Video Transcript
The diagram provided shows a simple
outline of the structure of a single DNA nucleotide. Which of the following options
lists the correct components as X, Y, and Z, respectively? (A) X: phosphate group, Y:
deoxyribose sugar, Z: nitrogenous base. (B) X: deoxyribose sugar, Y:
phosphate group, Z: nitrogenous base. (C) X: phosphate group, Y:
nitrogenous base, Z: deoxyribose sugar. (D) X: nitrogenous base, Y:
deoxyribose sugar, Z: phosphate group.
DNA is a biological macromolecule
that carries genetic information. It is made up of two strands that
wrap around each other to form the double helix shape, as we can see here. Let’s zoom in on DNA’s structure so
we can get a better look in order to answer this question. Here, you can see a segment of DNA
with its two strands indicated. Each strand is made up of repeating
subunits called nucleotides. A nucleotide is also what we see in
the provided diagram. There are three components to a
nucleotide. Let’s identify these in both this
diagram and the one that was provided in the question.
A phosphate group is shown here, a
deoxyribose sugar is shown here, and a nitrogenous base is shown here. In DNA, there are four nitrogenous
bases: guanine, represented in orange; cytosine, represented in blue; adenine,
represented in green; and thymine, represented in pink. One base on one strand can pair
with the base on the opposing strand through hydrogen bonding. Guanine pairs with cytosine and
adenine pairs with thymine. This is what holds the two strands
together.
Now that we’ve gone over the basics
of DNA’s structure, we can answer this question. The option that correctly
identifies components X, Y, and Z is given by answer choice (A): X: phosphate group,
Y: deoxyribose sugar, Z: nitrogenous base.
