Question

D. d Which nucleotides are named correctly? CH3 HN HN N 00 8-= -OH CO -OHCHIN H OH OH OH OH 5-TMP I СН3 HT 3-GMP II NH HOH.C N oe O-D-OH2C oo 0 OH 20-P=0 O CO-P=0 OH OH eo 5-GDP IV 3-TDP MI Choose one answer A. I,III B. II, III C. III, IV D. II, IV 6 Which statement about the base mole-percent composition of DNA is true? 30

Answer 1

the correct answer is option A (i.e., structure 1 and structure 3 are named correctly).

the solution is given below :-

nucleotide are named as

• firstly the number 3' or 5' which represent the carbon of sugar to which phosphate group is connected.
• then nitrogenous base which is present is structure is written.
• ( in naming of base suffix either sine or dne is added as follows

1. adenine - adenosine
2. Guanine - guanosine
3. Thymine - thymidine
4. uracil - uridine
5. cytosine - cytidine)

• then phosphate is written with prefix mono,di ,tri on basis of number of phosphate group present .
• Note - if sugar is deoxyribose then the prefix deoxy is written before base name. For ribose no such thing is used .

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Nucleotides Hitrogenous base + pentose sugar + phosphate Nitrogenous boss NHL Adenine (A) :- at I Guanine (G) - HN NHL cytosinec) Gracil (U): - HAI Thymine (T) crz H

Pentose Sugar ribose used, Generally ribose 2-deoxy HOLC oh D-ribose - 2 OH OH 2-Deoxyribose Holhe /-2 no has t-2 M but -OH both -H I OH 3 pou Phosphate (It Can link P to sugar either at or 5 sition Sugar called 3 position of c posit 3' or 5' respectively thus

I ) - Thymine q @ o ·P o ųe o OH OH Mono phosphate at C-5 ribose sugar So Name :- 5 - Thymidinemonophosphate 5' - IMP 1) W Guanine H - - 0. 0-HC P 11. 0 Monophosphate on OH at C -5 ribose Name - 5' - Guanosinemonophosphate 15 - GMP

9 Thymine 1:) HN Thohe ribose on -P= Diphosphate at C-3 Do o amo Name :- 3 - Thymidine Diphosphate or 3 - TDP TV-) NHL Adenine 3 Z- he diphosphate OH On at c-5 ribose Name 5'- Adenosine diphosphate 5 - ADP