Questions about DNA Replication: RNA Primer, 3' to 5', TRNA

  • Thread starter Dual Op Amp
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In summary, the RNA primer is a short sequence that allows DNA polymerase to initiate replication. It is complementary to the parental strand and is sequenced by RNA primase. The use of RNA instead of DNA for the primer may be due to the OH group in RNA providing the necessary energy for synthesis. Additionally, DNA polymerases require a 3' OH end to work, while RNA polymerases do not.
  • #1
Dual Op Amp
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I have a question, I saw many animations of DNA replication. But there's a couple of questions I don't understand.
1. What is the difference between RNA primer and DNA?
2. When it says 3' to 5', what's that?
3. Where is TRNA made?
 
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  • #2
Dual Op Amp said:
1. What is the difference between RNA primer and DNA?

The RNA primer is there to allow the polymerase to initiate replication. The primer is a short sequence and it is complementary to the parental strand. The RNA primer is sequenced by RNA primase.

Dual Op Amp said:
2. When it says 3' to 5', what's that?

It has to do with the DNA molecule. Look at the following picture
http://www.colorado.edu/MCDB/MCDB1150/ohd/dnamolecules.JPG
You see how the each nucleotides are attached. So when the the DNA polymerase is moving along it goes from the 3' end to the 5' site.

Dual Op Amp said:
3. Where is TRNA made?

tRNA is synthesis by a RNA polymerase in the same fashion than normal gene transcription. The strucuture is a normal feature of RNA and will fold without any help. The acceptor site the added but it not well known were the this is happening.
 
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  • #3
1.) RNA primer is the thing that lays down the primers. Primers are a sequence of complementary RNA bases to which the DNA polymerase begins attaching its DNA nucleotides. This is done in both the leading and lagging strand, except the lagging strand has more primers.

2.) During RNA synthesis, the DNA strand is read in a 3' to 5' direction. 3' and 5' are two ends of the DNA strand.

3.) I'm not sure, but I think tRNA is made via RNA replication

A good site for info is www.wikipedia.org ; or you can just google this stuff.

EDIT: Sorry, I see someone has answered this already...
 
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  • #4
iansmith said:
The RNA primer is there to allow the polymerase to initiate replication. The primer is a short sequence and it is complementary to the parental strand. The RNA primer is sequenced by RNA primase.

Why RNA primer instead of DNA? does the OH in RNA molecule have something to do with this? Or what else can be determining?

Edit: maybe 3' OH end supplies the energy for synthesis?
 
  • #5
DNA polimerases cannot work without a 3' OH end, but RNA polimerase can.
 

FAQ: Questions about DNA Replication: RNA Primer, 3' to 5', TRNA

What is an RNA primer in DNA replication?

An RNA primer is a short segment of RNA that is synthesized by an enzyme called primase. It serves as a starting point for DNA synthesis during DNA replication. The RNA primer provides a free 3' OH group for DNA polymerase to attach and begin adding nucleotides to build a new DNA strand.

Why does DNA replication occur in the 3' to 5' direction?

DNA replication occurs in the 3' to 5' direction because DNA polymerase can only add new nucleotides to the 3' end of an existing strand. This is due to the structure of DNA, where the 3' end has a free hydroxyl group that can bond with the 5' phosphate group of the incoming nucleotide. This process creates a new DNA strand that is complementary to the original template strand.

What is the role of tRNA in DNA replication?

tRNA (transfer RNA) is not directly involved in DNA replication, but it plays an important role in protein synthesis. During translation, tRNA molecules bring specific amino acids to the ribosome, where they are linked together to form a polypeptide chain. This process is essential for the production of proteins, which are important for various cellular functions.

How does the 3' to 5' directionality of DNA replication affect the fidelity of DNA replication?

The 3' to 5' directionality of DNA replication allows for proofreading mechanisms to occur during DNA replication. DNA polymerase has a built-in proofreading function that checks for errors in base pairing as it adds nucleotides to the new DNA strand. If an incorrect nucleotide is added, it will be removed and replaced with the correct one, ensuring high fidelity in DNA replication.

What are the consequences of errors in DNA replication?

Errors in DNA replication, also known as mutations, can have various consequences depending on their location and severity. Some mutations can lead to changes in the amino acid sequence of a protein, potentially altering its function. Others may have no effect, while some can be harmful and cause diseases. However, the body has mechanisms in place to repair most errors in DNA replication, ensuring the integrity of the genetic code.

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