Hi there! I'm really fascinated with genes. I have several questions, and I do hope you will be able to answer them! It will really aid my understanding in genes!

Does each protein contain all 20 amino acids?

What happens to mRNA and tRNA after the polypeptide chain is formed?

“Having more than one possible code for an amino acid is called redundancy or degeneracy of the code. It acts to buffer the effect of mutations because a change to a single base may not necessarily change the amino acid coded for.” - Since there is a change in the base sequence but the amino acid is still the same, is this called a same sense mutation?

Do all genes start and end with the triplets complementary to the start and stop codons?

“AUG is the start signal. It codes for the amino acid methionine. This amino acid is usually cleaved off the completed polypeptide chain.” - So the amino acid methionine is hardly part of a protein since it is cleaved off?

Do mutations occur on the template strand or coding strand of DNA?

Thank you so much for your time!


All proteins don't contain all amino acids. mRNA and tRNA are most likely degraded and the nucleotides recycled. Most genes start and end with the start and stop codons but perhaps not all. Methionine may or may not be cleaved off in all proteins. Mutations can occur anywhere. Yes to your definition of a same sense mutation.