How can something hydrophobic hydrogen bond?

AI Thread Summary
The discussion centers on the properties of nitrogenous bases in DNA, specifically their hydrophobic nature and ability to form hydrogen bonds. While nitrogenous bases are characterized as hydrophobic, they are located on the inside of the DNA double helix, shielded from the aqueous environment. This arrangement allows them to participate in hydrogen bonding despite their hydrophobic characteristics. The conversation also touches on the number of chromosomes in a human somatic cell after the S phase of DNA replication, clarifying that there are 92 chromatids (46 chromosomes, each replicated). The term "hydrophobic bonds" is clarified as a misnomer; instead, the focus is on the hydrophobic nature of the bases and their structural role in DNA, similar to the behavior of amino acids in protein folding.
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1) The nitrogenous bases of DNA hydrogen bond with each other yet they are also characterized as hydrophobic? How can something hydrophobic hydrogen bond?


2) How many chromosomes are present in a human somatic cell after S phase (DNA replication). Is it still 46 or 92?
 
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Where have you read that there are Hydrophobic bonds? In protein structure, I have only heard of Hydrophilic Bonds, where have you got that information from?

It does seem a bit funny that something can be hydrophobic and still not be repelled by a hydrogen bond which is what water consists of. If this is the case, I guess I will have to let someone else takke over from here :smile:
 
There aren't hydrophobic bonds, but the nitrogenous bases are hydrophobic. This is why they are on the inside of the double helix, away from the aqueous environment. My question is: How can the bases be hydrophobic and still have hydrogen bonding?
 
biophysics said:
There aren't hydrophobic bonds, but the nitrogenous bases are hydrophobic. This is why they are on the inside of the double helix, away from the aqueous environment. My question is: How can the bases be hydrophobic and still have hydrogen bonding?

When you're talking about hydrophobic bases, you have to think about the whole molecule and what parts are exposed to the "outside." The hydrophobic part is what is left "sticking out" after the DNA is all assembled. There can still be local hydrogen bonding in other parts of the molecule. You'll get this same concept with amino acids and protein folding.
 
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