Question

15. Short answer Suppose a point mutation changes a stretch of DNA that RNA polymerase is about to
transcribe. The mutation changes the base sequence from TAA to TGA. Explain the effect/result this
mutation will have following transcription and translation (use your codon chart), and explain why such
a small change could lead to disease or even death. (10cr)

Answer 1

Explanation:

Point mutations lead to the change of one amino acid to another. TAA and TGA are DNA and their RNA equivalents are AUU and ACU. AUU codes for isoleucine and ACU codes for threonine. Changes such as this can cause a protein to completely fold differently. The non-covalent interactions may change as the polarity of exchanged amino acids changes, causing that shape change. Shape changes mean function changes, and when a protein does not function properly, the cell does not function properly. This can lead to a cascading effect of disfunction, or disease.