Question

identify the number of possible mrna codons that exist
hint: how many three letter combinations exist?

Explanation:

Step1: Determine the number of choices for each position

Each mRNA codon is a three - letter combination, and for each of the three positions (first, second, third) of the codon, there are 4 possible nucleotides (U, C, A, G).

Step2: Use the multiplication principle

The multiplication principle of counting states that if there are \(n_1\) ways to do the first task, \(n_2\) ways to do the second task, and \(n_3\) ways to do the third task, then the total number of ways to do all three tasks together is \(n_1\times n_2\times n_3\).
Here, \(n_1 = 4\) (choices for the first letter), \(n_2=4\) (choices for the second letter), and \(n_3 = 4\) (choices for the third letter).
So the total number of possible mRNA codons is \(4\times4\times4=4^{3}=64\).

Answer:

The number of possible mRNA codons is \(\boldsymbol{64}\)