Iowa Core Mathematics
Sense-Making Activities
Description and Correlation
Title: DNA/RNA
Grade: 9-12
Iowa Core
Characteristics of
Effective Instruction
Iowa Core Standards for
Mathematical Practice
Iowa Core Standards for
Mathematical Content:


Teaching for Understanding
Rigor and Relevance
 Make sense of problems and persevere in solving them.
 Reason abstractly and quantitatively.
 Model with mathematics.
S-CP-9: (+) Use permutations and combinations to compute probabilities of
compound events and solve problems.
Grades K-8
Domain/Standards
Grades 9-12
Conceptual Category/
Domain/Standards
Sense-Making Activity
1) A deoxyribonucleic acid (DNA) molecule is made up of a “chain”
(sequence) of smaller molecules called nucleotides. The nucleotides
contain the bases A(adenine), C(cytosine), G(guanine), and T(thymine).
In 1952, building on their predecessors’ research in genetics, James
Watson and Francis Crick realized that the DNA molecule was too thick to
be a single strand. After trying several models, they made one in which
two strands were wrapped around each other (a twisted ladder). Today
this twisted-two-strand model (called a double helix) is accepted as the
correct structure for DNA. In addition, in the early 1950s American
scientist Edwin Chargoff made an important discovery about the four
nitrogenous bases. Chargoff’s work led to the discovery that across the
rungs of the DNA twisted ladder Adenine always pairs with Thymine and
Cytosine always pairs with Guanine. Given this information, how many
different 5 molecule sequences are possible?
2) A ribonucleic acid (RNA) is a messenger molecule associated with
deoxyribonucleic acid (DNA). RNA is made up of a “chain” (sequence) of
smaller molecules called nucleotides. The nucleotides contain the bases:
U(uracil), C(cytosine), G(guanine), and A(adenine). It is difficult to
observe exactly what an entire RNA chain looks like, however it is
possible to observe fragments of a chain by breaking it up with certain
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enzymes. Knowledge about these fragments can sometimes determine
the makeup of an entire chain of RNA. The “G-enzyme” will break an
RNA chain after each G(guanine) link. The “U-C-enzyme” will break an
RNA chain after every U(uracil) and every C(cytosine). Consider the RNA
chain AGUGGAUUGUCAUGA. A G-enzyme will break this chain into the
fragments AG, UG, G, AUUG, UCAUG, and A. While the U-C-enzyme will
break the same chain into the fragments AGU, GGAU, U, GU, C, AU, and
GA. Unfortunately, the fragments of a broken-up chain may be mixed up
and in the wrong order.
Suppose an RNA chain is broken by a G-enzyme into the fragments AUG,
AAC, CG, and AG. While the U-C-enzyme breaks the same RNA chain
into the fragments GC, GAAC, and AGAU. What is the complete RNA
chain of 10 bases?
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