DNA Replication

[Andiio]

My book describes a certain area of the process as:
"The bases exposed on the separated strands then act as a template to which new nucleotides attached by H-bonds b/w complementary base pairs. These bases then undergo a condensation polymerisation reaction to form two exact copies of the orig DNA double helix."

My question relates to the second sentence - don't the NUCLEOTIDES and not the BASES undergo condensation polymerisation reactions to form the DNA molecules?

Thanks!

[scocliffe09]

My book describes a certain area of the process as:
"The bases exposed on the separated strands then act as a template to which new nucleotides attached by H-bonds b/w complementary base pairs. These bases then undergo a condensation polymerisation reaction to form two exact copies of the orig DNA double helix."

My question relates to the second sentence - don't the NUCLEOTIDES and not the BASES undergo condensation polymerisation reactions to form the DNA molecules?

Thanks!

Strictly speaking, the nitrogenous base is a part of the nucleotide, and you're right in that the polyester bonds are formed between phosphate and sugar groups, so it is more correct to say the nucleotides undergo condensation polymerisation than it is to say the bases undergo condensation polymerisation. That said, I think it's commonly accepted that when talking about a "base" forming a nucleic acid, you mean a nucleotide (not that I would write that on the exam, just want you to be aware of it), so don't get too caught up about it.

[Andiio]

My book describes a certain area of the process as:
"The bases exposed on the separated strands then act as a template to which new nucleotides attached by H-bonds b/w complementary base pairs. These bases then undergo a condensation polymerisation reaction to form two exact copies of the orig DNA double helix."

My question relates to the second sentence - don't the NUCLEOTIDES and not the BASES undergo condensation polymerisation reactions to form the DNA molecules?

Thanks!

Strictly speaking, the nitrogenous base is a part of the nucleotide, and you're right in that the polyester bonds are formed between phosphate and sugar groups, so it is more correct to say the nucleotides undergo condensation polymerisation than it is to say the bases undergo condensation polymerisation. That said, I think it's commonly accepted that when talking about a "base" forming a nucleic acid, you mean a nucleotide (not that I would write that on the exam, just want you to be aware of it), so don't get too caught up about it.

Ah okay, thanks for that! I'm just a little bit worried about all the technicalities and nomenclature etc! So on the exam would it be best to write bases or nucleotides? Or should I simply just expand on it in more detail?

Also, when asked why a DNA molecule is able to produce a replica of itself, (I understand the process) but I'm not sure if I understand the book's answer to it 100%: they said that "nitrogen base pairing also ensures that the opposite polymer strand is produced from each half of the double helix". Am I reading too into it? :\

Thanks again!

[luken93]

I've got a link that (I think) has a good little video about how the replication process occurs, if I don't do it tonight remind me

[Graphite]

I supposed they only used "bases" for simplicity. But you can think of it as that its already implied since bases are part of a nucleotide. I would go with nucleotide as that describes the entire complex.

[scocliffe09]

My book describes a certain area of the process as:
"The bases exposed on the separated strands then act as a template to which new nucleotides attached by H-bonds b/w complementary base pairs. These bases then undergo a condensation polymerisation reaction to form two exact copies of the orig DNA double helix."

My question relates to the second sentence - don't the NUCLEOTIDES and not the BASES undergo condensation polymerisation reactions to form the DNA molecules?

Thanks!

Strictly speaking, the nitrogenous base is a part of the nucleotide, and you're right in that the polyester bonds are formed between phosphate and sugar groups, so it is more correct to say the nucleotides undergo condensation polymerisation than it is to say the bases undergo condensation polymerisation. That said, I think it's commonly accepted that when talking about a "base" forming a nucleic acid, you mean a nucleotide (not that I would write that on the exam, just want you to be aware of it), so don't get too caught up about it.

Ah okay, thanks for that! I'm just a little bit worried about all the technicalities and nomenclature etc! So on the exam would it be best to write bases or nucleotides? Or should I simply just expand on it in more detail?

Also, when asked why a DNA molecule is able to produce a replica of itself, (I understand the process) but I'm not sure if I understand the book's answer to it 100%: they said that "nitrogen base pairing also ensures that the opposite polymer strand is produced from each half of the double helix". Am I reading too into it? :\

Thanks again!

stick with nucleotide, in this instance, because, as I said, the phosphodiester bonds are forming between phosphate and sugar groups.
All that second line means is that, because of the fact that A and T form 2 H bonds and C and G form 3 H bonds, and C and T are pyrimidine (one ring) whereas A and G are purine (two rings), C can only H bond to G and A to T - which ensures that the complementary strand is indeed complementary. "opposite polymer strand" just means the strand running in the opposite direction with a complementary base sequence to the template strand. I think you were probably reading too much into it.