Chapter 17, Problem 17.30UKC

Answer Problem 17.29 for the following dinucleotide.

Interpretation Introduction

Interpretation:

Bases present in the below dinucleotide has to be identified.

Concept Introduction:

The skeleton structure of base in nucleic acid generally consists of a nitrogen atom in it. There are two types of bases that are pyrimidine base and purine base.

(a) Pyrimidine base consists of one ring and is present in uracil (U), cytosine (C), and thymine (T).

(b) Purine base consists of two rings and is present in adenine (A) and guanine (G).

Explanation of Solution

The given structure contains two nucleotides that are nucleotide 1 and nucleotide 2 and is drawn as follows:

Nucleotide 1 contains a base with one ring in it thus is a pyrimidine base. Therefore, the name of base is thymine. Whereas nucleotide 2 contains a base with one ring in it thus is a pyrimidine base. Therefore, the name of base is cytosine.

Interpretation Introduction

Interpretation:

The $5^{\prime }$ end and $3^{\prime }$ end of below dinucleotide has to be labeled.

Concept Introduction:

Nucleotide is defined as basic unit for formation of nucleic acid that is essential for completion of metabolic reactions in body. The three basic components of nucleotide are as follows:

1 Nitrogen-containing base

2 Pentose sugar

3 Phosphate group

Dinucleotide is a polymer that is composed of two nucleotide units either of DNA or RNA that is bonded to each other through a covalent bond.

Explanation of Solution

Phosphate group is attached to $5^{\prime }$ end of the nucleotide. Hence it is a phosphate end. While $\text{OH}$ group is bonded to $3^{\prime }$ end of the nucleotide. The two nucleotides are joined together through $5^{\prime }$ and $3^{\prime }$ linkage. Thus, $5^{\prime }$ end and $3^{\prime }$ end in below dinucleotide is labeled as follows:

Interpretation Introduction

Interpretation:

Three or four letter abbreviation of below dinucleotide has to be identified.

Concept Introduction:

Nucleotides are named accordingly as follows:

1 Identify the type of sugar unit attached is ribose or deoxyribose. If in the structure of nucleoside there is $\text{OH}$ group at $\text{C}{\text{2}}^{\prime }$ then the sugar is ribose sugar and if there is no $\text{OH}$ group at $\text{C}{\text{2}}^{\prime }$ then it is deoxyribose sugar and prefix deoxy is used.

2 Identify the name of the different nitrogen bases present in the molecule. There are two types of bases that are pyrimidine base and purine base.

(a) Pyrimidine base consists of one ring and is present in uracil, cytosine, and thymine.

(b) Purine base consists of two rings and is present in adenine and guanine.

3 Nucleosides with pyrimidine bases end with the suffix $\text{-idine}$ and purine bases end with $\text{-osine}$.

4 Identify the number of carbon atom to which phosphate group is attached. The prefix is added as mono, di or tri for numbers of phosphate groups present in the nucleotide.

Abbreviation is assigned with respect to the type of sugar. For ribose sugar, 3 letter abbreviation is used and for deoxyribose sugar, 4 letter abbreviation is used followed by d as a prefix.

Explanation of Solution

In the below structure of dinucleotide, base, phosphate group and monosaccharide are labeled as follows:

For nucleotide 1:

Name of nucleotide is assigned as follows:

1 There is no $\text{OH}$ group at $\text{C}{\text{2}}^{\prime }$ therefore, it is a deoxyribose sugar.

2 It contains one ring, therefore, it is a pyrimidine base called thymine and suffix used is $\text{-idine}$.

3. Phosphate group is attached to $5^{\prime }$ carbon of sugar and only one phosphate group is present. Therefore mono is added before phosphate group.

Hence, the name of the given nucleotide is $\text{thymidine }{5}^{\prime }\text{-monophosphate}$ and abbreviation used is TMP.

For nucleotide 2

Name of nucleotide is assigned as follows:

1 There is no $\text{OH}$ group at $\text{C}{\text{2}}^{\prime }$ therefore, it is a deoxyribose sugar.

2 It contains one ring therefore is a pyrimidine base called cytosine and suffix used is $\text{-idine}$.

3. Phosphate group is attached to $5^{\prime }$ carbon of sugar and only one phosphate group is present. Therefore mono is added before phosphate group.

Hence, the name of the given nucleotide is $\text{cytidine }{5}^{\prime }\text{-monophosphate}$ and abbreviation used is CMP.

Interpretation Introduction

Interpretation:

Whether the below nucleotide is ribonucleotide or deoxyribonucleotide has to be explained.

Concept Introduction:

Refer to part (c).

Explanation of Solution

Since in the structure of dinucleotide both the nucleotide does not contain an $\text{OH}$ group at $\text{C}{\text{2}}^{\prime }$, therefore, the sugar is deoxyribose sugar. Hence, the given nucleotide is deoxyribonucleotide. The structure of dinucleotide is as follows:

Interpretation Introduction

Interpretation:

Name of the below dinucleotide has to be identified.

Concept Introduction:

Refer to part (c).

Explanation of Solution

The given structure contains two nucleotides that are nucleotide 1 and nucleotide 2 and is drawn as follows:

For nucleotide 1:

Name of nucleotide is assigned as follows:

1 There is no $\text{OH}$ group at $\text{C}{\text{2}}^{\prime }$ therefore, it is a deoxyribose sugar.

2 It contains one ring, therefore, it is a pyrimidine base called thymine and suffix used is $\text{-idine}$.

3. Phosphate group is attached to $5^{\prime }$ carbon of sugar and only one phosphate group is present. Therefore mono is added before phosphate group.

Hence, the name of the given nucleotide is $\text{thymidine }{5}^{\prime }\text{-monophosphate}$ and abbreviation used is TMP.

For nucleotide 2:

Name of nucleotide is assigned as follows:

1 There is no $\text{OH}$ group at $\text{C}{\text{2}}^{\prime }$ therefore, it is a deoxyribose sugar.

2 It contains one ring, therefore, it is a pyrimidine base called cytosine and suffix used is $\text{-idine}$.

3. Phosphate group is attached to $5^{\prime }$ carbon of sugar and only one phosphate group is present. Therefore mono is added before phosphate group.

Hence, the name of the given nucleotide is $\text{cytidine }{5}^{\prime }\text{-monophosphate}$ and abbreviation used is CMP.

Therefore, the name of the dinucleotide is TC.