DNA and RNA differ only in the sugar and one base
- The idea
- Predict
- See it
- Why
- Check
The idea
“Thymine, uracil, ribose and deoxyribose are all nucleotide parts, so any of them can go in DNA or RNA.”
On paper, thymine, uracil, ribose and deoxyribose blur together. When you write fast, it's easy to grab one from the wrong list.
The short version
The mistake: Thymine, uracil, ribose and deoxyribose are all nucleotide parts, so any of them can go in DNA or RNA.
What's actually true: DNA uses deoxyribose and A, T, G, C. RNA uses ribose and A, U, G, C. Both use the same phosphate.
- Every nucleotide has a phosphate, a five-carbon sugar and a nitrogenous base. The base attaches at the sugar's 1' carbon and the phosphate at the 5' carbon.
- The sugars differ at the 2' carbon. Ribose has a hydroxyl group, -OH, there. Deoxyribose has only a hydrogen.
- A, G and C are in both. DNA pairs adenine with thymine, and RNA uses uracil instead.
- When you write a strand, pick one list and stay in it.
On the exam: DNA gets deoxyribose and T. RNA gets ribose and U. The phosphate and A, G, C are shared.