DNA replication

[Dima]

So codons code for amino acids. But during new DNA replication, there are already proteins (enzymes) made of amino acids that sequentially come together to make new DNA. Where do all those enzymes come from (helicase, polymerases, ligases, topoisomerase) in the first place? In order for DNA to occur those enzymes need to be in place first right? Also where does DNA polymerase get its nucleotides to be inserted into the 3' strand? I am a 3' lagging strand.

 

Thanks.

[Horza2002]

Do you mean in a single cell, where do they come from? Or do you mean in the history of life...which ones came first?

[Dima]

I mean @ a single cell.

[alpha2cen]

Do you mean the enzymes folding place from linear protein? And , which cell do you mean, prokaryotic cell or eukaryotic cell?

[Dima]

I realized that "in the first place" i was actually referring to the chicken or egg conundrum. Let me be more specific...In development in general, where do the enzymes of the central dogma of m.b. come from? If anyone has a good link that would point me to information on how exactly those enzymes are synthesized (in a cell) would be great.

 

Thanks.

[alpha2cen]

Polymerase is an important enzyme. There are many kind of polymerases. They are related to the evolution. How fast and how exactly without error is an important factor at DNA duplication.

Edited February 9, 2011 by alpha2cen

[SMF]

I may be confused about what is being asked, but DNA replication occurs in an already existing cell for cell division. Prior to division all the enzymes, and the other proteins that are required (e.g. tubulin for making the mitotic spindle), are made (translated) by the usual method using messenger, transfer, and ribosomal RNA in the cytosol. SM

Edited February 11, 2011 by SMF

[Kethean]

While it is true that all the enzyme in a single cell come from the previous cells...if you are talking about an organismal level, some of the enzymes and such come from the parents haploid cells, or in the case of mammals, some proteins (not necessarily enzymes) can pass from mother to child while in the womb.

[alpha2cen]

While it is true that all the enzyme in a single cell come from the previous cells...if you are talking about an organismal level, some of the enzymes and such come from the parents haploid cells, or in the case of mammals, some proteins (not necessarily enzymes) can pass from mother to child while in the womb.

 

The only DNA always comes from mother is mitochondria DNA. We can use this DNA to prove our ancestors. Important thing is DNA, and we can make other enzymes without cell. This process is called "cell free protein synthesis". This process is used for making useful pure proteins. Practically in the protein making process, separation step is very difficult. So cell free protein synthesis is one of the useful process to obtain highly purified proteins.

[Blahah]

So codons code for amino acids. But during new DNA replication, there are already proteins (enzymes) made of amino acids that sequentially come together to make new DNA. Where do all those enzymes come from (helicase, polymerases, ligases, topoisomerase) in the first place? In order for DNA to occur those enzymes need to be in place first right? Also where does DNA polymerase get its nucleotides to be inserted into the 3' strand? I am a 3' lagging strand.

 

Thanks.

 

It seems a lot of people misunderstood your questions. The enzymes are also synthesized from (ultimately) a DNA template, the first ones come from parental cells and all subsequent ones are made in the cells from amino acids. Yes, in order for DNA replication to occur efficiently you need those enzymes in place, but once the process is running it sustains itself, as long as you provide the raw materials (mineral nutrients + amino acids).

 

The nucleotides are floating around in the cytoplasm. They also come initially from parental cells, and then are synthesized in the cell once the cell machinery is functioning.

Edited February 14, 2011 by Blahah

[Dima]

It seems a lot of people misunderstood your questions. The enzymes are also synthesized from (ultimately) a DNA template, the first ones come from parental cells and all subsequent ones are made in the cells from amino acids. Yes, in order for DNA replication to occur efficiently you need those enzymes in place, but once the process is running it sustains itself, as long as you provide the raw materials (mineral nutrients + amino acids).

 

The nucleotides are floating around in the cytoplasm. They also come initially from parental cells, and then are synthesized in the cell once the cell machinery is functioning.

 

...what i was looking for, thank you!