Q1. A mutation in DNA generates a UGA stop codon in the middle of the RNA coding for a particular protein. A second mutation in the cell leads to a single nucleotide modify in a tRNA that allows the correct translation of the protein. The altered tRNA translates the UGA as tryptophan. What nucleotide varies has probably occurred in the mutant tRNA molecule? What consequences will the presence of such a mutant tRNA have for the translation of the normal genes in this cell?

Q2. What is the chemical reaction for aerobic respiration and what will be the reactants and products, I'm stuck on where to find out the reply to this question I should be reading right over it in my book.