Question

which of these is the best description of codons? codons are part of the cell membrane that decide which types of molecules can enter a cell. codons are specific sequences of three nucleotides on mrna that code for specific amino acids codons are large sections of dna that have escaped the nucleus and are trying to bind to uses.

Explanation:

To determine the best description of codons, we analyze each option:

1. The first option is incorrect because cell membrane components (like transport proteins) regulate molecule entry, not codons.
2. The second option is correct. Codons are indeed sequences of three nucleotides on mRNA that correspond to specific amino acids during translation.
3. The third option is incorrect as codons are on mRNA (not large DNA sections escaping the nucleus) and do not bind to viruses in this context.

Answer:

B. Codons are specific sequences of three nucleotides on mRNA that code for specific amino acids