Describe what happens when you heat-denature protein, compared to heat-denaturin
ID: 53283 • Letter: D
Question
Describe what happens when you heat-denature protein, compared to heat-denaturing DNA. Why is only one of these processes reversible?
Write a hypothesis for whether the procedure you performed in the lab isolates RNA as well as DNA. How would you test this hypothesis? Can you find an analytical method that would distinguish between RNA and DNA? How could you use this method to test your hypothesis?
What purpose do the papain, SDS, and ethanol serve? What do you predict would happen if you substituted each of these for water? Justify your prediction in each case with a chemical/ physical argument (e.g. water has a higher viscosity than ethanol so the wooden stick would be harder to spin)
Explanation / Answer
Tertiary and quaternary structures of protein are formed with covalent bonds and weak hydrogen bonds. If heat denaturation breaks the covalent bonds then they cannot be renatured again, and hence in most of the cases protein denaturation is irreversible.
But in case of DNA, the two strands of DNA is bound with hydrogen bonds, when cooled the hydrogen bonding is reformed again. So, the DNA denaturation is reversible.