Polynucleotide chain of DNA contains

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Q: 1 (CDS-I/2017)
Polynucleotide chain of DNA contains

question_subject: 

Science

question_exam: 

CDS-I

stats: 

0,38,42,55,15,9,1

keywords: 

{'polynucleotide chain': [0, 0, 0, 1], 'dna': [3, 1, 1, 2], 'ribose sugar': [0, 0, 0, 1], 'phosphate group': [1, 0, 0, 1], 'deoxyribose sugar': [1, 0, 0, 1], 'nitrogenous base': [0, 0, 0, 1]}

The correct answer is option 1: a nitrogenous base, deoxyribose sugar, and phosphate group.

In DNA, the building blocks of the nucleotide are composed of three main components: a nitrogenous base, a deoxyribose sugar, and a phosphate group. The nitrogenous base can be adenine (A), thymine (T), cytosine (C), or guanine (G). The deoxyribose sugar is a five-carbon sugar molecule that provides the backbone of the DNA strand. Lastly, the phosphate group is a molecular group consisting of phosphorus and oxygen atoms.

Option 2 is incorrect because it mentions ribose sugar instead of deoxyribose sugar. Ribose sugar is present in RNA, not DNA.

Option 3 is incorrect because it mentions both ribose sugar and deoxyribose sugar, which is not accurate.

Option 4 is incorrect because it mentions a nitrogenous base and a phosphate group only, omitting the essential deoxyribose sugar component.

Therefore, the correct answer is option 1: a nitrogenous base, deoxyribose sugar, and phosphate group.