MCQs on Nucleotide

Nucleotides play an essential role in metabolic and physiological activities. They are made up of a pentose sugar, a nitrogenous base and one or more terminal phosphate group(s). They are building blocks of DNA and RNA. Other than polynucleotides, ATP, NAD, FAD, etc. are also nucleotides.

1. A phosphodiester bond is present in

(a) Nucleic acids in a nucleotide

(b) Monosaccharides in a polysaccharide

(c) Amino acids in a polypeptide

(d) Fatty acids in a diglyceride

2. Uridine present in RNA is

(a) nucleotides

(b) pyrimidine

(c) purine

(d) nucleoside

3. Nucleic acids are a polymer of nucleotide monomeric units. Each nucleotide consists of

(a) base­-sugar-­OH

(b) sugar-­phosphate

(c) base­-sugar-­phosphate

(d) (base­-sugar­-phosphate)x

4. A DNA segment contains 100 Adenine and 100 cytosines, how many nucleotides are present in the segment?

(a) 100

(b) 200

(c) 400

(d) 50

5. Nucleoside contains

(a) base-sugar

(b) base-phosphate

(c) base-sugar-phosphate

(d) sugar-phosphate

6. ATP is a

(a) nucleoside

(b) nucleotide

(c) vitamin

(d) nucleic acid

7. Find the correct statement about phosphodiester linkage between adjacent nucleotides in nucleic acids

(a) 3’-phosphate of one nucleotide joins the 3’-hydroxyl of the next nucleotide

(b) 3’-phosphate of one nucleotide joins the 5’-hydroxyl of the next nucleotide

(c) 5’-phosphate of one nucleotide joins the 5’-hydroxyl of the next nucleotide

(d) 5’-phosphate of one nucleotide joins the 3’-hydroxyl of the next nucleotide

8. The sugar molecule present in nucleotide is

(a) triose

(b) tetrose

(c) pentose

(d) hexose

9. Which of the following nucleotide contains only ribose sugar and not deoxyribose

(a) Thymine – pentose sugar-phosphate

(b) Uracil – pentose sugar-phosphate

(c) Thymine – pentose sugar-phosphate

(d) Cytosine – pentose sugar-phosphate

10. Purine base found in RNA is

(a) Cytosine

(b) Thymine

(c) Guanine

(d) Uracil

Answer

1. (a) 2. (d) 3. (c) 4. (c) 5. (a)
6. (b) 7. (d) 8. (c) 9. (b) 10. (c)

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