Molecular Basis

Question 1

Basic unit of DNA + structure
3 types on bonds
Backbone + ends

Answer 1

Nucleotide
1. Phosphate
2. Sugar deoxyribose [ o removed from C2]&raquo_space;»in rna ribose
3. Nitrogenous bases
Purine ( adenine + guanine )
Pyrimidine (cytosine + thymine)
Thymine aka 5 methyl uracil
In rna uracil

NGlycosidic linkage
Nitrogenous base - OH of c1

Phosphoester linkage
P grp- OH of c5

Phosphodiester linkage
Nucleotide- Nucleotide

Backbone =
Phosphodiesterbond+Sugar + Pi

5* free phosphate grp
3* free OH

Question 2

Erwin chargaff

Answer 2

Not applicable to ss RNA
> A+G = C+T [purine =pyrimidine]
>amount of sugar =amount of pi
>no.of pi = no.of nitrogenous bases
>A+T/C+G = const 1.52H 0.93E

Question 3

Salient features of dna

Answer 3

> 2 chains Backbone + nitrogenous bases projected inwards
anti polarity 5>3 3>5