Differences in translation and transcription in prokaryotes and eukaryotes? Differences in translation and transcription in prokaryotes and eukaryotes? Solution Transcription is the generation of RNA molecules from DNA and Translation is the generation of protein molecules from RNA. In this way the information from DNA is passed for synthesis of new proteins or enzymes. Although the basic concepts of transcription and translation are same into prokaryotes and eukaryotes but due to organizational differences between the two cell types some differences are there in their transcription and translation. Because in prokaryotes there are no nucleus both processes here take place in cytoplasm. But in eukaryotes RNA transcript generation and post transcriptional processing occurs in nucleus. Apart from that following differences are present in transcription for the two cell types. In transcription RNA polymerase is responsible for reading the codes of DNA. Three types of RNA molecules are there: rRNA for ribosomal RNA, mRNA or messenger RNA for all RNA except ribosomal and tRNA and tRNA or transfer RNA required during translation or transfer of information from RNA to protein. In prokaryotes all the three types of RNA are produced by single type of RNA polymerase and the polymerase is composed of five polypeptides. In eukaryotes there are three types of polymerases namely rRNA is transcriped by RNA Pol I, mRNA by Pol II and tRNA by Pol III. Each type is composed of 10-15 polypeptides. Transcription has three phases: Initiation, elongation and termination. Seperate enzymes and protein factors are required during each phase. In prokaryotes no initiation factors are there & number of elongation factors are much less than prokaryotes. In eukaryotes initiation factors are TFIIA, TFIIB, TFIID, TFIIE, TFIIF and TFIIH. Another major difference is the polycistronic nature of mRNA in prokaryotes i.e genes more than one present on a single mRNA transcript. But eukaryotic mRNA is monocistronic i.e each mRNA contains a single gene. In prokaryotes termination is of 2 types rho factor dependent and rho factor independent. But in eukaryotes transcripts are vary long and actual process is still unknown. After generation of primary transcript the post transcriptional processing of the RNAs are less complex in prokaryotes in comparison to eukaryotes. In prokaryotes translation begins immediately following transcription. But in eukaryotes all the three types of RNAs undergo many post transcriptional modifications where the unnecessary sequences are cut off and some sequences are also added up. For example 5\' capping, addition of the poly A tail, and splicing. The 5\' capping reaction replaces the triphosphate group at the 5\' end of the RNA chain with a special nucleotide that is referred to as the 5\' cap. It is thought to help with mRNA recognition by the ribosome during translation. A modification also takes place at the opposite end of the RNA transcript. To the 3\.

1. Differences in translation and transcription in prokaryotes and eukaryotes?
Differences in translation and transcription in prokaryotes and eukaryotes?
Solution
Transcription is the generation of RNA molecules from DNA and Translation is the generation
of protein molecules from RNA. In this way the information from DNA is passed for synthesis
of new proteins or enzymes. Although the basic concepts of transcription and translation are
same into prokaryotes and eukaryotes but due to organizational differences between the two cell
types some differences are there in their transcription and translation.
Because in prokaryotes there are no nucleus both processes here take place in cytoplasm. But in
eukaryotes RNA transcript generation and post transcriptional processing occurs in nucleus.
Apart from that following differences are present in transcription for the two cell types.
In transcription RNA polymerase is responsible for reading the codes of DNA. Three types of
RNA molecules are there: rRNA for ribosomal RNA, mRNA or messenger RNA for all RNA
except ribosomal and tRNA and tRNA or transfer RNA required during translation or transfer of
information from RNA to protein. In prokaryotes all the three types of RNA are produced by
single type of RNA polymerase and the polymerase is composed of five polypeptides. In
eukaryotes there are three types of polymerases namely rRNA is transcriped by RNA Pol I,
mRNA by Pol II and tRNA by Pol III. Each type is composed of 10-15 polypeptides.
Transcription has three phases: Initiation, elongation and termination. Seperate enzymes and
protein factors are required during each phase. In prokaryotes no initiation factors are there &
number of elongation factors are much less than prokaryotes. In eukaryotes initiation factors are
TFIIA, TFIIB, TFIID, TFIIE, TFIIF and TFIIH.
Another major difference is the polycistronic nature of mRNA in prokaryotes i.e genes more
than one present on a single mRNA transcript. But eukaryotic mRNA is monocistronic i.e each
mRNA contains a single gene.
In prokaryotes termination is of 2 types rho factor dependent and rho factor independent. But in
eukaryotes transcripts are vary long and actual process is still unknown.
After generation of primary transcript the post transcriptional processing of the RNAs are less
complex in prokaryotes in comparison to eukaryotes. In prokaryotes translation begins
immediately following transcription. But in eukaryotes all the three types of RNAs undergo
many post transcriptional modifications where the unnecessary sequences are cut off and some
sequences are also added up. For example 5' capping, addition of the poly A tail, and splicing.

2. The 5' capping reaction replaces the triphosphate group at the 5' end of the RNA chain with a
special nucleotide that is referred to as the 5' cap. It is thought to help with mRNA recognition
by the ribosome during translation. A modification also takes place at the opposite end of the
RNA transcript. To the 3' end of the RNA chain 30-500 adenines are added in what is called a
poly A tail. As genes in eukaryotes are interrupted by non coding regions called introns splicing
is must where the introns are cut off and the exons are joined. After all these modifications the
mature RNAs are released from nucleus to cytoplasm where translation would take place.
In prokaryotes all the different types of ribosomal RNAs i.e 16s, 5s and 23 s are generated from a
single primary transcript. But in eukaryotes all the different units of 28s, 18 s, 5.8 s and 5s are
produced from 2 transcripts.
Like transcription traslation has three phases: initiation, elongation and termination and takes
place in ribosome. In initiation phase the 30s ribosome binds to a particular Shine Dalgarno
sequence of mRNA.The ribosome has three active sites: the A site, the P site, and the E site. The
A site is the point of entry for the aminoacyl tRNA (except for the first aminoacyl tRNA, which
enters at the P site). The P site is where the peptidyl tRNA is formed in the ribosome. And the E
site which is the exit site of the now uncharged tRNA after it gives its amino acid to the growing
peptide chain.The initiation complex forms keeping the initiation codon AUG at the P-site. In
prokaryotes only three initiation factors are required namely IFI, IFII, and IFIII. But in
eukaryotes 7 initiation factors are required ((eIF1, eIF2, eIF3, eIF4, eIF5A, eIF5B, eIF6).
During elongation the first amino acid that comes is fMet in prokaryotes and methionine in
eukaryotes (in prokaryotes the methionine is formylated to give the first amino acid methionine a
seperate identity from others). So first tRNA that comes is also Met-tRNA-fMet
Elongation of the polypeptide chain involves addition of amino acids to the carboxyl end of the
growing chain. The growing protein exits the ribosome through the polypeptide exit tunnel in the
large subunit. Two types of elongation factors are required (EF-Tu and EF-Ts) in prokaryotes
and in eukaryotes these are eEF1 and eEF2. Speed of translation is 20 amino acids per second in
prokaryotes whereas in eukaryotes it is 1amino acid per second. The mRNA is short lived few
seconds to few minutes in prokaryotes and it is few hours in eukaryotes.
In prokaryotes termination is facilated by 3 termination factors (RF1, RF2, RF3) whereas in
eukaryotes only one the release factor is there (eRF1).
Post translation modification of proteins takes place in cytoplasm in prokaryotes. In eukaryotes
the complex process of post translational processing takes place in endoplasamic reticulum or
golgi apparatus.