3. Radioactive isotopes are commonly used as a means to measure incorporation into biological molecules. A researcher measured the incorporation of 32P-labeled ADP or 32-P labeled ATP into RNA. He added various nucleotide mixtures to an E. coli extract that catalyzed RNA synthesis. The table below lists the added components along with the observed radioactivity incorporated into the RNA (cpm = counts per minute).
Reaction components
cpm incorporated
1. ADP
690
2. ADP, UDP, CDP, GDP
1800
3. ATP
790
4. ATP, UTP, CTP, GTP
3920
3a. Based on your knowledge from this chapter and the data above, what enzyme is likely present in the E. coli extract?
3b. Why does reaction #4 has the greatest cpm value compared to other reactions?
4a. The genetic code was discovered to consist of 64 codons due to the fact that the 4 RNA nucleotides are read in triplets (43 = 64). Why would a 2 nucleotide codon system have been insufficient?
3. Radioactive isotopes are commonly used as a means to measure incorporation into biological molecules. A researcher measured the incorporation of 32P-labeled ADP or 32-P labeled ATP into RNA. He added various nucleotide mixtures to an E. coli extract that catalyzed RNA synthesis. The table below lists the added components along with the observed radioactivity incorporated into the RNA (cpm = counts per minute).
| Reaction components | cpm incorporated |
| 1. ADP | 690 |
| 2. ADP, UDP, CDP, GDP | 1800 |
| 3. ATP | 790 |
| 4. ATP, UTP, CTP, GTP | 3920 |
3a. Based on your knowledge from this chapter and the data above, what enzyme is likely present in the E. coli extract?
3b. Why does reaction #4 has the greatest cpm value compared to other reactions?
4a. The genetic code was discovered to consist of 64 codons due to the fact that the 4 RNA nucleotides are read in triplets (43 = 64). Why would a 2 nucleotide codon system have been insufficient?
