Translation (protein synthesis)RNA >Protein

1. Tittle
Translation
BS 4th semester presentation
By
Sikandar Ali
Department Of Microbiology UOB,
Quetta Pakistan
WhatsApp number: +923368179410
Gmail: sikanderalisumalani11@gmail.com

2. Translation (protein synthesis)
RNA >Protein
 Replication is carried by DNA
polymerase
 Transcription is carried out by RNA
polymerase
 Translation performed on
Ribosomes

3. Translation
Translation refers to the process of creating protein from mRNA
template.
The sequence of nucleotides on the RNA is translated into the amino
acid sequence.
The protein and this reaction is carried out by ribosomes.
Multiple enzymes in an energy intensive process the uses ATP as well
as GTP

4. RNA’s
RNA (ribonucleic acid) that functions in
cellular protein synthesis.
RNA carrier of genetic codes in
some viruses.
The three main types those function
Synthesis protein.
• mRNA, rRNA & tRNA

5. mRNA
mRNA transcribes the genetic
code from DNA into a form that can
be read and used to make proteins.
mRNA just 10 microns in diameter
mRNA carries genetic information
from the nucleus to the cytoplasm of
a cell.

6. TYPES OF mRNA
The two main types of mRNA:
Monocistronic mRNA
A monocistronic mRNA molecule contains the exon sequences coding
for a single protein.
Most eukaryotic mRNAs are monocistronic
Polycistronic mRNA
A polycistronic mRNA molecule contains the exon coding sequences for
multiple proteins.
Most mRNA of bacteria and bacteriophages (viruses that live in bacterial
hosts) are polycistronic..

7. rRNA
ribonucleic acids (RNA) are a group of large
molecules that have many different roles.
As the name, ribosomal RNA (rRNA) is part of
the ribosome.
 rRNA is located in the cytoplasm of a cell,
where ribosomes are found.

8. Ribosome
Ribosomes are approximately 60% rRNA
and 40% protein by weight.
A ribosome contains two subunits, (LSU)
and (SSU)
Prokaryotes have 70S or 50S subunits.
Eukaryotes have 80S or 60S subunits to.
A ribosomes has an mRNA binding site and
three tRNA binding site.
The tRNA binding site are APE
• A:aminocyle tRNA
• P:peptidyl tRNA
• E:exit

9. tRNA
Like rRNA, tRNA is located in the cellular
cytoplasm and is involved in protein
synthesis.
Transfer RNA brings or transfers amino
acids to the ribosome that corresponds to
each three-nucleotide codon of rRNA.
The amino acids then can be joined
together and processed to make
polypeptides and proteins.

10. Codon
A codon is a sequence of three RNA nucleotides that
corresponds with a specific amino acid or stop signal
during protein synthesis.
Each codon corresponds to a single amino acid (or stop
signal), and the full set of codons is called the genetic
code.
The codon AUG is called the START codon as it the first
codon in the transcribed mRNA that undergoes
translation.
There are 3 STOP codons in the genetic code - UAG,
UAA, and UGA.

13. Anticodon
The anticodon region of a transfer RNA is a sequence
of three bases that are complementary to a codon in
the messenger RNA.
During translation , the bases of the anticodon form
complementary base pairs with the bases of the
codon by forming the appropriate hydrogen bonds
In this diagram you see a tRNA that has the
anticodon UUU which is complementary to the codon
AAA.
The codon AAA specifies the amino acid
phenylalanine.

14. Wobble hypothesis
The Wobble hypothesis proposes that
normal base pairing can occur between
nitrogen bases in positions 1 and 2 of the
codon and the corresponding bases (3 and
2) in the anticodon.
Actually, the base 1 in anticodon can form
non-Watson-Crick base pairing with the
third position of the codon.
The hypothesis is applicable to most (not
all) tRNAs.

16. Three phases of translation
• Initiation translation
• Elongation
• Termination

17. Initiation
• A ribosome (which comes in two pieces,
large and small)
• An mRNA with instructions for the protein
we'll build
• An "initiator" tRNA carrying the first amino
acid in the protein, which is almost always
methionine (Met)
• During initiation, these pieces must come
together in just the right way. Together,
they form the initiation complex, the
molecular setup needed to start making a
new protein.

18. Elongation
• While Met-tRNA occupies the P site, another
aminoacyl-tRNA with an anticodon
complementary to the next codon comes to
occupy the A site.
• This process requires GTP. The enzyme peptidyl-
transferase forms a peptide bond between
methionine and the next aminoacyl-tRNA.
• The tRNA molecule in the P site becomes
uncharged and leaves the ribosome. The
ribosome then translocates along the mRNA
molecule to the next codon.
• This opens up the A site for the next aminoacyl-
tRNA. The polypeptide chain is built up in the
direction from the N terminal to the C terminal

19. Termination
• One of the three stop
codons enters the A site. No tRNA
molecules bind to these codons so
the peptide and tRNA in the P site
become hydrolysed releasing the
polypeptide into the cytoplasm.
• The small and large subunits of the
ribosome dissociate ready for the
next round of translation.