BIO1022 Lecture Notes - Lecture 2: Chromosome, Intron, Base Pair
Lecture 2 (28/7): Molecular Biology
DNA: transcription, translation and mutation
· DNA is read in 3’s: AUG AAG
· Codon table: What the 3 bases codes
· Watson and Crick designed the DNA double helix
Translation initiation
· Occurs by the assembly of the ribosomal subunits and initiator tRNA (pre-tRNA) at the start codon on the
mRNA.
Translation termination
· Occurs when a ribosome reaches the codon UAG, UAA or UGA on an mRNA strand than protein synthesis
is terminated
Polymorphism
· A discontinuous genetic variation
· Results in the occurrence of several different forms or types of individuals
· Individuals are among the members of a single species
· Eg; skin colour, height
Mutation
· Occurs when a DNA gene is damaged or changed
· The genetic message carried by that gene is altered
· Eg; Dwarfism
What causes mutations
· Oxidate damage from normal cellular metabolism
· Errors in the process of DNA replication or DNA recombination
o An improper/incorrect base has been put in place
o Still failure rates
· Chemicals
o Eg; chemical mutagens and chemicals in tobacco
· Radiation
Document Summary
Dna is read in 3"s: aug aag. Codon table: what the 3 bases codes. Watson and crick designed the dna double helix. Occurs by the assembly of the ribosomal subunits and initiator trna (pre-trna) at the start codon on the mrna. Occurs when a ribosome reaches the codon uag, uaa or uga on an mrna strand than protein synthesis is terminated. Results in the occurrence of several different forms or types of individuals. Individuals are among the members of a single species. Occurs when a dna gene is damaged or changed. The genetic message carried by that gene is altered. Errors in the process of dna replication or dna recombination: an improper/incorrect base has been put in place, still failure rates. Chemicals: eg; chemical mutagens and chemicals in tobacco. Radiation: eg; uv, x-ray and gamma. Different cell types in the human body have developed from a single sperm and egg. However, they have many differences in their structure and function.