Chapter 4, Problem 1P

Interpretation Introduction

Interpretation:

The following blanks should be filled with suitable substances as mentioned below:

……….. Adenosine	…….. Uridine
……….. Cytidine 5'-monophospahe	…….. Deoxycytidine 5'triphosphate
……….. Guanine	……… Deoxyuridine
……….. Thymine	………. Guanosine 5'-diphosphate
……….. Deoxyguanosine	………. Thymidine triphosphate

1. A nucleobase
2. A ribonucleoside
3. A ribonucleotide
4. A deoxyribonucleoside
5. A deoxyribonucleotide
6. A dinucleotide

Concept Introduction:

A nucleobase is a biological compound. It is basically as nitrogen containing base. They form nucleosides and nucleotides which are made up of nucleic acid. The only difference between a nucleoside and nucleotide is presence of phosphate group in the nucleotides. The common between them is a nitrogenous base and a five-carbon sugar. If a nucleoside contain ribose as a component then it is known as ribonucleoside, where ribose is carbohydrate (pentose monosaccharide) with molecular formula ${\text{C}}_{\text{5}}{\text{H}}_{\text{10}}{\text{O}}_{\text{5}}$. Similarly, ribonucleoside is ribose containing nucleotide. In ribose, if a hydroxyl group is replaced by hydrogen, it become deoxyribose. Thus, deoxyribonucleoside and deoxyribonucleotide are nucleoside and nucleotide with deoxyribose as a component. If there are two units of each of the nitrogenous base, sugar and phosphate group present in a compound it is known as dinucleotide.

Answer:

(b) A ribonucleoside-Adenosine	(b) A ribonucleoside -Uridine
(c) A ribonucleotide-Cytidine 5'-monophosphate	(e) A deoxyribonucleotide- Deoxycytidine 5'triphosphate
(a) A nucleobase-Guanine	(d) A deoxyribonucleoside-Deoxyuridine
(a) A nucleobase-Thymine	(c) A ribonucleotide- Guanosine 5'-diphosphate
(d) A deoxyribonucleoside-Deoxyguanosine	(e) A deoxyribonucleotide-Thymidine triphosphate

Explanation of Solution

The structure of Adenosine and uridine are as follows:

Adenosine Uridine

Both are ribonucleoside as they contain ribofuranose attached by glycosidic bond to the purine nucleoside.

The structure of Cytidine 5'-monophosphate and guanosine 5'-diphosphate are as follows:

Cytidine 5'-monophosphate Guanosine 5'-diphosphate

The nucleoside cytidine and guanine are attached to phosphoric acid through ester linkage, thus, they form a nucleotide. There is also a pentose sugar ribose hence, they are classified as a ribonucleotide. There is one phosphate group in cytidine 5'-monophosphate and two phosphate groups in guanosine 5'-diphosphate.

Guanine and thiamine both are nucleobase, as they are nitrogen containing bases. They are found in nucleic acids DNA and RNA.

The structures are as follows:

Guanine Thymine

Deoxyguanosine and deoxyuridine are deoxyribonucleoside as they contain deoxyribose without phosphate group.

The structures are as follows:

Deoxyguanosine Deoxyuridine

Deoxycytidine 5'triphosphate and thymidine triphosphate are deoxyribonucleotide as they contain deoxyribose with phosphate group attached to nucleoside.

The structures are as follows:

Deoxycytidine 5'triphosphate Thymidine triphosphate