AP Bio Unit 1: Chapter 2 - 4

Matter

Anything that takes up space or mass

Element

A substance that cannot be broken down into any other substances through chemical reactions

Compound

A substance made up of two or more chemical substances that are chemically bonded

Make up 96% of living matter

C, H, O, N

Atoms

Smallest units of elements that contain the properties of an element

Protons

Positively charged particles in the nuclues of an atom, determine what element and atom is

Neutron

an elementary particle with 0 charge and mass about equal to a proton; in the atomic nucleus

Electrons

Negatively charged particles that rotate around nuclues in elctron cloud. Thier movement determines atom properties

Isotopes

Atoms with the same number of protons but different number or nuetrons

Chemical bonds

Interactions between valence elctrons in different atoms

Molecule

the simplest structural unit of an element or compound, when different atoms are held together by chemical bonds

Covalent bonds

Bonds in which atoms share valence electrons to both complete thier outer shells

Polar covalent bonds

Covalent bond in which one atom's greater electronegativity allows it to control the orbit of a shared elctron more often. Creates - and + charged poles in molecule

Nonpolar covalent bonds

Covalent bond in which both atoms have a similar electronegativity and equally share the orbit of shared elctrons

Ionic bond

Bond where one atom's electronegativity is great enough to completly take an eltron from another atom. As a result, the atoms are bonded.

Hydrogen bonds

Weak bonds that form between positively charged hydrogen atoms and negatively charged oxygen or nitrogen atoms of another molecule

Van der waals interactions

Weak, constantly forming and breaking bonds that are caused by slight charges due to electron distribution

Chemical reaction

a process in which one or more substances are changed into others
reactants -> products
number of atoms should be the same on each side

Characteristics of water structure

- Polar molecules
- Hydrogen bonding, each molecule can form 4 at a time
- Cohesion
- Adhesion
- Less dense as solid than as liquid

Cohesion

Linking of like molecules, creates surface tension

Adhesion

Clinging of one substance to another substance

Specific heat

the heat required to raise the temperature of one gram of a substance one degree celcius

Solvent

a liquid substance capable of dissolving other substances

Solute

the dissolved matter in a solution; the component of a solution that changes its state

Solution

a homogeneous mixture of two or more substances; frequently a liquid solution

Hydrophillic

Attracted to water, any polar molecules will be hydrophillic

Hydrophobic

Repels water, typically nonpolar molecules

the pH scale

Concentration of H+ vs OH-

Acids

Have exess of H+ ions and pH below 7.0
H+ > OH-

Bases

Have an exess of OH- ions and pH above 7.0

Pure water pH

7.0, true nuetral

Buffers

Substances that minimize changes in pH, provide and take away H+

Carbonic Acid (H2CO3)

Important buffer in living systems

Major elements for life

C, H, O, N, S, P

What do all organic compounds contain?

Carbon

Why is carbon so capable of forming complex molecules?

- 4 Valence e-
- Can form up to 4 covalent bonds
- Can create chains, ring-shaped, and branched molecules

Isomers

Molecules with the same formula but different arrangement of atoms

Functional groups

Chains of atoms attatched to a carbon skeleton