Translation
How is Genetic Information Translated
How is mRNA translated into a protein?
Difference between mRNA and tRNA
Description
Redundancy in the Genetic Info Processing System
To reduce the number of chance errors that could potentially occur.
Example: Lac Operon
Bacteria E-Coli uses glucose for energy needs.
-typically if lactose is present and glucose is not, lactose molecules can activate the 'lac operon'
- basically has a single promoter and three genes that produce enzymes helping convert lactose to glucose
-typically if lactose is present and glucose is not, lactose molecules can activate the 'lac operon'
- basically has a single promoter and three genes that produce enzymes helping convert lactose to glucose
Promoter/Operator
Can allow us to regulate which part of the gene gets used. Helps control transcription.
Eukaryotic mRNA
Eukaryotic mRNA- carries information copied from DNA
has a unique 3' end called the poly A tail
A methylated cap is found at the 5' end
mRNA also contains codons that wll encode for specific amino acids
-actually contains the info for the protein of interest
has a unique 3' end called the poly A tail
A methylated cap is found at the 5' end
mRNA also contains codons that wll encode for specific amino acids
-actually contains the info for the protein of interest
Ribosomal RNA
associates with a set of proteins to form ribosomes
Transfer RNA
Desciphers the code and delivers the specific amino acid
-contains anticodons
-contains anticodons
Polypeptide Chain
Description
Information Processing Steps
Starts getting read from 5' end move to the 3' end
Initiation
- Small ribosomal sub-unit binds to the tRNA with the first amino acid and binds to the mRNA
- Large ribosomal unit binds t the complex (large ribosomal unit has three binding sites, a p, and e)
- Large ribosomal unit binds t the complex (large ribosomal unit has three binding sites, a p, and e)
Elongation
Second tRNA with an amino acid enters into the ribosome and sits in the A site.
Translocation
Ribosome slides along to the next codon on mRNA, moving the (second) tRNA amino acid Met from A to P site and first tRNA to E site
Termination
STOP codon on the mRNA is reached, a release factor enters the A site the ribosome associates and translation ends.
Repeats
Ribosome Sites: A, P, E
tRNAs in the A site translocates to the P site then enter the E site before leaving the ribosome.
Translation Process
Amino Acids
Only 20 types to form all proteins.
Codons vs. Amino Acids
There are 64 possible Codons, only 20 AA, why?
- To reduce the likelihood of an error in the transcription of the mRNA
- To reduce the likelihood of an error in the transcription of the mRNA
Redundancy
Degeneracy makes a more robust system
Note
Note
Multiple codons give us the same code for the same amino acids to reduce errors in the system.
Note
Description
Cellular Function/Gene Expression
Repressor Protein bound to the promoter
When lactose is in the cell, it binds to the repressor and changes the shape of the protein causing it to fall off of the DNA. The transcription factors and polymerase now can transcribe the section of genes.