Special initiator proteins
This group of proteins includes helicase, which serves as an unzipper by breaking the bonds between the two DNA strands. This unzipping takes place in both directions from the replication origins, creating a replication bubble. The replication is therefore said to be bi-directional. The cell has a complex machinery to perform these tasks. When it is time to replicate, special initiator proteins attach to the DNA at regions called replication origins. These regions are characterised by a weak bond During transcription, enzymes called RNA polymerases build RNA molecules that are complementary to a portion of one strand of the DNA double helix (Figure 3). Figure 3: RNA polymerase at work. RNA polymerase (green) synthesizes a strand of RNA that is complementary to the DNA template strand below it. After the transcription of DNA to mRNA is complete, translation — or the reading of these mRNAs to make proteins — begins. Recall that mRNA molecules are single stranded, and the order of their bases — A, U, C, and G — is complementary to that in specific portions of the cell's DNA. DNA polymerases are a family of enzymes that carry out all forms of DNA replication. DNA polymerases in general cannot initiate synthesis of new strands, but can only extend an existing DNA or RNA strand paired with a template strand. In a cell, DNA replication begins at specific locations, or origins of replication, in the genome. Unwinding of DNA at the origin and synthesis of new strands results in replication forks growing bidirectional from the origin. A number of proteins are associated with the replication fork which helps in terms of the initiation and continuation of DNA synthesis. Most prominently, DNA polymerase synthesizes the new DNA by adding complementary nucleotides to the DNA is made up of two strands and each strand of the original DNA molecule serves as a template for the production of the complementary strand, a process referred to as semiconservative replication. Cellular proofreading and error-checking mechanisms ensure near perfect fidelity for DNA replication. In a cell, DNA replication begins at specific locations, or origins of replication, in the genome. Unwinding of DNA at the origin and synthesis of new strands results in replication forks growing bidirectional from the origin. A number of proteins are associated with the replication fork which helps in terms of the initiation and continuation of DNA synthesis. Most prominently, DNA polymerase synthesizes the new DNA by adding complementary nucleotides to the template strand DNA replication is the action of DNA polymerases synthesizing a DNA strand complementary to the original template strand. To synthesize DNA, the double-stranded DNA is unwound by DNA helicases ahead of polymerases, forming a replication fork containing two single-stranded templates. The process of semiconservative replication for the site of DNA replication is a fork-like DNA structure, the replication fork, where the DNA helix is open, or unwound, exposing unpaired DNA nucleotides for recognition and base pairing for the incorporation of free nucleotides into double-stranded DNA. To be able to replicate, the cell has to unfold and unwind the DNA, and also has to separate the two strands from each other. The cell has a complex machinery to perform these tasks. When it is time to replicate, special initiator proteins attach to the DNA at regions called replication origins. These regions are characterised by a weak bond between the two DNA strands. Replication. Before a cell divides it has to replicate its DNA so that the daughter cell receives a copy of the genome. The DNA helix consists of two complementary DNA strands. Therefore, each of the two strands serves as a template for the construction of the other strand. Under normal conditions the DNA is packed into a compact structure called chromatin. The cell has a complex machinery to perform these tasks. When it is time to replicate, special initiator proteins attach to the DNA at regions called replication origins. These regions are characterised by a weak bond between the two 2. A large team of enzymes and other proteins carries out DNA replication. •The replication of a DNA molecule begins at special sites, origins of replication .•In bacteria, this is a single specific sequence of nucleotides that is recognized by the replication enzymes.
http://www.nobelprize.org/educational/medicine/dna/a/replication/ http://www.nature.com/scitable/topicpage/ribosomes-transcription-and-translation-14120660 https://en.wikipedia.org/wiki/DNA_replication_protein https://en.wikipedia.org/wiki/DNA_replication_protein https://en.wikipedia.org/wiki/Eukaryotic_DNA_replication http://www.nobelprize.org/educational/medicine/dna/a/replication/ http://www.nobelprize.org/educational/medicine/dna/a/replication/ http://mreroh.com/student/APbiodocs/Unit%206%20-%20Molecular%20Genetics/16B-DNAReplication&Repair.pdf
what are the proteins that carry out dna replication