DNA is a long polymer of _______

[Molecular-Basis-of-Inheritance] [class-xii ]

• Nucleosides
• Nucleotides
• Amino acids
• Fatty acids
Correct Option: B  [ Nucleotides ]

Remark: Nucleic acids like DNA are polymers made up of monomeric units called nucleotides.

A nucleotide consists of a nitrogenous base, a pentose sugar, and a _______ group.

[Molecular-Basis-of-Inheritance] [class-xii ]

• Hydroxyl
• Carboxyl
• Phosphate
• Methyl
Correct Option: C  [ Phosphate ]

Remark: A nucleotide has three components: a nitrogenous base, a pentose sugar, and a phosphate group.

The nitrogenous bases Adenine and Guanine are classified as _______

[Molecular-Basis-of-Inheritance] [class-xii ]

• Pyrimidines
• Purines
• Nucleosides
• Proteins
Correct Option: B  [ Purines ]

Remark: Adenine and Guanine are purines, which are nine-membered double-ring structures.

Cytosine, Thymine, and Uracil are classified as _______

[Molecular-Basis-of-Inheritance] [class-xii ]

• Purines
• Pyrimidines
• Amino acids
• Sugars
Correct Option: B  [ Pyrimidines ]

Remark: Cytosine, Thymine, and Uracil are pyrimidines, which are six-membered single-ring structures.

Thymine is present in DNA, whereas _______ is present in RNA.

[Molecular-Basis-of-Inheritance] [class-xii ]

• Adenine
• Guanine
• Uracil
• Cytosine
Correct Option: C  [ Uracil ]

Remark: Uracil replaces Thymine in RNA.

A nitrogenous base is linked to the pentose sugar through a _______ linkage.

[Molecular-Basis-of-Inheritance] [class-xii ]

• Phosphodiester
• N-glycosidic
• Peptide
• Hydrogen
Correct Option: B  [ N-glycosidic ]

Remark: The nitrogenous base is linked to the pentose sugar via an N-glycosidic linkage to form a nucleoside.

When a phosphate group is linked to the 5' OH of a nucleoside, a _______ is formed.

[Molecular-Basis-of-Inheritance] [class-xii ]

• Nucleotide
• Nucleic acid
• Amino acid
• Polypeptide
Correct Option: A  [ Nucleotide ]

Remark: Adding a phosphate group to a nucleoside forms a nucleotide.

Two nucleotides are linked through a 3'-5' _______ linkage.

[Molecular-Basis-of-Inheritance] [class-xii ]

• N-glycosidic
• Hydrogen
• Phosphodiester
• Peptide
Correct Option: C  [ Phosphodiester ]

Remark: Nucleotides are joined by phosphodiester bonds to form a polynucleotide chain.

The backbone of a polynucleotide chain is formed due to _______ and phosphates.

[Molecular-Basis-of-Inheritance] [class-xii ]

• Nitrogenous bases
• Sugars
• Amino acids
• Hydrogen bonds
Correct Option: B  [ Sugars ]

Remark: The backbone consists of alternating sugar and phosphate groups.

5-methyl uracil is another name for _______

[Molecular-Basis-of-Inheritance] [class-xii ]

• Adenine
• Guanine
• Thymine
• Cytosine
Correct Option: C  [ Thymine ]

Remark: Thymine is chemically 5-methyl uracil.