تسجيلات الدكتور إلياس في الreg

رابط فيه جميع تسجيلات د.محمد القرقوري
👇
على الميديا فاير
https://www.mediafire.com/folder/3choo9j3ee1zo/Dr.Mohamed_El-Gargouri

شيت الدكتور عبد الباري في جزئية regulation &expression

شوية فيديوات يساعدُوك في القرايا 😁

https://youtu.be/ohm-avnDYcM
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https://youtu.be/h_1QLdtF8d0
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https://youtu.be/O4SdDuBnoW4
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https://youtu.be/UXI3_tbsi0E
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https://youtu.be/O7TQm67yqIk
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https://youtu.be/oefAI2x2CQM

شوية ملخصات 😁

* chromatin =Total number of chromosomes
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* DNA is a polymer of deoxyribonucleoside monophosphates
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* The nucleotides in same strand are linked by 3__5 phosphodiester bond
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* 5 end (the end with free phosphate)
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* 3 end (the end with free hydroxyl)
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* 3 end & 5 end are not attached to other nucleotides
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* hydrophilic deoxyribose-phosphate is on outside
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* hydrophobic bases are stacked inside
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* always written in sequence from 5 to 3
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* The major & minor grooves of strands
( for the binding of regulatory proteins )
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* Actinomycine D (Anticancer drug)
(intercalating into the minor groove of DNA and block at path of helicase)
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* The base pairs are perpendicular to the axis of helix
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* chargaff Rule 👌
(adenine=thymine) & ( guanine=cytosine)
&(total amount of purines = total amount of pyrimidines )
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* The base pairs are held together by hydrogen bonds
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* Two hydrogen bonds between A&T
* three hydrogen bonds between G&C
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* The loss of helical structure in DNA called denaturation
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* DNA can reform the double helix by the process called renaturation or reannealing
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* B form is a right handed helix with 10 nucleotides base pairs per turn
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* A form a right handed helix with 11 nucleotides base pairs per turn
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* Z form (zigzags) ( rich C&G)
a left handed helix with 12 nucleotides base pairs per turn
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* chromatin in prokaryotes is (single circular supercoiled double stranded)
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* chromatin in eukaryotes (46 chromosome linear double stranded)
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* Eukaryotes heve closed circular DNA in mitochondria
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* genome in prokaryotes are ~(4 million)
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* genome in eukaryotes are ~(3 billion)
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* plasmid (present in prokaryote)
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* plasmid is (nonchromosomal DNA)
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* plasmid (carries genetic information & antibiotic resestant gene )
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DNA Replication in prokaryotic?

⃣مصطلح (Replication)
* Transfere of genetic informations from parental cells to doughter
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⃣* replication occur at S-phase of cell cycle
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⃣مصطلح (semiconservative replication )
* two strands of DNA double helix are separated and each can replication and
produces two daughter molecules

ملاحظة: كل dughter DNA عندها خيط جديد(complementary) وخيط قديم (Template)
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⃣*اهم حاجات تبيهم عملية ال Replication
- Single strand (old strand)
- primer (RNA piece)
- ATP , GTP , CTP , TTP
- Enzymes (polymerase , helicase ,ligase, topoisomerase )

ملاحظة : بالنسبة ل mitochondrial DNA ماتبيش primer
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⃣اهم مثال على prokaryotic replication هي E.coli
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⃣origin of replication (ori C)
* site includes a short sequence
* Exclusively of AT base pairs
* contain 13 base pairs
* start by (GATC)

وفي نقطة البداية هذي حيجيها بروتين اسمه
(dna A protein)
هو اللي بيبدأ في فصل الخيطين ويبي ATP
باش يكون حاجة اسمها replication bubble


ملاحظة : بالنسبة لل eukaryotes عنده أكثر من مكان يبدأ بيه ال replication مش مكان واحد
مهمة هلباااااااااااااااااااااااااااااااااااااااااااا
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⃣مصطلح Replication fork
* When two strands unwind and separate they form V shaped
واللي بدير اللقطة هذي انزيم اسمه helicase
وحيستهلك 2ATP في كل H-bond يكسرها

لكن لما الانزيم هذا بيفتح الخيطين حيسبب مشكلة
واللي هي positive supercoil حيجي بطل انزيم حينقذ الموقف ويفك العقدة اللي تكونت واللي هو انزيم اسمه Topoisomerase
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عندنا نوعين من Topoisomerase
⃣Topoisomerase type I
* cut 1 strand of DNA
* do not use ATP
* inhibited by antitumours drug
* relax negative supercoil

ملاحظة: اللي عند الeukaryotes يخدم على الزوز
positive & negative supercoil
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⃣Topoisomerase type II (gyrase)
* cut 2 strands of DNA
* use ATP
* inhibited by Antibiotics drug
واهم مثال Ciprofloxacin
* relax positive supercoil
ملاحظة: غير موجود في ال human
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⃣both Topoisomerase
* used replication &transcription & recombination
* has endonuclease & ligase
* used tyrosine
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⃣single-stranded -binding proteins
* keep the two strands of DNA seperate
* protect DNA from nucleases enzyme
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⃣* Replication of double strand DNA is bidirectional
يعني حيكون عندنا 2replication fork & 2helicase
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⃣DNA polymerase
* copying the DNA template (parental)
* elongate a new DNA strand
* read from 3 to 5
* synthesis from 5 to 3
* cannot initiate synthesis without prime
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⃣DNA polymerase type III
* هو اللي بيبدأ في تصنيع الخيط الجديد ويركب الnucleotides
* Highly processive enzyme
* has beta subunit
* في كل قاعدة يركبها يحتاج ل 2ATP
* hydrolysis of pp to 2p
* irreversible
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⃣* DNA synthesis stops when that nucleotide is depleted
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⃣primer RNA
* 10 nucleotides long
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⃣primase enzyme
* specific RNA polymerase
* synthesized primer
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⃣Leading strand
* start copied advancing replication fork
* synthesized continuos
* used one primer

⃣Lagging strand
* start copied away replication fork
* synthesized discontinuos
* with small fragments of DNA (okazaki)
* used multi of primer
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⃣proofreading of DNA (misreading)
* يعني لو صار خطأ في تصنيع DNA مثلا ركبنا قاعدة غلط يجي انزيم ينحيها اسمه exonuclease
هذا يخدم من 3 الي 5 ...بعد ماينحيها يجي من جديد DNA polymerase type III ويصنع في مكانها وطبعا نعرفوه يخدم من 5 الي 3 فقط
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