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Which of the following is NOT true about DNA molecular structure? A)DNA strand has inherent polarity dictated by the location of the free phosphate group and the free deoxyribose hydroxyl group. B)Adjacent nucleotides are joined by phosphoester bonds linking 3' and 5' carbons. C)The DNA double helix is built by hydrogen bonding complementarity between nitrogenous bases. D)Guanine-cytosine base pairs are stronger than adenine-thymidine base pairs due to increased hydrogen bonding.

User Paker
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Answer:

The incorrect option is (D) Guanine-cytosine base pairs are stronger than adenine-thymidine base pairs due to increased hydrogen bonding.

Step-by-step explanation:

Deoxyribonucleic acid, also known as DNA, is a molecule that houses the genetic instructions necessary for all known living things to develop, function, and reproduce.

A) The position of the free phosphate group and the free deoxyribose hydroxyl group determines the inherent polarity of the DNA strand. This assertion is accurate. Three elements make up each nucleotide in a DNA strand: a phosphate group, a deoxyribose sugar molecule, and a nitrogenous base. The hydroxyl group of the deoxyribose sugar is connected to the 3' carbon of the neighbouring nucleotide, and the phosphate group is attached to the 5' carbon of one nucleotide. The DNA strand becomes polarised as a result of this configuration.

B) Phosphoester linkages that connect the 3' and 5' carbons of adjacent nucleotides are used to unite them. This assertion is accurate. Phosphodiester bonds hold the nucleotides in a DNA strand together. These bonds link the hydroxyl group on the 3' carbon of one nucleotide's neighbouring nucleotide to the phosphate group of the preceding nucleotide. The DNA strand's backbone is formed by this connection.

C) The nitrogenous bases hydrogen bind with one another to form the DNA double helix. This assertion is accurate. Adenine (A), thymine (T), cytosine (C), and guanine (G) are some of the nitrogenous bases found in DNA. Adenine and thymine form hydrogen bonds, and cytosine and guanine do the same. The DNA double helix structure is maintained by these interactions between complimentary bases. Always creating two hydrogen bonds between Adenine and Thymine and three hydrogen bonds between Cytosine and Guanine, respectively, are adenine and Thymine.

D) Greater hydrogen bonding makes guanine-cytosine base pairs more durable than adenine-thymidine base pairs. This is not true, as stated. Because there are three hydrogen bonds in G-C base pairs compared to two in A-T base pairs, they are actually stronger than adenine-thymine (A-T) base pairs. G-C pairings have a higher stability and stronger bonding because of the added hydrogen bond.

User Plato
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