I was wondering if anyone can clarify the answer to this question for me:
Double-stranded DNA can adfopt one of three helical conformations depending on the nucleotide makeup of the molecule and the amount of hydration. The nucleotide base pairs in a DNA helix are arranged like steps in a spiral staircase. Each one is rotated a few degrees from the previous base pair.
Table 1 AVerage Helical Twist between Adjacent Nucleotide Pairs (Mean and standard Deviation, in Degrees)
Conformation Helical twist
A 33.1 +/- 6
B 35.9 +/- 4
Z 29.9 +/- 1
Investigating the properties of a strand of DNA, researchers determined that there were 12 nucleotide base pairs for every complete 360 degree turn of the helix. The conformation of the DNA strand was:
A) A, not B or Z
B) B, not A or Z
C) Z, not A or B
D) A or B, not Z
The correct answer was C, because each turn (360/12) is about 30 degrees.
However, I think the proper answer should be D). If there are 12 base pairs per 360 that means there are 11 twists between adjacent pairs, and thus ~33 per twist between adjacent base pairs. This would a mean that A or B is correct but not Z.
From empirical stand point, 1 standard deviation can not be justified as being significantly different with p < 0.05. Thus the data could not be used to justify whether the structure is A or Z (and arguably B) if the theoretical turn is 30 degrees.
Double-stranded DNA can adfopt one of three helical conformations depending on the nucleotide makeup of the molecule and the amount of hydration. The nucleotide base pairs in a DNA helix are arranged like steps in a spiral staircase. Each one is rotated a few degrees from the previous base pair.
Table 1 AVerage Helical Twist between Adjacent Nucleotide Pairs (Mean and standard Deviation, in Degrees)
Conformation Helical twist
A 33.1 +/- 6
B 35.9 +/- 4
Z 29.9 +/- 1
Investigating the properties of a strand of DNA, researchers determined that there were 12 nucleotide base pairs for every complete 360 degree turn of the helix. The conformation of the DNA strand was:
A) A, not B or Z
B) B, not A or Z
C) Z, not A or B
D) A or B, not Z
The correct answer was C, because each turn (360/12) is about 30 degrees.
However, I think the proper answer should be D). If there are 12 base pairs per 360 that means there are 11 twists between adjacent pairs, and thus ~33 per twist between adjacent base pairs. This would a mean that A or B is correct but not Z.
From empirical stand point, 1 standard deviation can not be justified as being significantly different with p < 0.05. Thus the data could not be used to justify whether the structure is A or Z (and arguably B) if the theoretical turn is 30 degrees.
