AP Biology Unit 1: Chemistry of Life, Water Properties, and Macromolecules

Comprehensive vocabulary flashcards covering basic chemical concepts, water properties, hydrogen bonding, and biological macromolecules across Topics 1 through 6.

Organic Chemistry

The study of compounds containing covalently bonded carbon.

Organic Compounds

Compounds that contain both carbon and hydrogen.

Hydrocarbons

Organic molecules consisting exclusively of carbon and hydrogen, which serve as a framework for more complex organic molecules.

Functional Groups

Chemical groups attached to a carbon skeleton that participate directly in chemical reactions.

Polymers

Chain-like macromolecules made of similar or identical repeating units covalently bonded together.

Monomers

The repeating molecular units that serve as the building blocks of polymers.

Dehydration Reaction

A reaction that bonds two monomers together with the loss of a water molecule ($\text{A} + \text{B} \rightarrow \text{AB} + \text{H}_2\text{O}$).

Hydrolysis

A reaction that breaks the covalent bonds in a polymer by the addition of a water molecule ($\text{AB} + \text{H}_2\text{O} \rightarrow \text{A} + \text{B}$).

Monosaccharides

Simple sugars with molecular formulas that are multiples of the unit $\text{CH}_2\text{O}$, serving as fuel for cellular respiration and building blocks for polymers.

Disaccharides

Two monosaccharides joined together by covalent bonds, such as sucrose (composed of glucose and fructose).

Polysaccharides

Polymers composed of many sugar monomers linked together via dehydration reactions.

Starch

A storage polysaccharide in plants composed of glucose monomers, allowing plants to store excess glucose.

Glycogen

A storage polysaccharide in animals composed of glucose monomers, stored primarily in liver and muscle cells.

Cellulose

A tough structural polysaccharide that forms the structural walls of plant cells.

Chitin

A structural polysaccharide that forms the exoskeletons of arthropods.

Protein

A functional molecule consisting of one or more polypeptides folded into a specific 3D shape, comprised of $\text{C}$, $\text{H}$, $\text{O}$, $\text{N}$, and $\text{S}$.

Amino Acids

Organic molecules containing an amino group, a carboxyl group, and a variable side chain ($\text{R}$ group).

Peptide Bond

The covalent bond formed between the carboxyl group of one amino acid and the amino group of another via a dehydration reaction.

Polypeptides

Unbranched polymers of amino acids linked together by peptide bonds.

N-terminus

The end of a polypeptide chain that terminates with a free amino group.

C-terminus

The end of a polypeptide chain that terminates with a free carboxyl group.

Primary Structure

The unique linear sequence of amino acids in a polypeptide chain, determined genetic information.

Secondary Structure

Coils and folds in a polypeptide backbone resulting from hydrogen bonding, forming $\beta$ pleated sheets or $\text{alpha}$ helices.

Tertiary Structure

The overall 3D folding pattern of a polypeptide resulting from interactions between amino acid side chains ($\text{R}$ groups).

Quaternary Structure

The structural shape resulting from the association of two or more polypeptide chains in a single protein.

Disulfide Bridges

Covalent bonds formed between the sulfur atoms of two cysteine monomers, reinforcing tertiary protein structure.

Nucleic Acids

Polymers made of nucleotide monomers that store, transmit, and express hereditary information ($\text{DNA}$ and $\text{RNA}$).

Nucleotide

The monomer of nucleic acids, consisting of a nitrogenous base, a five-carbon sugar (pentose), and one or more phosphate groups.

Pyrimidines

Nitrogenous bases consisting of a single 6-membered ring, including cytosine, thymine (in $\text{DNA}$), and uracil (in $\text{RNA}$).

Purines

Nitrogenous bases consisting of a 6-membered ring fused to a 5-membered ring, including adenine and guanine.

Phosphodiester Linkage

The covalent bond that links adjacent nucleotides along a sugar-phosphate backbone in a $\text{5'}$ to $\text{3'}$ direction.

Antiparallel

The arrangement in a $\text{DNA}$ double helix where the two sugar-phosphate backbones run in opposite $\text{5'}$ to $\text{3'}$ directions.

Lipids

A diverse class of hydrophobic, nonpolar molecules that do not form true polymers.

Fats

Molecules constructed from one glycerol and three fatty acid chains joined by ester linkages.

Saturated Fatty Acid

A fatty acid chain with no carbon-carbon double bonds, maximizing the number of attached hydrogen atoms.

Unsaturated Fatty Acid

A fatty acid chain containing one or more double bonds between carbon atoms.

Phospholipids

Molecules with a hydrophilic head and two hydrophobic fatty acid tails that self-assemble into bilayers in water to form cell membranes.

Steroids

Lipids characterized by a carbon skeleton consisting of four fused rings.

Matter

Anything that takes up space and has mass.

Element

A substance that cannot be broken down into other substances by chemical reactions ($92$ occur naturally).

Compound

A substance consisting of two or more different elements combined in a fixed ratio.

Essential Elements

Elements required by an organism to survive and reproduce ($20\text{--}25$% of natural elements, with $\text{C}$, $\text{H}$, $\text{O}$, $\text{P}$, $\text{N}$ making up $96$% of living matter).

Trace Elements

Elements required by an organism in only minute quantities.

Atomic Number

The number of protons contained within the nucleus of an atom.

Atomic Mass

The total mass of an atom, representing the average number of protons plus neutrons across all isotopes.

Groups

Vertical columns on the periodic table containing elements with the same number of valence electrons.

Periods

Horizontal rows on the periodic table containing elements with the same total number of electron shells.

Bohr Model

A structural diagram showing electrons orbiting around an atom's nucleus in discrete energy shells.

Lewis Dot Model

A simplified diagram representing an atom that shows only the electrons present in its valence shell.

Octet Rule

The rule stating that atoms gain, lose, or share electrons to complete their valence shell with $8$ electrons.

Electronegativity

The measure of an atom's ability to attract shared electrons to itself.

Covalent Bond

A chemical bond formed when two nonmetal atoms share one or more pairs of valence electrons.

Nonpolar Covalent Bond

A covalent bond in which valence electrons are shared equally between two atoms.

Polar Covalent Bond

A covalent bond in which electrons are shared unequally due to differences in electronegativity, creating partial electrical charges.

Ionic Bond

A chemical bond resulting from the attraction between oppositely charged ions following the transfer of electrons.

Cation

A positively charged ion formed when an atom loses one or more electrons.

Anion

A negatively charged ion formed when an atom gains one or more electrons.

Hydrogen Bond

An intermolecular bond formed when a partially positive hydrogen atom in a polar molecule is attracted to an electronegative atom in another polar molecule.

Cohesion

The binding attraction between molecules of the same substance, such as hydrogen bonding holding $\text{H}_2\text{O}$ molecules together.

Adhesion

The attraction between molecules of different substances, such as water clinging to plant xylem walls.

Surface Tension

A measure of how difficult it is to stretch or break the surface of a liquid, allowed by cohesive forces in water.

Capillary Action

The upward movement of liquid through narrow spaces caused by cohesion, adhesion, and surface tension (occurring when adhesion is greater than cohesion).

High Specific Heat

The property of water to resist changes in temperature because heat must be absorbed to break hydrogen bonds and released when they form.

Evaporative Cooling

The process where the surface of a liquid cools down during evaporation as molecules with the highest kinetic energy escape as gas.

Solvent

The dissolving agent of a solution.

Solute

The substance that is dissolved in a solution.

Solution

A completely liquid homogeneous mixture of two or more substances.