文档介绍：e Each of You to My Molecular Biology Class
11/11/2017
1
Molecular Biology of the Gene, 5/E --- Watson et al. (2004)
Part I: Chemistry and ics
Part II: Maintenance of the Genome
Part III: Expression of the Genome
Part IV: Regulation
Part V: Methods
11/11/2017
2
Part III: Expression of the Genome
This part concerned with one of the greatest challenges in understanding the gene-how the gene is expressed.
11/11/2017
3
Part III: Expression of the Genome
Ch 12: Mechanisms of transcription
Ch 13: RNA splicing
Ch 14: Translation
Ch 15: The ic code
DNA
RNA
protein
translation
11/11/2017
4
Chapter 14: Translation
11/11/2017
5
Translation extremely costs
In rapid growing bacterial cells, protein synthesis consumes
80% of the cell’s energy
50% of the cell’s cell’s dry weight
Why?
11/11/2017
6
The main challenge of translation
The ic information in mRNA cannot be recognized by amino acids.
The ic code has to be recognized by an adaptor molecular (translator), and this adaptor has to accurately recruit the corresponding amino acid.
11/11/2017
7
Translation machinery
mRNAs (~5% of total cellular RNA)
tRNAs (~15%)
aminoacyl-tRNA synthetases (氨酰tRNA合成酶)
ribosomes (~100 proteins and 3-4 rRNAs--~80%)
11/11/2017
8
Outline
Topics 1-4: ponents of translation machinery.
T1-mRNA; T2-tRNA; T3-Attachment of amino acids to tRNA (aminoacyl-tRNA synthetases); T4-The ribosome
Topic 5-6: Translation process.
T5-initiation; T6-elongation; T7-termination.
Topic 8: Translation-dependent regulation of mRNA and protein stability
11/11/2017
9
Topic 1: mRNA
Only a portion of each mRNA can be translated.
The protein-coding region of the mRNA consists of an ordered series of 3-nt-long units called codons that specify the order of amino acids.
11/11/2017
10