DNA replication and recombination
- Created by: Breedelahaye2020
- Created on: 16-10-20 18:40
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- For transmission to occur, genetic material must be copied.
- During this process, DNA replication, orignal DNA strands are used as templates for syntheis of new DNA strands
Structural overview of DNA replication
- DNA is a double heloix composed of two DNA strands
Existing DNA strands Act as Templates for synthesis of new strands
- Durig the replication process, two complementary strands of DNA come apart and serve as a template strands, or parental strands for synthesis of two new strands of DNA.
Bacterial chromosomes contain a single origin of replication
- A replication fork is the site where the parental DNA strand have seperated and new daugher strands are being made.
Replication is initiated at the origin of replication
- Considerable research has focused on the origin of replication oin E.coli. The origin is named for origin of Chromosome replication.
Synthesis of RNA primers bia primase
- Leading strand, made in the same direction as the replication fork is moving in, a single primer is made at the origin of replication.
- Lagging strand, made in short fragmebts in the opposite direction from the movement of the replication fork; multiple primer are made
Synthesis of DNA
- An enzyme known as DNA polymerase is responsible for synthesing the DNA of the leading and lagging strands.
- Enzyme catalyze the formation of covelent bonds between adjacent nucleotides, thereby making the new daughter strands.
Syntehsis of the leading and lagging strands is diffrent
- DNA polymaerase can attach nucleotides only in the 5 to 3 directions, not in the 3 to 5 direction.
Certain enzymes of DNA replication bind to each other to form a complex
- DNA helicase and primase are physically bound to each other to form a complex known as a primosome.
DNA polymerase is a processive enzyme that uses deoxyribonucleoside triphosphates
- Nucleotide about to be attached to the growing strand is a dNTP containing three phosphate groups attached at at the 5 -carbon atom of deoxyribose.
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