milu
Forum Junior
Topics: 18
Posts: 35
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Describe the process of DNA replication in bacteria, and explain what the term Semiconservative means in relation to this process?
please explain both of this questions in detail......thank you so much <:help:> :?:
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truth is great yet truthful living is the greatest....
Mili
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| milu
Forum Junior
Topics: 18
Posts: 35
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noone has an answer for it...i knew its hard ... 
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truth is great yet truthful living is the greatest....
Mili
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| Malaysian
Forum Guru
Topics: 28
Posts: 778
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The former is a very long explanation....so I will answer the second part.....semiconservative means that the 2 strands of DNA in the parent cell are separated and used as templates each where the nucleotide are added complementary to it....resulting in the formation of 2 DNAs.....each of the daughter DNA has a parent strand and a newly made strand....thats what semiconservative is.
To answer the former you need to be familiar with prokaryotic replication.....key words... shine dalgarno sequence,rho factor,sigma factor,DNA polymerase is 1,2,3(I think!!)....ribosome units are 50s and 30s(in eukaryotes its 60s and 40s...I think!!)....theres no splicing of mrna and so the rna thats formed is ready for translation.Also the first amino acid used in the formation is formyl methionine.Lastly in prokaryotic replication there is only 1 ori signal and so 1 replication bubble....in eukaryotes theres multiple.These are the basics which I can summarize.
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| niti
Forum Guru
Topics: 36
Posts: 499
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Hi milu,
DNA Repliation
Purpose is to create 2 daughter DNA mole. that are identical to parental DNA.This is achieved by semi-conservative replication.
semi-conservative replication
uses each of the parental strands of DNA as a template for directing the synthesis of one new daughter molecule.
DNA replication is a 5 step process
1)DNA-unwinding proteins or helicase unwind the DNA duplex.Fork-type structure formed ( replication fork).Topoisomerase cut and reseal the DNA ( strain imposed by unwinding).
2)Primase makes RNA primers that are complimentary to the template strands of DNA.this process moves in 5’ to 3’ direction.
3)At 3’ end of primer ,DNAP adds nucleotides to the 3’-OH ( leading strand)which grows in 5’ to 3’ direction,but the synthesis occurs discontinuously,producing small fragments known as Okazaki fragments.
4)Conversion of Okazaki fragments to a continuous strandThis is accomplished by 2 reactions.When DNA polymerase III approaches another RNA primer,it dissociates and DNA polymease I enters.DNA polymersae removes the ribonucleotides one at a time from the 5’ end ( exonuclease activity) .then adds complimentary deoxyribonucleotides to fill in the gaps.
5)Finally,DNA ligase forms a phoshodiester bond between two adjacent DNA fragments.
Hope it will help.
THANKS
niti
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| niti
Forum Guru
Topics: 36
Posts: 499
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Hi milu,
I really want to understand DNA replication process.As you said during Oct/11 ANATOMY chat that your professor explained it and now you understood very well .Can you please post it here ? I will be really thankful to you.
niti
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