Thinking question re dna/rna structure: certain chemical agents acting on dna could convert cytosine to uracil through the process of deamination (chopping off the amino group). This mutation is routinely repaired by the existing repair mechanism (uracil is removed and it gets replaced by cytosine). Knowing this, how would you explain why dna contains thymine and not uracil. Unpaired uracils will lead to permanent sequence changes as they would be paired with adenine during replication. Cytosine deamination would gradually lead to a decrease in gc base pairs and an increase in a:u base pairs. Later on, cytosine deamination could eliminate all g:c base pairs and the genetic code that depends on them. Bacterial genome has no repetitive sequences -> whole genome is one unique sequence calf genome has lots of repetitive sequences -> its unique sequences are more complex than: coli however, explain c value paradox.