Biochemistry - DNA Structure and Replication - Discussion


Taylor, Woods and Hughes labeled Vicia DNA by allowing new DNA synthesis in the presence of radioactive thymine. After DNA replication (S phase of the cell cycle), it was observed that

[A]. only one chromatid of a chromosome was labeled
[B]. both chromatids of a chromosome were labeled
[C]. both (a) and (b)
[D]. neither chromatid was labeled

Answer: Option B


No answer description available for this question.

B. Ramesh said: (Oct 8, 2013)  
See. DNA in the chromosome was allowed for replication in the presence of radioactive thymine means one strand of DNA will be labelled. After replication also, that strand only having labelled thymine with association of newly formed strand in chromosome. This labelled portion may be present in either of any chromatids. So how it possible to have both chromatids that were labeled ?

Pranjiv Goswami said: (Mar 14, 2014)  
The experiment was carried out to prove semiconservative replication of DNA. That means only one strand/chromatid would be labeled. Please explain if there is any other angle.

Israr said: (Apr 20, 2014)  
Only one/either chromated of chromosome will be labelled.

Devi said: (Nov 14, 2016)  
Only one strand will be label.

Emma. said: (Dec 13, 2016)  
Whenever a parent DNA separates, we get two daughter strands. Therefore, since the DNA was first synthesised in radioactive thymine before undergoing replication, then both chromatid would be labelled.

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