Question

for questions 1 - 5, complete each statement by writing in the correct word or words. 1. the building blocks of dna are nucleotides. 2. nucleotides in dna are made of three basic components: a sugar called deoxyribose, a nitrogenous base, and a phosphate group. 3. dna contains four kinds of nitrogenous bases: adenine, thymine, guanine, and cytosine. 4. in dna, nucleotides can be joined in any order. 5. the nucleotides in dna are joined by covalent bonds. lesson 12.2 • workbook a • copyright © by pearson education, inc., or its affiliates. all rights reserved. 184

Explanation:

1. Nucleotides are the building blocks of DNA.
2. Each DNA nucleotide consists of deoxyribose sugar, a phosphate group, and a nitrogen - containing base.
3. The four nitrogenous bases in DNA are adenine, thymine, cytosine, and guanine.
4. Nitrogenous bases in DNA are joined by hydrogen bonds in base - pairing.
5. Nucleotides in DNA are joined by covalent bonds to form a polynucleotide chain.

Answer:

1. nucleotides
2. deoxyribose; phosphate group; nitrogen - containing base
3. adenine; thymine; cytosine; guanine
4. hydrogen
5. covalent