Nucleic Acid Models: B-DNA and tRNA
📖 Background
The B-DNA is the usual structure found in cells. It is a right-handed molecule with base pairs that are perpendicular from the backbone.
On the other hand, the tRNA is a necessary RNA in protein expression (Translation). Its structure is necessary for the proper translation of mRNA to amino acids.
⚙️ The following are resources to get a visual of these structures.
1. RCSB links - These links direct you to the crystal structure (the actual structure derived from X-ray crystallography) of the nucleic acids. Rotate and zoom in on their structures through these links: B-DNA, tRNA.
2. Paper Models - If you have a printer available, you may want to have a tactile experience by printing these instructions to make your own paper model of DNA and tRNA.
🤔 Thought Questions
From these models (virtual or paper), try answering/ reflecting on these questions.
- How is the handedness of the DNA molecule determined?
- Can you identify the major and minor grooves in the model? What are the functions of these grooves?
- In a B-DNA, how many base pairs comprise one complete turn? How does this differ from the A and Z forms?
- Describe the 1o, 2o, and 3o structures of tRNA.
- In tRNA, what types of bonds stabilize each level of organization?
- Can you identify the parts of the tRNA that are crucial for translation?
- Can 2o and 3o structures exist for single-stranded nucleic acids?