DNA Denaturation?

Question

Why are nucleic acids more resistant to denaturation due to high temperatures relative to proteins?

Answer 1

NA's have simpler shapes then proteins because they have less molecules. They have less places to denaturalize.

Answer 2

I suppose it would be because proteins rely on amino acid sequence AND hydrogen bonds AND disulfide bonds in order to be structurally functional. You only need the linear sequence in DNA, although it is only supported by 2 or 3 hydrogen bonds per nucleotide.
There are, however, proteins that need extreme tempurature to denature, such as Taq polymerase, which is the DNA polymerase in bacteria that reside in 90 degree thermal vents. There are some extremophiles that live in water that is almost boiling without suffering denaturation.

Answer 3

"shape" and "nature of proteins" are not what you're asking. some of the previous obviously attempted to answer your question before reading it.

first of all, people, nucleic acids includes RNA, mRNA etc which are not in double helix shape and therefore does not have hydrogen bonds. so rule that answer out. nucleic acids are made of nucleotides (sp?) which are a base and a phosphate group..or two..or three. point is, they're held together by phosphate bonds, not hydrogen bonds, nor magnetism, nor loneliness.

proteins on the other hand are made up of chains of amino acids (amine and carboxyll (sp?) groups, but thats not important). without explaining too much, these chains are held together by peptide bonds.

--useless info regarding stability---
both phosphate bonds and peptide bonds are metastable (don't quote me on that word). which, if i'm using the right term correctly, means that they should've broken apart spontaneously in accordance with the 2nd law of thermodynamics. in fact a molecule of water (listen up fatties- drink water) will break these bonds which is
--useless info regarding stability---
how your metabolic processes are able to yield energy... you know calvin cycle and stuff...

anyway the reason why i bring this up is because you're comparing the bond strength of phosphate bonds and peptide bonds. well i can't give you exact formation energies that each of these bonds retain, but maybe google can. however i can tell you that ATP (adenosine triphosphate, that $$ molecule you learned about in bio) broken into ADP (removing a phosphate) is a very high yielding, efficient energy molecule, which is why god chose it to be used. yes, god did.

anyway, phosphate bond free energy is something like 40 kj/mole (in thermodynamics it'd be deltaG and it'd be a negative value. might want to do some research on that too depending on how important this question is.) so if you get the value of a peptide bond free energy and its less, that would might be a sufficient answer for your teacher. if its not, call him an ***.

oh ps. in thermodynamic chemistry there's an equation that goes deltaG = deltaH (enthalpy) - (temperature in Kelvin x deltaS (entropy)). once you get the enthalpy and entropy values for peptide and phosphate bonds plug them in and set delta G to 0, solve for temperature to determine at what temperature deltaG becomes negative (spontaneous). hope that helps.

Answer 4

Different type of bonding. Furthermore, DNA is so much smaller in nature than protein.

Answer 5

BOTH NUCLEIC ACIDS AND PROTIENS HAVE HYDROPHOBIC INTERACTIONS AND HYDROGEN BONDINGS.HEAT DISRUPTS BOTH .SO BOTH NA'S AND PROTIENS GET DISRUPTED AT HIGH TEMPERATURE .EXCEPT THAT DUE TO CHANGEBLE NATURE OF PROTIENS FOR PERFORMING DIFFERENT FUNCTIONS THIER BONDS ARE PRONE TO CHANGE EASILY.SO THE HEAT EFFECTS THEM EASILY THAT THE HARD UNCHANGEBLE STRUCTURE OF NUCLEIC ACIDS.