Question

drag each label to the correct location on the image.

arrange the symbols to form a dna molecule.

5
3
adenine
cytosine

Explanation:

Analyze DNA strand directionality

DNA strands are antiparallel.
The top strand runs from \(5'\) to \(3'\).
The bottom strand must run in the opposite direction, from \(3'\) to \(5'\).
Therefore, the bottom-left label box corresponds to the \(3'\) end, and the bottom-right label box corresponds to the \(5'\) end.

Determine arrow direction representation

The top strand has downward-pointing arrows, representing the direction of the strand from \(5'\) to \(3'\).
Since the bottom strand runs in the opposite direction (from right to left, which is \(5'\) on the right to \(3'\) on the left), its directional arrows must point upward.
The arrows represent the nucleotides:

• Downward arrows represent nucleotides on the top strand.
• Upward arrows represent nucleotides on the bottom strand.

Identify base pairing rules

According to Chargaff's rules for complementary base pairing:

• Adenine (A) pairs with Thymine (T).
• Cytosine (C) pairs with Guanine (G).

The key at the bottom shows:

• A red upward arrow is labeled "adenine".
• A brown downward arrow is labeled "cytosine".

This means:

• Red arrows represent Adenine (A).
• Brown arrows represent Cytosine (C).

Determine complementary bases

Using base-pairing rules:

• The complement of Adenine (red arrow) is Thymine (T).
• The complement of Cytosine (brown arrow) is Guanine (G).

Let's match the positions:

• Top strand first position: A blank box is paired with a green upward arrow on the bottom strand.
• Top strand second position: A brown downward arrow (Cytosine) is paired with a blank box on the bottom strand. The complement to Cytosine is Guanine, so the bottom box must contain Guanine.
• Top strand third position: A blank box is paired with a red upward arrow (Adenine) on the bottom strand. The complement to Adenine is Thymine, so the top box must contain Thymine.
• Top strand fourth position: A brown downward arrow (Cytosine) is paired with a blank box on the bottom strand. The complement to Cytosine is Guanine, so the bottom box must contain Guanine.

Now we determine the remaining top-strand blank in the first position:

• The bottom strand has a green upward arrow. Since the top strand has a brown downward arrow (Cytosine) paired with Guanine, and a red upward arrow (Adenine) paired with Thymine, the green arrow must represent Guanine (G).
• Therefore, its complement on the top strand (first box) must be Cytosine (C).

Summarize all label placements

Let's compile the correct labels for all six blank boxes:

• Bottom-left end label: \(3'\)
• Bottom-right end label: \(5'\)
• Top strand, first box: cytosine
• Top strand, third box: thymine
• Bottom strand, second box: guanine
• Bottom strand, fourth box: guanine

Answer:

To form a correct DNA molecule, place the labels into the empty boxes as follows:

• Directional Labels (Ends):
• Bottom-left box: \(3'\)
• Bottom-right box: \(5'\)

• Top Strand Boxes (from left to right):
• First box (above green arrow): cytosine
• Third box (above red arrow): thymine

• Bottom Strand Boxes (from left to right):
• Second box (below brown arrow): guanine
• Fourth box (below brown arrow): guanine