AP Biology Unit 1: Building the Molecules of Life & Chemical Nature of Biology

Vocabulary practice flashcards covering AP Biology Unit 1 lecture notes on functional groups, organic carbon structures, acid-base chemistry, water properties, and general biological chemistry principles.

Hydroxyl Group

A functional group consisting of an $-OH$ group where a hydrogen atom is bonded to an oxygen atom that attaches to the carbon skeleton of an organic molecule, forming compounds known as alcohols.

Carbonyl Group

A functional group consisting of a $-C=O$ group where a carbon atom joins with an oxygen atom through a double bond, forming ketones when within a carbon skeleton or aldehydes when at the end of a chain.

Carboxyl Group

A functional group containing a $-COOH$ group where a carbon atom is bonded to a hydroxyl group and double-bonded to an oxygen atom, characteristic of organic or carboxylic acids.

Amino Group

A functional group containing an $-NH_2$ group attached to a carbon atom, capable of picking up $H^+$ ions from solutions to form basic $NH_3^+$ ions.

Sulfhydryl Group

A functional group containing an $-SH$ group where a carbon atom is bonded to a sulfur atom attached to a hydrogen atom, found in compounds called thiols such as cysteine.

Phosphate Group

A functional group with a $-PO_4$ or $-OPO_3$ structure attached to a carbon skeleton that usually exists as an anion with two negative charges, critical for energy transfer in molecules like ATP.

Resonance

A chemical phenomenon where an electron is delocalized within a molecule and shared across more than one bond, conferring greater molecular stability.

Lewis Structures

Electron dot structures named after chemist Gilbert Louis that represent atoms' chemical symbols surrounded by dots representing valence electrons.

Benzene Ring Structure

A hexagonal ring structure composed of $6$ carbon atoms sharing $6$ delocalized electrons that exhibits high stability due to resonance.

Tetravalency

The state of an atom having $4$ electrons available for bonding in its valence shell, enabling carbon to form four covalent bonds.

Octet Rule

The chemical principle stating that atoms tend to bond in such a way that each atom attains $8$ electrons in its outer valence shell.

Hydrocarbon

An organic compound whose structure consists exclusively of carbon atoms bonded to hydrogen atoms.

Alkane

A class of hydrocarbons that contain exclusively single carbon-carbon bonds, following the general molecular formula $C_n H_{2n+2}$.

Alkene

A class of hydrocarbons containing at least one carbon-carbon double bond, following the general molecular formula $C_n H_{2n}$.

Alkyne

A class of hydrocarbons containing at least one carbon-carbon triple bond, following the general molecular formula $C_n H_{2n-2}$.

Isomers

Compounds that possess identical molecular formulas but differ in their structural formulas and arrangements.

Structural Isomers

Isomers that differ in the covalent arrangement of their carbon skeleton, such as n-butane and isobutane.

Geometric Isomers

Also known as cis-trans isomers, these are compounds with identical covalent bonds that differ in the spatial positioning of functional groups across a double bond.

Arrhenius Concept

An acid-base theory introduced by Svante August Arrhenius explaining acidity and basicity based on a substance's dissociation into ions in water.

Bronsted and Lowry Theory

An acid-base theory stating that an acid acts as an $H^+$ ion donor while a base acts as an $H^+$ ion acceptor.

pH Scale

A logarithmic measure of hydrogen ion concentration introduced by Dr. Soren Sorensen, calculated using the formula $pH = -\text{log}_{10}[H^+]$.

Buffer

An aqueous solution consisting of a weak acid and its conjugate base (such as the carbonic acid-bicarbonate buffer $H_2CO_3 / HCO_3^-$) that resists changes in pH by neutralizing excess $H^+$ or $OH^-$ ions.

Polarity

A molecular property where electric charge is unevenly distributed, creating a slight positive charge on one side and a slight negative charge on the opposite side.

Cohesion

The property of water molecules sticking to one another as a result of polarity and hydrogen bonding.

Adhesion

The property enabling water molecules to stick to or mix with other polar substances.

Biochemistry

The branch of science focused on studying the chemical components and molecular processes occurring within living organisms.

Isotopes

Atoms of the same element that share identical chemical properties but differ in physical properties due to varying numbers of neutrons in their nuclei.

Ionic Bond

A chemical bond formed by the electrostatic attraction between oppositely charged ions known as cations and anions.

Covalent Bond

A strong chemical bond formed when neutral atoms share pairs of valence electrons in their outermost orbitals.

Molarity

A unit of concentration defined as the number of moles of a chemical compound dissolved per liter of water.

Colloid

A mixture where fine particles are evenly dispersed throughout another substance without sedimenting, which scatters light through the Tyndall effect.

Suspension

A mixture containing particles suspended in a liquid that are capable of settling to the bottom over time through sedimentation.