Question

1. the three basic parts of a nucleotide are ______.carboxyl group, deoxyribose sugar, nitrogenous basephosphate, hexose sugar, nitrogenous basephosphate, deoxyribose sugar, nitrogenous basephosphate, deoxyriboses sugar, glycerol2. which of these are base - paired correctly?c - tg - tc - at - a3. the two strands of dna are joined to each other or held together by ____.covalent bondinghydrophilic interactionvan der waals forceshydrogen bonding4. the two strands of the dna molecule are ______antiparallelidenticalalternating palindromicparallel

Explanation:

1. A nucleotide consists of a phosphate group, a deoxyribose sugar (in DNA), and a nitrogenous base. Carboxyl group is not part of a nucleotide. Hexose sugar (a six - carbon sugar) is incorrect as it's deoxyribose (a five - carbon sugar). Glycerol is not part of a nucleotide.
2. In DNA base - pairing, adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G). So, T - A is correctly base - paired.
3. The two strands of DNA are held together by hydrogen bonds between the nitrogenous bases. Covalent bonding is within a single strand (between nucleotides). Hydrophilic interaction and van der Waals forces are not the main forces holding the two strands together.
4. The two strands of the DNA molecule are antiparallel. One strand has a 5' - 3' orientation, and the other has a 3' - 5' orientation. They are not identical (they are complementary), not alternating palindromic, and not parallel.

Answer:

1. phosphate, deoxyribose sugar, nitrogenous base
2. T - A
3. hydrogen bonding
4. antiparallel