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What does a DNA molecule look like?

Answer 1

A molecule of DNA looks like a spiral staircase. The steps of the stair represents paired bases attached by hydrogen bonds.

Biologists describe DNA as a double helical molecule , because:

there are two chains of nucleotides running side by side (but in opposite directions, hence antiparallel and double stranded) due to presence of hydrogen bonds between them
the double stranded molecule could have resembled a ladder, but it becomes twisted: so the molecule looks like a spiral ladder (hence described as helical)

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Answer 2

Julian Aguilar

A DN molecule is a double helix structure composed of two long chains of nucleotides. Each nucleotide consists of a sugar molecule, a phosphate group, and a nitrogenous base (adenine, thymine, cytosine, or guanine). The two chains are held together by hydrogen bonds between complementary base pairs: adenine pairs with thymine, and cytosine pairs with guanine.

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.