splicing of introns by spliceosomes, and acetylation of histones, which makes DNA less condensed.