AP Biology Unit 1: Chemistry of Life Flashcards

Vocabulary flashcard set for AP Biology Unit 1: Chemistry of Life, covering water properties, biological macromolecules, nucleic acids, and protein folding.

Polar Covalent Bond

A type of covalent bond formed when electrons are shared unequally between atoms due to differences in electronegativity, creating partial positive and partial negative charges.

Hydrogen Bond

An attraction between the partial negative charge on the oxygen atom of one polar water molecule and the partial positive charge on the hydrogen atom of another water molecule.

Cohesion

The phenomenon where hydrogen bonds hold water molecules together, creating surface tension and assisting in water transport against gravity in plants.

Adhesion

The attraction between different substances, such as water molecules bonding to plant cell walls to counter the pull of gravity.

Specific Heat

The amount of heat that must be absorbed or lost for $1\,\text{g}$ of a substance to change its temperature by $1^\circ\text{C}$.

Hydrophilic

Describing polar or ionic substances that have an affinity for water and dissolve readily in aqueous solutions.

Hydrophobic

Describing nonpolar substances that lack an affinity for water and do not dissolve in aqueous solutions.

Hydronium Ion ($\text{H}_3\text{O}^+$)

A water molecule with an extra proton, formed when a hydrogen ion ($\text{H}^+$) binds to a water molecule.

Hydroxide Ion ($\text{OH}^-$)

A water molecule that has lost a proton, carrying a net negative charge.

Polymer

A long macromolecule consisting of many similar or identical building blocks linked by covalent bonds.

Monomer

A small repeating chemical unit that serves as the essential building block for polymers.

Dehydration Synthesis

A chemical process that links monomers into polymers by forming a covalent bond while releasing a water molecule as a byproduct.

Hydrolysis

A chemical process that cleaves the covalent bond between monomers in a polymer by adding a water molecule.

Monosaccharide

The simplest carbohydrate monomer, with molecular formulas typically being multiples of $\text{CH}_2\text{O}$, which forms ring structures in aqueous solutions.

Polysaccharide

A carbohydrate macromolecule composed of many monosaccharide building blocks joined by covalent linkages.

Starch

A storage polysaccharide found in plants, consisting entirely of glucose monomers linked by alpha-linkages.

Glycogen

An extensively branched storage polysaccharide made of glucose monomers, stored in animal liver and muscle cells.

Cellulose

A rigid structural polysaccharide composed of glucose monomers connected by beta-linkages that forms plant cell walls.

Saturated Fatty Acid

A fatty acid with straight carbon chains containing only single carbon-to-carbon bonds, maximizing hydrogen atoms and remaining solid at room temperature.

Unsaturated Fatty Acid

A fatty acid containing one or more double carbon-to-carbon bonds that create a kink in the carbon chain, preventing tight packing and making it liquid at room temperature.

Phospholipid

An amphipathic lipid consisting of a glycerol attached to two hydrophobic fatty acid tails and a hydrophilic phosphate group.

Amphipathic

Having both a hydrophilic (polar) region and a hydrophobic (nonpolar) region on the same molecule.

Steroid

A class of lipids defined by a carbon skeleton made of four fused rings, such as cholesterol.

Nucleotide

The monomer of nucleic acids, consisting of a $5$-carbon sugar, a phosphate group, and a nitrogenous base.

Antiparallel

The structural arrangement of a DNA double helix where the two sugar-phosphate strands run in opposite $5'$ to $3'$ directions relative to each other.

Peptide Bond

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

R-group

The variable side chain attached to the central carbon of an amino acid that determines its unique chemical properties (hydrophobic, hydrophilic, acidic, or basic).

Primary Structure

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

Secondary Structure

Coils and folds in a polypeptide backbone, such as alpha-helices and beta-pleated sheets, resulting from hydrogen bonding between backbone atoms.

Tertiary Structure

The overall three-dimensional shape of a polypeptide driven by interactions between amino acid R-groups.

Quaternary Structure

The structural level resulting from the association of two or more distinct polypeptide subunits into one functional macromolecule.

Denaturation

The process by which a protein loses its native three-dimensional conformation and biological activity due to environmental disruptions such as extreme pH or temperature.