Dangerously Thin:

A Case Study on the Genetic Code

1. Someone with a CYP2C9 genetic mutation would be at a much higher risk for overdosing on a prescribed drug like Warfarin because the enzyme needed to metabolize the drug is not functioning properly. The drug cannot be metabolized or broken down, causing it to become toxic.

2. DNA replication requires a messenger and a decoder carried out by the RNA. Messenger RNA (mRNA) carries the coded information where protein synthesis occurs, transfer RNA (tRNA) decodes mRNA's message for amino acid sequence in the polypeptide to be built. In Henry's case, the code is mutated and goes through the process of gene replication, which results in the wrong triplet code for the enzyme needed for breaking down the drugs. (Marieb, 2015)

3. Within each gene only one of the two strands of DNA, called the template strand is transcribed. The other complementary strand, referred to, as the non-template remains untranscribed. RNA polymerase reads the DNA template strand and produces the RNA transcript by adding nucleotides. (Purves, 2004)

4. a.) The sequence of the template strand would be AATGGCTCT.
b.) The DNA sequence code contains the triplet codes.
c.) After the sequence is transcribed the sequence would be UUACCGAGA. Thymine is replaced Uracil.
d.) Assuming that there is no start codon or termination signal three amino acids would be made.

5. a.) The nucleotide sequence on the template strand would be GAA.
b.) The mRNA condon that results after the triplet is transcribed as CUU.
c.) The anticodon of the tRNA molecule is GAA.
d.) The amino acid that would be carried by the tRNA molecule is Leucine.

6. a.) The template strand will now be ACA.
b.) The mRNA strand after being transcribed will now be UGU.
c.) The anticodon on the tRNA molecule that is complementary to the mRNA condon is ACA.
d.) The amino acid that would be carried by the tRNA molecule is Cytesine.

7. Henry's enzyme loses its function due to the change in amino acid. One mutated amino acid in the peptide changed the entire protein. Causing the structure to fold improperly, which in enzyme function, structure is a vital component. (Purves, 2004)

8. a.) Henry's first triple code ATT can be changed to ATC or ATA without resulting in a change in the amino acid, which is Isoleucine. Henry's second triplet code, CGT can be changed to CGU, CGA CGG to maintain the amino acid arginine. (Purves, 2004)
b.) There are five triplet codes that would not change the amino acid.
c.) The third position of the triplet code was changed for both DNA codes.
d.) From the pattern above I would conclude that if a mutation occurred in the first second position there would always be a change in the amino acid. If a change occurred on the third position it may or may not effect a change in the amino acid coding.

Marieb, E., & Joehn, K. (2015). Human Anatomy and Physiology. United States: Pearson
Education, Inc.

Purves W., Sadava, D., Orians, G., & Heller, C. (2004). Life: The Science of Biology. 7th Edition. United States: Sinauer and Freeman Education, Inc.