Video Transcript
A list of properties of nucleic
acids is provided. (I) Contain a ribose sugar. (II) Are comprised of many
repeating nucleotides. (III) Contain the nitrogenous bases
ATGC. (IV) Contain a phosphate group. (V) Contain a deoxyribose
sugar. Which of these properties are
common to both DNA and RNA? (A) I, III, and V; (B) I and IV;
(C) II and IV; or (D) I, III, and IV.
DNA and RNA are nucleic acids. They are polymers made up of
strings of nucleotides and store genetic information. We need to learn some more
information about the differences and similarities between these two molecules in
order to answer our question. First, let’s discuss the structure
of these nucleic acids, which both consist of many nucleotides bound together by
phosphodiester bonds. This tells us that property (II),
are comprised of many repeating nucleotides, is common to DNA and RNA.
Each nucleotide is made up of a
phosphate group, a sugar, and a nitrogen-containing base, which is sometimes called
a nitrogenous base. This also confirms that property
(IV), contain a phosphate group, is also common to both DNA and RNA. Both RNA and DNA contain the
nitrogenous bases A, G, and C.
Now, let’s take a look at the
differences between DNA and RNA. DNA stands for deoxyribonucleic
acid, and the sugars in nucleotides of DNA are deoxyribose sugars. On the other hand, the sugar found
in each nucleotide of RNA, which is short for ribonucleic acid, is a ribose
sugar. This tells us that property (I) and
property (V) are not common to both DNA and RNA.
For statement (III), we need to
look at which nitrogenous bases the two nucleic acids contain. A nucleotide of DNA might contain
any one of the nitrogenous bases A, G, C, or T. However, each nucleotide of RNA may
either contain the nitrogenous base A, G, C, or U. As RNA does not contain the
nitrogenous base T, which is short for thymine, property (III) is not common to both
DNA and RNA.
Now that we know which of the
properties of nucleic acids provided in the question are common to both DNA and RNA,
we can answer the question correctly. They are both composed of many
repeating nucleotides and contain a phosphate group. So the correct answer is (C), II
and IV.
