Life's Chemistry

Matter

Matter

Anything that takes up space and has mass

Element

Pure substance that cannot be broken down into simpler substances by ordinary chemical or physical means

Atom

Smallest unit of an element

Molecule

Multiple atoms bound together

Atomic Number

Number of Protons

Mass Number

Number of protons and neutrons

Isotope

Atoms with the same number of protons but different number of neutrons

S Orbitals

Electrons in this orbital exist within a hypothetical sphere (2 e- per orbital)

P Orbitals

Electrons in this orbital exist in dumbbells (2e- per dumbbell, 6e- total)

Ionic Bonds

Strongest bonds, hold over the greatest distance

Nonpolar Covalent Bonds

Electrons are shared equally

Polar Covalent Bonds

Electrons are shared unequally

Electronegativity

How badly an atom wants electrons

Hydrophilic

Polar molecules that associate readily with water

Hydrophobic

Polar molecules that are excluded by water and other polar molecules

Hydrogen Bonds

Easier bond to break, weak compared to other bonds

Intermolecular

Forces between molecules

Intramolecular

Forces within molecule

Van der Waals Forces

Develop when slight positive or negative sides are established in nonpolar molecules due to their constant motion (weakest bond)

H2O

POLAR AND SMALL

Water Lattice

H bonds break and reform, molecules can slip by each other

Ice Lattice

Molecules are far apart and uniformly arranged, less dense than liquid water

Cohesion

Because of hydrogen bonds, water molecules “stick” to each other

Adhesion

Water molecules “stick” to surfaces

Surface Tension

Hydrogen bonding makes tension force on surface of water

Acid

Proton Donors (release H+ ions)

Bases

Proton Acceptors (reduce H+ concentration)

Acidity

The concentration of H+ ions compare to OH- ions

Buffers

Can combine with excess H+ or OH= to mediate changes in PH

Neutral Lipids

Stored and used as energy source

Phospholipids

Form cell membranes

Steroids

Serve as hormones that regulate cellular activities