Question

Adenine is the last nucleotide at the 3' end of one strand of DNA. It is base-paired with thymine on the other DNA strand. Which of the following statements about these nucleotides is FALSE? If the adenine has an unlinked 3' hydroxyl group, then the thymine must have an unlinked 5' phosphate group The adenine and the thymine are each bonded to the previous nucleotide in the strand by a phosphodiester bond The two nucleotides are located on DNA strands that are parallel to each other There are two hydrogen bonds between the adenine and thymine nitrogenous bases.

Answer 1

The two nucleotides are located on DNA strands that are parallel to each other

Step-by-step explanation:

Deoxyribonucleic acid, commonly known as DNA, is one of the two types of nucleic acids. It is a molecule composed of a nitrogenous base, pentose sugar and a phosphate group. According to the information given in this question, Adenine is the last nucleotide at the 3' end of one strand of DNA. The following are factual about the nucleotide;

- Since DNA is a double-stranded molecule, the Adenine nucleotide will be base-paired with Thymine nucleotide (complementary base pairing) on the other DNA strand.

- Since complementary DNA strands are opposite to one another, this means that if the adenine has an unlinked 3' hydroxyl group, then the thymine must have an unlinked 5' phosphate group.

- Nucleotides in a DNA strand are joined to one another via a covalent bond called PHOSPHODIESTER BOND. Hence, the adenine and the thymine are each bonded to the previous nucleotide in the strand by a phosphodiester bond.

- In the complementary base pairing between two nucleotide bases, there are two hydrogen bonds between the adenine and thymine nitrogenous bases i.e. A=T.

- DNA strands that make up a molecule are complementary and opposite to one another, hence, they are said to be ANTIPARALLEL.