Question

I'm trying to read ''cell biology and genetics'. Its a good read so far, but however does raise some questions for me:

Carbohydrates have carbon:hydrogen:oxygen in ratio 1:2:1. Does that mean all molecules with these elements in this ratio are carbohydrates? (or is it a subset?)

Is any organic hydrophobic molecule by definition a lipid or are lipids a subset of the group of hydrophobic organic molecules?

Answer 1

you can have hydrophobic amino acid too. Does that mean this hydropohobic amino acid is a lipid? The answer is no. You can say lipid is a subset of hydrophobic group.

Carbohydrates empirical formula is Cm(H2O)n. Let say glucose is C6 H12 O6, maltose is made of 2 glucose. But maltose has the formula of C12 H22 O11 because they loss one water to form one glycosidic bond. Therefore, they don't have 1C:2H:1O ratio. Furthermore, there is an exception. Deoxyribose sugar is C5 H10 O4, which is one oxygen less than ribose.

I hope this helps.

Answer 2

hmm, not very scientific that there doesn't even seems to be a clear definition (genus-differentia style) of carbohydrate. I get the impression the same goes for the lipids. But maybe its not that important...

thanks...