Part A. Conceptual Questions

• Answer the following questions by Shuguang Zhang:

• How many molecules of amino acids do you take with a piece of 500 grams of meat? (on average an amino acid is ~100 Daltons)

Average 20% of meat is protein. Therefore, 500 grams of meat have 100 grams of protein. Now the question is, how many molecules of amino acids are present in 100 grams of protein?

It is given that one amino acid is 100 daltons. We know 1 dalton means 1 g/mol. Therefore, one amino acid is 100 g/mol. Since one amino acid is 100 g/mol (100 gram amino acid is 1 mol), therefore one gram of amino acid contains 0.01 mol amino acid. Therefore, 100 grams of protein (amino acids) contain 100*0.01 = 1 mol amino acid.

As we all know, 1 mol means 6.0210^23, therefore 6.0210^23 molecules of amino acids I take with a piece of 500 grams of meat. (Took help from chatgpt)

• Why humans eat beef but do not become a cow, eat fish but do not become fish?

Because we eat the foods and digest them via digestive system. The digested proteins or nucleotides are not incorporated into our genome.

• Why there are only 20 natural amino acids?

Because 20 amino acid is enough to go through different combinations and permutations and generate all the proteins out there, even more.

• Can you make other non-natural amino acids? Design some new amino acids.

The question already asked me to design new amino acids, so yeah I can definitely make other non-natural amino acids (Hehehe). Here I have designed some rare amino acids (d-amino acids).

• Where did amino acids come from before enzymes that make them, and before life started?