Lecture 1B: Ribosome Flashcards
Intact, complex, and complete which consists of the large subunit and the small subunit.
Ribosome
Sedimentation coefficient in centrifugal force in prokaryotes
70s
Formulated the unit precipitation of sedimentation coefficient.
Svedberg
large subunit sedimentation coefficient
50s
small subunit sedimentation coefficient
30s
Ribosome is functional only in ____ _____.
70s form
How important is the function of the ribosome?
- proteins which are the products of the process of translation–serve very important role in the cell.
- Some proteins have structural role
Also have a 30s and 50s ribosomal subunits that yields also 70s type ribosomes.
Archaea
Ribosome is a very highly dynamic structure. It can __________ and _________.
assemble and disassemble
Ribosome cannot participate in translation if the subunits are not complex. Why?
because it is only upon the complex formation of the three important sites of ribosome (E, P, A site) that participates in the translation process are honed.
In the large subunit, there is that binding site for what we call _____
tRNA
In Bacteria, the most always first amino acid in the mRNA transcript.
Methionine (Met)
a complimentary sequence codon for the first amino acid Met
anticodon sequence on the tRNA (UAC).
What happens when tRNA is attached to a specific amino acid?
tRNA will be activated
What does it mean when the tRNA is activated?
That means that it is ready to participate in the elongation or polymerization of the proteins
How to read the mRNA sequence?
From 5’ to 3’
What is activated ribosome?
the attachment of both small and large subunit in participation of energy such as ATP and GTP
Where does the transcript attaches?
small subunit
- It is called the exit site, which holds the de-acetylated tRNA
E site
What does de-acetylated tRNA mean?
When the bound amino acid is released from tRNA to form a peptide bond to the previous amino acid
What is P site?
Peptidyl site which accommodates tRNA molecule carrying the peptide chain
What is A site?
Aminoacyl site which accepts amino acetylated tRNA molecules bearing amino acid ready for incorporation to the growing polypeptide chain.
In the Ribosome, which subunit does the initiation of protein synthesis or the start of translation always begins
in the small subunit
How does ribosome know what tRNA it accommodates?
Remember there is a codon on the mRNA that guides the sequence of the amino acid, so only the anticodon that can form a complimentary interaction with that codon will be able to get in.
It will not fit to the ribosome if?
it is the wrong tRNA
very critical to the accuracy of protein synthesis
Translocation. The transfer from one side to another.
The ribosome must move exactly one codon at each step or else the _______ of each process could be compromise.
Fidelity
several ribosomes can actually translate a single mRNA molecule simultaneously. In other words, many ribosomes are attached to a single mRNA.
Polysomes
Polysomes increase both of the _____ and _______ of translation because each ribosome can make a complete polypeptide.
speed and efficiency
What happens when the ribosomes reaches a stop codon?
Translation terminates
There is not stop codon, instead, they have these protein called ______ _______.
Release factors
- They recognize stop codon.
- They cleaved the attached polypeptide from the final tRNA releasing the final finish product.
Release factors
What happens to the ribosome when the translation terminates?
It will dissociate
Note: Not all the time proteins are _________.
Synthesizing
