2. Translation is basilly the process of protein synthesis
Is the biological process by which messenger RNA is traslated into
proteins in eukaryotes.
Protein synthesized from the information contained in a molecule
of messenger RNA (mRna)
and in eukaryotes the translation occur in cytoplasm.
Proteins are composed of amino acid –there are 20 different
amino acids
In Eukaryotes,the trascription and translation are carried out in
separate compartments of the cell(the nucleus and cytoplasm)
Eukaryotic mRna precursors must be processed in the
nucleus(eg:capping)
And before they are exported to the cytoplasm for the
translation
3. Protein synthesis is accomplished through a
process called translation.
After DNA is transcribed into a messenger
RNA (m RNA) molecule during
transcription,the m RNA must be translated
to produce a protein .
In translation,m RNA along with transfer RNA
(t RNA) and ribosomes work together to
produce proteins.
4. PROTEINS ARE MANUFACTURED BY THE
RIBOSOMES .
TRANSLATION OCCUR IN THE CYTOPLASM
WHERE THE RIBOSOMES ARE LOCATED
.RIBOSOMES ARE MADE OF A SMALL AND
LARGE SUBUNIT WHICH SURROUNDS the m
RNA .IN EUKARYOTIC TRANSLATION 80S
RIBOSOMES WITH 40S AND 60S SUBUNITS
ARE USED .THE m RNA IS SYNTHESIZED
FROM DNA ONLY.
A site- aminoacyl t RNA
binding site
P site-peptidyl binding site
Esite-exit site
5. An M rna sequence template to guide the
synthesis of a chain of amino acids that form a
protein.
The translation process requires m RNA ,r RNA ,20
AMINO ACIDS and their specific t RNA.
And In the process of translation two types of
codons
1)start codons
2) end codons
The codon AUG( methionine) . Initiate the process
of translation, and one of three stop codons ie.,UAA
,UAG, or UGA.
m RNA CARRYING THE DNA INSTRUCTIONS
AND t RNA CARRYING AMINO ACIDS MEET IN THE
RIBOSOMES
AMINOACID ARE JOINED TOGETHER TO MAKE A
PROTEIN.
6. A SERIES OF THREE ADJACENT BASES
IN AN m RNA MOLECULE CODES FOR A
SPECIFIC AMINO ACID CALLED A CODON.
A TRIPLET OF NUCLEOTIDES IN t RNA
THAT IS COMPLEMENTARY TO THE
CODON IN m RNA CALLED AN
ANTICODON.
7. AMINOACYL-T RNA synthetase, also called t RNA- ligase,is an enzyme that
attaches the appropriate amino acid onto it s t RNA. So to form an aminoacyl-t
RNA.
8.
9. The mechanism of translation in eukaryotes
is similar to that of prokaryotes in several
aspects.
i. Intiation,
ii. Elongation and
iii. Termination.
10.
11. WE HAVE THE 40S SUB UNIT WITH THAT e IF3 COMES AND BIND TO THE
Esite . BUT THE Psite SHOULD BE FREE BECAUSE THE FIRST t RNA SHOULD
BE PLACED IN THE Psite NOT IN OTHER site. AND THE INITIATION FACTOR
1 & 2 BLOCK THE Asite.
THE Psite INTERACT TO THE FIRST t RNA THAT IS CARRYING THE (F
MET)FORMAILATED METHIONINE
A TERNARY COMPLEX CONTAINING F MET t rna & THE Eif2 BOUND TO
GTP ATTACHES TO THE Psite TO FORM 43S PREINITIATION COMPLEX.
12. NOW IN Psite THE t RNA NOT PROPERLY PLACED BECAUSE THERE IS NO m- RNA SO THIS IS
THE FIRST STAGE OF INTIATION EUKARYOTIC TRANSLATION.AFTER THAT
THE SECOND STAGE IS ATTACHMENT OF m RNA.SO AT THE 3’PRIME END HAVING THE POLY
ADENYLTAIL AND THE 5’PRIME HAVE THE CAPPING OF METHYLATED GUANINE
FOR THE BINDING OF m RNA TO THIS 43S RIBOSOMAL INITIATION FORM. WE REQUIR THE
OTHER ENZYMES FOR EXAMPLE e IFE,e IF4G,and F AND B WE CALL IT US e IF4F COMPLEX.
SO THIS COMPLEX WILL TO THIS m RNA .SO THE ATTACHMENT WILL TAKE PLACE
13. THIRD STAGE IS SCANNING THE START CODON BUT STILL THE t RNA NOT PROPERLY PLACED
WHAT WILL HAPPEN NOW ,THEY NEED TO FIND EXACTLY WHICH IS THE START CODON
ONCE DESIGNATED THE START CODON THEN ONLY THIS FMET t RNA WILL PLACED PROPERLY BY THE
HELP OF HYDROGEN BONDING . SCANNING IS NOTHING BUT THIS POLYADENYLTALE START MOVING
FROM THIS TOWARD THE 5 PRIME TO 3 PRIME DIRECTION. THE e LF2 BRING THAT FIRST T-RNA SO IT
WILL HYDROLYS THE GTP PLACE THE T-RNA PROPERLY AND IT WILL RELEASE THE PLACE.
14. They have assemble every thing and properly positioned the T-RNA now the stages is to bind the 60s
ribosome subunit.
The 60s subunit comes along with e iF5B intiation factor
Once the 60s subunit assembled with the 40s complex and the m-rna with the t-rna attach to it all other
factors are release like e IF3 & e IF1 as well as initiation factor 5 release because the GTP will hydrolyse
for energy required to bring the large subunit finally the 80s intiation complex is formed .
SO INITIATION (BEGINNING) in this stage ,the ribosome get together with the m-rna & the first t-rna so
translation can begin.
15. Is the middle stage,amino acids are brought
to the ribosomes by t-rnas and linked
together to form a chain.
Ribosome elongate the polypeptide chain by
the sequential addition of amino acids.
Elongation ,a cycle process involving certain
elongation factor(Efs).elongation may be
divided into three stages.
a)Binding of aminoacylt-rna to A site.
b)Peptide bond formation
c)translocation.
16. The 80s initiation complex contains met trna
in the p-site & A-site is free.
Another aminoacyl-t RNA is placed in the A-
site .
For this requires proper codon recoginition
on the m RNA & involvement of elongation
factor 1a(EF-1a) & supply of energy by GTP.
The aminoacyl-t RNA is placed in the A-
site,EF-1a & GDP are recycled to bring
another aminoacyl-t RNA.
17. Net result of peptide bond formation is the
attachment of the growing peptide chain to
the t RNA IN THE A-SITE.
18. The ribosome moves to the next codon of the
m-RNA (towards 3’-end).
This process is called translocation,involves
the movement of growing peptide chain from
A-site to P- site.
Translocation requires EF-2 & GTP.
GTP gets hydrolyzed and supplies energy to
move m-RNA.
19.
20. One of the stop or termination signals
(UAA,UAG,UGA)terminates the growing poiypeptide.
When the ribosome encounters a stop codon,there is
no t-RNA available to bind to the A site of the
ribosome,
-instead a release factor bind to it.
In eukaryotes, a single release factor-eukaryotic
release factor 1(e RF1)-recognizes all the three stop
codons,and e RF3 stimulates the termination events.
Once release factor binds,the ribosome unit fall
apart,
-releasing the large & small subunits.
-The t-RNA carrying the polypeptide is also
released,freeing up .
Ribosome recycling occurs in eukaryotes
21.
22. 1)Translation occur in the
a.nucleus
b.cytoplasm.
c.nucleolus.
2)Which is the energy rich molecule required for initiation of translation,
a.ATP
b.GTP
C.CTP
3)Which of the following is not a necessary component of translation,
a.anticodon
b.mrna
c.ligase.
4)Amino acids are joined together into a protein chain by which of the following,
a.transfer RNA
b.DNA polymerase
c.messenger RNA.
3)Difference between prokaryotic and eukaryotic translation?
4)What are the steps in the process of eukaryotic translation?
