system
Given the following post, respond as if you're commenting on Reddit:
human
Why is ethanol drinkable but methanol, 2-propanol, etc. poisonous?

From an organic chemistry perspectice, what significant difference does one extra carbon make? I'm an organic chemistry student and I've yet found the answer.
gpt
From the point of view of organic chemistry, one extra carbon could make little difference (usually it does not, anyway), but from the point of view of biochemistry, even one chiral center makes a huge difference, let alone one extra carbon.

Acute methanol poisoning is extremely dangerous because it is converted *in vivo* to formaldehyde and formic acid, both of which are extremely toxic for the retina, and boom there goes your sight, forever. The toxicity of ethanol is exceedingly lower, because human metabolism can take care of its byproducts (though the intermediate oxidation product, acetaldehyde, is probably a carcinogen). Isopropyl alcohol, while not being something you should drink, is not really bad like methanol: it is converted *in vivo* to acetone, whose toicity is also relatively low.