Bio Module 1 - Chemistry of Life

basic unit of life

cells

cells are made up of ____________

molecules

proton charge

positive

neutron charge

neutral

electron charge

negative

mass of atom determined by

(number of) protons and electrons

electron cloud

electrons around the nucleus

atoms contain equal # of

protons and electrons

atomic number is determined by the # of _____ and therefore could also determine the _____________

protons, name of element

mass number is determined by the # of

protons and neutrons

electrons orbit the

proton

isotopes are atoms with ______ and therefore have a different ______

different # of neutrons but same # protons, mass number

distribution of electrons determines

element reactivity

octet rule states that

elements are most stable when their outermost energy level (valence shell) has exactly 8 electrons

____ has only one electron shell which can only hold _____ electrons

helium, 2

anions

become negative when gaining electron(s)

cations

become positive when losing electron(s)

molecules are a

group of (same element) atoms

• chemically bonded

compounds are a

group of (different element) atoms

• chemically bonded

Intramolecular forces (in cells)

Covalent + Ionic bonds

Intermolecular forces (between cells)

Hydrogen bonds + Vanderwaals forces

Covalent bond

sharing electrons between two atoms

Ionic bond

“donated” electrons

hydrogen bonds

“magnetic attraction” between hydrogen and another molecule (no electron sharing/donating)

Van der Waals Forces

“magnetic” attraction between positive and negative charges; distance dependent

nonpolar (covalent bond)

equal sharing of electrons

polar (covalent bond)

unequal sharing of electrons

properties of water

• cohesion/adhesion

• high specific heat capacity + heat of vaporization

• solid water floats (water molecules expand in ice)

• transparent (photosynthesis of plants)

• good solvent

cohesion

molecules staying close due to hydrogen bonds

adhesion

clinging of one substance to another (stickiness)

solution

homogenous mixture

eg. salt water

solvent

dissolving agent

eg. water

solute

substance being dissolved

eg. salt

aqueous solution

solution in which water is the solvent

acidic solutions

less than 7 (pH value)

basic solutions

more than 7 (pH value)

Isomers

compounds with same molecular formula but different structures

structural isomer

have different covalent bond arrangement

cis-trans isomer

have different arrangement around a double bond

enantiomers

“left” and “right” handed versions of each other

acids

increase H+ concentration

bases

decrease H+ concentration

buffers

substances that minimize fast changes in pH

hydrocarbons

molecules (like fat) that contain only carbon and hydrogen

• undergo reactions that release large amounts of energy

carbon is good at ______ due to its ____________

forming strong covalent bonds, electron distribution