Polar vs Nonpolar molecules

Question

Can you help me understand the difference between polar and nonpolar molecules?

Answer 1

In regard to Biology:

Polar molecules have a charge and are hydrophiilic, meaning they are attracted to water. Examples of Polar molecules include water and glucose.

Nonpolar molecules do not have a charge and are hydrophobic, meaning they repel water. Examples of nonpolar molecules are lipids.

Answer 2

Polar and non polar molecules are all about the distribution of electrons. To use Feynman's technique to describe it, if electrons was a commodity a molecule where atoms have a non-polar bond would share that commodity, while the molecule with a polar bond will hog the majority of the commodity.

Answer 3

Hi! This question actually has its basis in chemistry, although of course it is hugely important to biology. Nonpolar molecules are molecules where the atoms within them don't have a significant difference in how much they pull electrons (or the pull is symmetrical). That means the electrons are orbiting pretty evenly around all the atoms in the molecule, which means they're very stable.

Polar molecules are the opposite, such as water. In water, the oxygen has a much stronger pull on the electrons than the hydrogen, so the electrons will spend more time closer to the oxygen. Because that means the molecule is basically unbalanced, with more of the electrons' charge on one side (making it negative), that molecule will be more drawn to other molecules that have a negative and positive (because these attract).

However, the nonpolar molecules are very stable on their own, so they are not pulled towards those negative and positive areas, and instead stay closer to other stable molecules that are neutral.

This is why nonpolar molecules don't mix well with polar ones, such as oil (nonpolar) and water (polar) not mixing well!

I am happy to answer any further questions, as your question was quite broad. For example if you're wondering about a specific context or have further details you'd like to know, let me know!