Label: DNA, RNA, and the missing nucleotides marked on the diagram_ TOH (0p RNA polymerase 4 / 13 Key Adenine C = Cytosine Guanine Thymine Uracil
The Correct Answer and Explanation is:
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To generate the correct RNA sequence from a DNA template strand, we follow the base pairing rules:
- DNA’s Adenine (A) pairs with RNA’s Uracil (U)
- DNA’s Thymine (T) pairs with RNA’s Adenine (A)
- DNA’s Cytosine (C) pairs with RNA’s Guanine (G)
- DNA’s Guanine (G) pairs with RNA’s Cytosine (C)
In the image, the RNA polymerase is synthesizing an RNA strand using the DNA template. Suppose the DNA template strand (the one being copied) contains the bases: 3′ – TAC GGT ACG TTA – 5′
Then the complementary RNA sequence would be: 5′ – AUG CCA UGC AAU – 3′
Let’s walk through the reasoning behind this process.
Transcription is the cellular mechanism where RNA is synthesized using one strand of DNA. This occurs in the nucleus of eukaryotic cells. The enzyme RNA polymerase reads the template DNA strand from its 3′ to 5′ direction and builds the RNA strand in the 5′ to 3′ direction by matching complementary RNA nucleotides.
Unlike DNA, RNA does not use thymine. Instead, uracil is incorporated wherever adenine appears in the DNA template. This is a crucial distinction that helps cells identify RNA molecules. The growing RNA strand detaches once transcription is complete, ready to undergo further processing like splicing or translation depending on the type of RNA produced.
In this diagram, the missing nucleotide on the RNA strand opposite DNA’s adenine (A) would be uracil (U), and opposite cytosine (C) would be guanine (G), and so forth. Identifying these complementary bases ensures that the genetic information is accurately transferred from DNA to RNA, a fundamental step in gene expression and protein synthesis
