CH 2 Water Properties, Bonding, and Macromolecules in Biology

Cohesion

Sticks to itself.

Adhesion

Sticks to other things.

High heat capacity

Holds heat.

High heat of vaporization

Good cooling.

Great solvent

Ability to dissolve many substances.

Hydrogen bonds

Weak bonds between water molecules that give water stickiness, surface tension, and temperature stability.

Atoms

Smallest unit of matter.

Elements

Pure type of atom.

Protons

Positively charged particles.

Neutrons

Neutral particles.

Electrons

Negatively charged particles.

Mass number

Protons + neutrons.

Atomic number

Number of protons.

Ionic bonds

Electrons are given/taken.

Covalent bonds

Electrons are shared.

Valence electrons

Outer electrons that are shared or transferred to form bonds.

Polar molecules

Uneven sharing of electrons (has + and - ends).

Non-polar molecules

Even sharing of electrons (no charge difference).

Isotopes

Atoms of the same element with different number of neutrons (different mass).

Acids

Release H+.

Bases

Take H+.

pH scale

Measures acidity from 0-14.

Buffers

Keep pH steady.

Macromolecules

Large molecules essential for life.

Carbohydrates

Sugars that provide quick energy and cell structure.

Lipids

Fatty acids that provide long-term energy, membranes, and hormones.

Proteins

Amino acids that provide structure, enzymes, and transport.

Nucleic acids

Nucleotides that store genetic information (DNA, RNA).

Dehydration/condensation

Joins macromolecules by removing water.

Hydrolysis

Breaks macromolecules by adding water.

Functional groups

Small atom groups that give molecules special properties.

Amino group

-NH₂ functional group in amino acids.

Carboxyl group

-COOH functional group in amino acids.

Protein structure levels

Primary, Secondary, Tertiary, Quaternary.

Enzymes

Speed up chemical reactions by lowering activation energy.

Denaturation

When a protein loses its shape and stops working.

Hydrophobic

Avoids water (oils).

Hydrophilic

Likes water (sugars).