March 1, 2030. A unique creature has been discovered during exploration of outer
ID: 166459 • Letter: M
Question
March 1, 2030. A unique creature has been discovered during exploration of outer space. Recently, its genetic material has been isolated and analyzed. This material is similar in some ways to its chemical makeup. It contains in abundance the 4-carbon sugar erythrose and a molar equivalent of phosphate groups. It contains six nitrogenous bases: adenine (A), guanine (G), thymine cytosine (C), hypoxanthine (H), and xanthine (X). These bases exist in the following relative proportions: A = T = H C = G = X X-ray diffraction studies have established a regularity in the molecule and a constant diameter of about 30 A Based on the data, what base-pairing properties must exist for hypoxanthine (H) and xanthine (X)? Select all that apply. H base pairs with either A or T X base pairs with either A or T H and X base pair with each other H base pairs with either C or G X base pairs with either Cor GExplanation / Answer
Answer: (a) and (e)
Explanation:
According to Chargaff's rule, in DNA, the proportion of the pyrimidine base to purine base follows a 1:1 ratio. Adenine = Thymine and Cytosine = Guanine. Hence we get the A-T and G-C base pairing in regularity in the DNA double helix.
Following the above-mentioned principle, in the newly discovered creature, since A=T=H and C=G=X, there would be base pairing of H with either A and T and there would be base pairing of X with either C or G.