BIOL1130 Lecture Notes - Lecture 15: Missense Mutation, Nonsense Mutation, Transfer Rna
28 May 2018
School
Course
Professor
8.2 Universal Code/ Central Dogma
Central Dogma
• Is the process of Transcription and Translation and then polypeptide formation from a.a ;-
DNA encodes into the product RNA (products are mRNA, rRNA and tRNA), and then RNA
codes for the production of polypeptide
• Note that protein does not code for the production of another protein, RNA, or DNA, and
that the process of gene expression stops once the information has passed into a protein.
• The RNA molecule is then responsible for the assembly of amino acids to form specific
proteins.
Transcription
• RNA polymerase is bind to the promoter region of DNA so the product is not the enzyme
Transcription unit
• A transcription unit is the transcribed region of DNA, between promoter and termination
sequences, with its end product being RNA
Open reading frame
• Region of mRNA that is being read during translation
• A ORF is consisted of start codon, a series of codons and then stop codon
• Can be read in any 3 reading frames, eg ACUACUACU, ACU..CUA..UAC (yielding different a.a)
Nonsense mutation
• Results in premature stop codon, malfunctioning of proteins, incomplete, truncated,
Missense mutation
• Point mutation that a single nucleotide is changed to cause a substitution of another a.a
• Does’t cause preature stop codo
• Only 1 a.a is substituted , the rest continues
Frameshift mutation
• Incorrect a.a sequence, malfunctioning protein
• Reading of the codons is shifted, different a.a is produced
• Can alter stop codon, causing long/short
Genetic codes are similar in most living organisms
RNa traslatio, codo is read fro the 5’ ed
find more resources at oneclass.com
find more resources at oneclass.com
