Question

question 1 of 10
which best describes how scientists found the human gene that makes insulin?
a. they mixed the amino acids in insulin with the mrna in the liver.
b. they figured out the dna sequence from the amino acid sequence.
c. they used bacteria that naturally produced insulin to locate the gene.
d. they figured out the amino acid sequence from the mrna sequence.

Explanation:

Scientists determined the DNA sequence for the human insulin - producing gene by working backward from the known amino acid sequence of insulin. This is based on the principles of the genetic code, where each amino acid is encoded by a specific nucleotide sequence (codons) in DNA. Option A is incorrect because mixing amino acids with mRNA in the liver is not a valid method for gene discovery. Option C is wrong as bacteria do not naturally produce human insulin (although recombinant bacteria can be engineered to do so). Option D has the process reversed; typically, the amino acid sequence is known first (from protein analysis), and then the DNA sequence is deduced.

Answer:

B. They figured out the DNA sequence from the amino acid sequence.