DK - AP Biology 10 Essentials Flashcards

Electronegativity

The ability of an atom to attract shared electrons in a chemical bond. Higher electronegativity means a stronger pull on electrons.

Polar vs. Non-Polar

Polar: Electrons are shared unequally, creating slightly positive and negative ends.
Non-polar: Electrons are shared equally, so there are no charged ends.

Hydrogen Bond

A weak attraction between a hydrogen atom and an electronegative atom (usually oxygen, nitrogen, or fluorine) on another molecule. Important in water and DNA.

Ionic Bond

A bond formed when one atom transfers electrons to another, creating oppositely charged ions that attract each other. Usually between a metal and a nonmetal.

Covalent Bond

A bond formed when two atoms share one or more pairs of electrons. Usually occurs between nonmetals.

Hydrophilic

“Water-loving.” A substance that is attracted to water and dissolves or mixes well with it. Usually polar or charged.

Hydrophobic

“Water-fearing.” A substance that repels water and does not dissolve in it. Usually nonpolar.

Ratio

A comparison of two quantities using division. It can be written as a:b, a to b, or a/b.

Proportion

An equation showing that two ratios are equal. Ex: 2/4 = 4/8

Percent Change

The amount a value increases or decreases, expressed as a percentage.

% change = (New Value − Original Value) ÷ Original Value × 100%