The bases A, G, U, C, I (inosine) all occur at the 5^' positions of anticodons in tRNAs. (a) Whi

step 1 Let us talk about the first question and the answer will be ionocine. This is because it is form

The bases A, G, U, C, I (inosine) all occur at the 5^'...

The bases $A, G, U, C, I$ (inosine) all occur at the $5^{\prime}$ positions of anticodons in tRNAs. (a) Which base can pair with three different bases at the $3^{\prime}$ positions of codons in $\mathrm{mRNA}$ ? (b) What is the minimum number of tRNAs required to recognize all codons of amino acids specified by codons with complete degeneracy?

The bases $A, G, U, C, I$ (inosine) all occur at the $5^{\prime}$ positions of anticodons in tRNAs.
(a) Which base can pair with three different bases at the $3^{\prime}$ positions of codons in $\mathrm{mRNA}$ ?
(b) What is the minimum number of tRNAs required to recognize all codons of amino acids specified by codons with complete degeneracy?

Key Concepts

tRNA Anticodon-Codon Interaction

The interaction between the anticodon of tRNA and the codon of mRNA is pivotal in translating genetic information into proteins. Each tRNA carries a specific anticodon that pairs with the codon on the mRNA complementarily, following the directionality (5' to 3') of each strand. The rules governing these interactions, including canonical pairing and wobble pairing, are crucial for the accuracy and efficiency of protein synthesis.

Degeneracy of the Genetic Code

The genetic code is said to be degenerate because most amino acids are encoded by more than one codon. This redundancy means that fewer tRNAs are necessary because multiple codons can be recognized by the same tRNA through wobble base pairing. Complete degeneracy involves cases where the third base of the codon does not affect the amino acid specified, thus enabling a more economical use of the tRNA population.

Wobble Hypothesis

The wobble hypothesis explains the flexibility in the base pairing between the 5' anticodon nucleotide of a tRNA and the 3' codon nucleotide of mRNA. It accounts for the fact that a single tRNA can often pair with more than one codon, which helps explain how fewer tRNAs can recognize all 61 sense codons. This flexibility is particularly evident in the third position of the codon (and the corresponding first position of the anticodon), where non-standard base pairings, such as those involving inosine, commonly occur.

Inosine

Inosine is a modified nucleotide found in the anticodon of certain tRNAs, particularly at the 5' position. Unlike the standard bases, inosine has the capacity to base pair with multiple bases (commonly adenine, uracil, and cytosine) at the 3' position of the codon, making it a key player in the wobble hypothesis. This ability allows one tRNA molecule to recognize several codons and contributes to the genetic code's degeneracy.

Transcript

Please give Ace some feedback