Telomere, Telomerase and End replication problem (English version)

By completing this lecture, you will be able to define :
1- Telomere
2- Telomerase
3- DNA replication
4- Nucleotide structure
5- End replication problem
6- How cancer cells have an unlimited replicative capacity
And For Apoptosis lecture
( intrinsic pathway - extrinsic pathway ) and How does it happen in normal cell ? and How does cancer cell avoid apoptosis ?
• Apoptosis (English ver...
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thanks in advance.

[@Dr.tabarek_sabah]

Thank you very much this is the clearest explanation for this topic🌷🌷

[@Jumanajum_]

Thank you may allh bless you

[@kareemmohamed4215]

Well illustrated, big thanks.

[@mohamedemam8214]

ممتاز جدا

[@JWentu]

for a newbie like me it would have been great to explain 3' and 5'

[@predatqr]

Very nice vid! One question: The polymerase needs a 3' / OH group to elongate, which it can't find in the end of the lagging strand when the primers are removed. The leading strand should also start with a primer, which will be removed later. How can it be replaced with nucleotides when there also is no 3' end?

[@OrganizedMohamedNasr]

Thanks for your comment, Enzyme called DNA Polymerase came to replace primer sequence with DNA sequence to complete the DNA replication

[@predatqr]

@@OrganizedMohamedNasr But the Polymerase needs a OH- group (3' end) to elongate, right? When the primer is removed on the leading strand, there is only a 5' end

[@OrganizedMohamedNasr]

There are two types of DNA Polymerase: DNA Polymerase 3 and DNA polymerase 1 DNA polymerase 3 is the usual DNA polymerase we talked about on the lecture that needs OH group to build the new strand on 5 to 3 direction While DNA polymerase 1 is an enzyme its function is to replace the primer sequence with DNA sequence

[@OrganizedMohamedNasr]

There is still 3 end on each nucleotide on the middle and on the 3 end direction but there is lack on the first nucleotide so there is no replacment with DNA sequence thus while each time cell divides it loses one of its DNA sequence and thus we age

[@predatqr]

@@OrganizedMohamedNasr I think you are talking about the lagging strand but I meant the strand which will be synthesized without disruption. My point is that we have on both strands a primer at the 5' end and when they are removed there is no OH group for the polymerase. This should mean that we have the end replication problem on both new strands (leading and lagging strand)