RNA pairs with the template and matches the coding strand
- The idea
- Predict
- See it
- Why
- Check
The idea
“The RNA has the same sequence as its template, so the strand that reads like the RNA is the template.”
The word template makes it sound like the strand the RNA copies. It works more like a mold. The RNA forms against it and comes out complementary.
The short version
The mistake: The RNA has the same sequence as its template, so the strand that reads like the RNA is the template.
What's actually true: The RNA base-pairs with the template strand, so it matches the coding strand, with U where the DNA has T.
- RNA polymerase reads the template 3' to 5' and builds RNA 5' to 3'. Each new base pairs with the DNA base across from it: A with T, U with A, G with C.
- So the RNA is complementary to the template. It has the same sequence as the other strand, the coding strand, with U in place of T.
- Gene sequences are usually written as the coding strand, so you can read the codons straight off them.
On the exam: The RNA pairs with the template and reads like the coding strand, with U for T.