shankar jan
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Prokaryotes do not have capping and polyadenylation of mRNA, but Eukaryotes do have capping and polyadenylation of mRNA. That’s correct, right?

How do bacterial RNA carry instructions for production of several proteins #polycistronic mRNA?

How do eukaryotic RNA carry instructions for production of only one protein #monocistronic mRNA? And then at the same time this contradicts with the fact the you have alternative splicing in eukaryotes and not in prokaryotes so essentially, many different proteins are produced from one gene in eukaryotes. Everything contradicts each other and this confuses me.

Also, are there many types of splicing? Or is just alternate splicing?

In the diagram, (the prokaryotic part) there are three phosphates at the start and I don’t understand what purpose they have there – I mean there isn’t cappying in prokaryotic mRNA so why the three phosphates at the start of its mRNA?

Prokaryotic DNA does not have exons and introns but Eukaryotic DNA does have introns and exons – this is what I concluded from the internet. But why? Is it because there is no splicing in prokaryotes? Furthermore, in the diagram, both prokaryotic and eukaryotic DNA are shown to have coding and non-coding regions of DNA – so essentially, both prokaryotes and eukaryotes have introns (non-coding regions of DNA) and exons (coding regions of DNA). So I am back on square one where everything seems to contradict each other.
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shadowdweller
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(Original post by shankar jan)
Prokaryotes do not have capping and polyadenylation of mRNA, but Eukaryotes do have capping and polyadenylation of mRNA. That’s correct, right?

How do bacterial RNA carry instructions for production of several proteins #polycistronic mRNA?

How do eukaryotic RNA carry instructions for production of only one protein #monocistronic mRNA? And then at the same time this contradicts with the fact the you have alternative splicing in eukaryotes and not in prokaryotes so essentially, many different proteins are produced from one gene in eukaryotes. Everything contradicts each other and this confuses me.

Also, are there many types of splicing? Or is just alternate splicing?

In the diagram, (the prokaryotic part) there are three phosphates at the start and I don’t understand what purpose they have there – I mean there isn’t cappying in prokaryotic mRNA so why the three phosphates at the start of its mRNA?

Prokaryotic DNA does not have exons and introns but Eukaryotic DNA does have introns and exons – this is what I concluded from the internet. But why? Is it because there is no splicing in prokaryotes? Furthermore, in the diagram, both prokaryotic and eukaryotic DNA are shown to have coding and non-coding regions of DNA – so essentially, both prokaryotes and eukaryotes have introns (non-coding regions of DNA) and exons (coding regions of DNA). So I am back on square one where everything seems to contradict each other.
Name:  27.PNG
Views: 635
Size:  268.9 KB

Would really love to hear other thoughts and opinions on this
Hey, sorry you've not had any responses to this yet - just giving it a quick bump, so hopefully someone will be along soon

SarcAndSpark or Lemur14 might know more on this one :hat2:
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Kallisto
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(Original post by shankar jan)
Prokaryotes do not have capping and polyadenylation of mRNA, but Eukaryotes do have capping and polyadenylation of mRNA. That’s correct, right?

How do bacterial RNA carry instructions for production of several proteins #polycistronic mRNA?

(...)

Also, are there many types of splicing? Or is just alternate splicing?

In the diagram, (the prokaryotic part) there are three phosphates at the start and I don’t understand what purpose they have there – I mean there isn’t cappying in prokaryotic mRNA so why the three phosphates at the start of its mRNA?

(...)
Just to answer your most important questions:

1.) Polyadenylation is just possible in eukaryotes as far as I know, so yes.

2.) Polycistronic mRNA has start and stop codons for each protein to produce: the sections from start codon to stop codon are coding, the sections which are not between these codons are not coding. That is why the mRNA is able to exclude and include sequences for proteinsbiosynthesis.

3.) Yes, there are: in terms of splicing, it is distinguished from introns and extrons: The introns are DNA sequences which don't get coding in splicing process, while the extrons get coding and forms the mRNA.

4.) The three phosphates hold the whole mRNA strand together. They are connect with the ribose molecules which are connect with the bases in turn. If they don't exist, the mRNA would shatter into pieces.
Last edited by Kallisto; 1 year ago
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shankar jan
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(Original post by Kallisto)
Just to answer your most important questions:

1.) Polyadenylation is just possible in eukaryotes as far as I know, so yes.

2.) Polycistronic mRNA has start and stop codons for each protein to produce: the sections from start codon to stop codon are coding, the sections which are not between these codons are not coding. That is why the mRNA is able to exclude and include sequences for proteinsbiosynthesis.

3.) Yes, there are: in terms of splicing, it is distinguished from introns and extrons: The introns are DNA sequences which don't get coding in splicing process, while the extrons get coding and forms the mRNA.

4.) The three phosphates hold the whole mRNA strand together. They are connect with the ribose molecules which are connect with the bases in turn. If they don't exist, the mRNA would shatter into pieces.
Thanks so much for helping me understand some parts which I was struggling with
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