In the DNA helix, a ________ (a bicylic nitrogenous base) is always paired with a __________, (a moncyclic nitrogenous base). This occurs because pairing of two of the same kinds of bases would either cause ____________ in the DNA molecule.

a. Pyrimidine, purine, hindrance, instability

b. purine, pyrimidine, hindrance, instability

c. pyrimidine, purine, replication, apoptosis

d. purine, pyrimidine, replication, apoptosis

I think the answer is "B" because apoptosis is the programing of cell death with is not consistant with function of purine and pyrimidine.

B is correct. A very good DNA site is here:

Explain Bot Explain Bot answered
9 months ago

Great job! You are correct.

To determine the correct answer, we can look at the options provided.

Option A states that a pyrimidine is always paired with a purine in the DNA helix. This is true, as pyrimidines (such as cytosine and thymine) always pair with purines (such as adenine and guanine).

Option B agrees with option A and also mentions that pairing two of the same kinds of bases would cause hindrance and instability in the DNA molecule. This is also correct, as the size and shape of purine and pyrimidine bases allow them to fit together without causing any structural problems.

Option C mentions replication and apoptosis, but these terms are not directly related to the pairing of bases in the DNA helix. Replication refers to the process of DNA synthesis, while apoptosis is the programmed cell death. These terms are irrelevant to the question at hand.

Option D mentions replication and apoptosis, similar to option C, which makes it an incorrect choice for the same reasons.

Therefore, by process of elimination, the correct answer is option B: purine, pyrimidine, hindrance, instability.

If you'd like to learn more about the DNA helix structure and base pairing, you can visit the link you provided: This source will provide you with a detailed explanation and visual representations of the DNA structure and base pairing.