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In DNA replication why lagging strand formed in a discontinous manner?
Wiki User
∙ 16y ago
There are two main reasons why the lagging strand is synthesized in a discontinuous manner. One you would need to have triphosphates on the 3' side of nuclesoside (3'-dNTPs) when "proofing" the strand, this would require an evolving of an entirely different set of enzymes to make 3'-dNTPs, as well as to use them. Two, you would need to have polymerases that can add a 5'-dNTP to a 5' end of a growing chain, and this is chemically unfavored due to the ease of repairing DNA errors by the 3' exonuclease activity of DNA polymerase.
For the first reason, when DNA polymerase is "proof-reading" it removes an incorrect nucleotide and leaves a 3' OH. If this were the lagging strand, removal of a base would leave a 5' phosphate. Next, for addition of the correct nucleotide, a 5' phosphate bond would be cleaved to add to the 3' OH, this is a high-energy bond that is cleaved, which provides energy for polymerization. If it were the 5' phosphate, the addition would be of the 3'OH on the correct nucleotide. This would be a very slow process because there is no high-energy bond to be cleaved for addition of the 3'OH to the 5' phosphate.
For the second reason, a whole new set of polymerases would have to be made because currently, the 5' dNTPs are added to the 5' triphosphate of the 3'OH on the growing strand. If you were to synthesize in the 3-5 direction, the 3'OH on the 5' dNTP would be added to the 5' triphosphate on the growing end.
Wiki User
∙ 16y ago
Wiki User
∙ 13y agoRemember the double helix is anti-parallel; the strands run in opposite directions. So, the leading strand is continuous, but the lagging strand, being in the other direction has the polymerase working back toward the replication fork and in short pieces. This is a simplified overview; Google replication for possible good animations of this process.
Wiki User
∙ 12y agoThe strands of DNA are antiparallel and complementary strands can only be constructed in a 5' to 3' direction. At the 3' end there is a free hydroxyl group and in order to bond the next nucleotide (which, while floating in the cytosol, has three phosphates in total!!), two phosphates have to be lost so that the energy released can be used to form a bond. This bond forms between the remaining phosphate and the terminal sugar on the growing daughter strand.
Wiki User
∙ 14y agobecause one strand is continuous and the other is not
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What are leading strands?
Leading strands are one of the two newly synthesized DNA strands during DNA replication. They are synthesized in a continuous manner in the 5' to 3' direction, following the replication fork. The leading strand is synthesized in the same direction as the replication fork is moving, allowing for continuous synthesis.
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in a mass formation in the same manner as forming a company mass
How is the battalion (normally) formed when it participates as a separate element of a larger formation or when space is limited?
in a mass formation in the same manner as forming a company mass
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What are leading strands?
Leading strands are one of the two newly synthesized DNA strands during DNA replication. They are synthesized in a continuous manner in the 5' to 3' direction, following the replication fork. The leading strand is synthesized in the same direction as the replication fork is moving, allowing for continuous synthesis.
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What is the DNA polymerase role in DNA replication?
It checks the DNA for errors
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How is DNA able to replicate?
DNA replication is semi-conservative i.e during replication one strand comes fron the parent and another is made complementary to it .The enzymes which helps in its duplication r collectively called REPLIOSOMES or multiple replication enzyme complex. for replication first unwinding should take place and this is done by breaking hydrogen bonding between the nitrogen bases with the help of HELICASES then SSPBs( single strand binding proteins) keep the strands in structured manner so that easy polymerisation of nucleotides should take place and finally TOPOISOMERASES introduce negative coils in the strand by introducing a nick in one of the strands and rejoins the cut again to remove tension on the strand .But It is actually with the help of DNA polymerases and RNA primer that DNA is able is able to replicate.DNA polymerases r of three types namely DNA POLYMARASE 1: IT IS INVOLVED IN REMOVAL OF RNA PRIMER IN THE TEMPLATE STRAND OR PARENT STRAND. it should b noted that no DNA polymerase can initiate DNA replication .it is the RNA primer which initiates DNA replication .it start on adding rna which is then removed by DNA polymerase 1 .to initiate DNA replication is not easy for DNA polymerase as they can commit a lot of mistakes n hence rna primer form rna portion only to make a perfect DNA DNA POLYMERASE2: IT IS TO REPAIR THE DNA DURING INJURY DNA POLYMERASE3:WHICH IS THE REAL REPLICATING ENZYME All of them have endonuclease activity in 3'-5' directionwhich help in proof reading or editing function when its frequency of making mistake is 1 out of 10,000 nucleotides.DNA formation has direction always from 5'-3' since the two strands r anti-parralel hence one(LEADING STRAND) is formed in continuous manner while other(LAGGING) in fragments called OKAZAKI FRAGMENTS
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The planets of our solar system were formed at different times, the earth is known to have formed as a planet about 4.6 billion years ago but other planets in the solar system may have formed earlier or later as they were quite conceivably not formed in the same manner as the earth
How is the battalion formed when it participate as a separate element of a larger formation or when space is limited?
in a mass formation in the same manner as forming a company mass
How is the battalion formed when it participates as a separate element of a larger formation or when space is limited?
in a mass formation in the same manner as forming a company mass
How is the battalion normally formed when it participates as a separate elements of a larger formation or when space is limited?
in a mass formation in the same manner as forming a company mass
How is a battalion normally formed when it participates as a separate element of a larger formation or when space is limited?
in a mass formation in the same manner as forming a company mass
How is the battalion (normally) formed when it participates as a separate element of a larger formation or when space is limited?
in a mass formation in the same manner as forming a company mass
