Nucleic Acid Models: B-DNA and tRNA

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📖  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. 

  1. How is the handedness of the DNA molecule determined? 
  2. Can you identify the major and minor grooves in the model? What are the functions of these grooves? 
  3. In a B-DNA, how many base pairs comprise one complete turn? How does this differ from the A and Z forms? 
  4. Describe the 1o, 2o, and 3o structures of tRNA.
  5. In tRNA, what types of bonds stabilize each level of organization?
  6. Can you identify the parts of the tRNA that are crucial for translation? 
  7. Can 2o and 3o structures exist for single-stranded nucleic acids?