What is a major difference between messenger RNA ($m\mathrm{RNA}$) molecules and transfer RNA ($t\mathrm{RNA}$) molecules?

• A. $m\mathrm{RNA}$ is involved in protein synthesis, whereas $t\mathrm{RNA}$ is not.
• B. $m\mathrm{RNA}$ carries the genetic code from DNA to the ribosome, while $t\mathrm{RNA}$ brings amino acids to the ribosome.
• C. $m\mathrm{RNA}$ is double-stranded, while $t\mathrm{RNA}$ is single-stranded.
• D. $m\mathrm{RNA}$ is found only in the nucleus, whereas $t\mathrm{RNA}$ is found only in the cytoplasm.

Answer: (B)

Verified step by step guidance

1. Identify the roles of mRNA and tRNA in the process of protein synthesis. mRNA carries the genetic information from DNA to the ribosome, where proteins are synthesized. tRNA, on the other hand, is responsible for bringing the appropriate amino acids to the ribosome during protein synthesis.
2. Understand the structural differences between mRNA and tRNA. mRNA is typically a single-stranded molecule that is linear and carries the genetic code in the form of codons. tRNA, however, has a cloverleaf structure and is also single-stranded but folds into a specific shape to function in protein synthesis.
3. Consider the location of mRNA and tRNA within the cell. mRNA is synthesized in the nucleus and then transported to the cytoplasm where ribosomes are located. tRNA is found in the cytoplasm where it performs its role in protein synthesis.
4. Clarify any misconceptions about the double-stranded nature of mRNA. mRNA is not double-stranded; it is single-stranded, similar to tRNA, but they have different functions and structures.
5. Summarize the major difference: mRNA carries the genetic code from DNA to the ribosome, while tRNA brings amino acids to the ribosome, facilitating the translation of the genetic code into a protein.