1)
Phosphodiester bonds in DNA are advantageous because they are more stable chemically when
compared with ester bonds. This stability is rendered because of the negative charge present on a
phosphodiester bond. This charge repels similarly charged ions like OH- ions which have the
ability to carry out a nucleophilic hydrolysis reaction and hence break the bond. Hence such
hydrolysis cannot occur in a phosphodiester bond and it is more stable.
2)
The semi-conservative nature of DNA replication means that during DNA replication, each
daughter DNA has one strand inherited from the parent as it is and the other strand of the double
helix is newly synthesised. This was initially proved by Meselson and Stahl in 1958.
The experiment can be described in the following steps:
These results confirmed the hypothesis made by the 2 scientists as the initial band of heavy DNA
indicated all the DNA of same kind. The intermediate band in second generation indicated that
half the DNA was original (with heavy isotope) and the other half was with normal N. And then
the increase in band-width of normal N containing cells indicated that all new cells now
manufactured their DNA from medium having normal N source.
3)
Topoisomers are DNA molecules with same chemical structure but different topology i.e. they
have different geometrical properties and spatial relations. There are two major Topoisomers of
DNA:
Solution
1)
Phosphodiester bonds in DNA are advantageous because they are more stable chemically when
compared with ester bonds. This stability is rendered because of the negative charge present on a
phosphodiester bond. This charge repels similarly charged ions like OH- ions which have the
ability to carry out a nucleophilic hydrolysis reaction and hence break the bond. Hence such
hydrolysis cannot occur in a phosphodiester bond and it is more stable.
2)
The semi-conservative nature of DNA replication means that during DNA replication, each
daughter DNA has one strand inherited from the parent as it is and the other strand of the double
helix is newly synthesised. This was initially proved by Meselson and Stahl in 1958.
The experiment can be described in the following steps:
These results confirmed the hypothesis made by the 2 scientists as the initial band of heavy DNA
indicated all the DNA of same kind. The intermediate band in second generation indicated that
half the DNA was original (with heavy isotope) and the other half was with normal N. And then
the increase in band-width of normal N containing cells indicated that all new cells now
manufactured their DNA from medium having normal N source.
3)
Topoisomers are DNA molecules with same chemical structure but different topology i.e. they
have different geometrical properties and spatial relations. There are two major Topoisomers of
DNA:.
1) Phosphodiester bonds in DNA are advantageous because they are m.pdf
1. 1)
Phosphodiester bonds in DNA are advantageous because they are more stable chemically when
compared with ester bonds. This stability is rendered because of the negative charge present on a
phosphodiester bond. This charge repels similarly charged ions like OH- ions which have the
ability to carry out a nucleophilic hydrolysis reaction and hence break the bond. Hence such
hydrolysis cannot occur in a phosphodiester bond and it is more stable.
2)
The semi-conservative nature of DNA replication means that during DNA replication, each
daughter DNA has one strand inherited from the parent as it is and the other strand of the double
helix is newly synthesised. This was initially proved by Meselson and Stahl in 1958.
The experiment can be described in the following steps:
These results confirmed the hypothesis made by the 2 scientists as the initial band of heavy DNA
indicated all the DNA of same kind. The intermediate band in second generation indicated that
half the DNA was original (with heavy isotope) and the other half was with normal N. And then
the increase in band-width of normal N containing cells indicated that all new cells now
manufactured their DNA from medium having normal N source.
3)
Topoisomers are DNA molecules with same chemical structure but different topology i.e. they
have different geometrical properties and spatial relations. There are two major Topoisomers of
DNA:
Solution
1)
Phosphodiester bonds in DNA are advantageous because they are more stable chemically when
compared with ester bonds. This stability is rendered because of the negative charge present on a
phosphodiester bond. This charge repels similarly charged ions like OH- ions which have the
ability to carry out a nucleophilic hydrolysis reaction and hence break the bond. Hence such
hydrolysis cannot occur in a phosphodiester bond and it is more stable.
2)
The semi-conservative nature of DNA replication means that during DNA replication, each
daughter DNA has one strand inherited from the parent as it is and the other strand of the double
helix is newly synthesised. This was initially proved by Meselson and Stahl in 1958.
The experiment can be described in the following steps:
2. These results confirmed the hypothesis made by the 2 scientists as the initial band of heavy DNA
indicated all the DNA of same kind. The intermediate band in second generation indicated that
half the DNA was original (with heavy isotope) and the other half was with normal N. And then
the increase in band-width of normal N containing cells indicated that all new cells now
manufactured their DNA from medium having normal N source.
3)
Topoisomers are DNA molecules with same chemical structure but different topology i.e. they
have different geometrical properties and spatial relations. There are two major Topoisomers of
DNA:
