BIOL-107 Topic 5: Organic Molecules – Vocabulary Flashcards

32 vocabulary flashcards covering definitions of key terms from the Organic Molecules lecture, including molecule categories, carbon bonding, functional groups, macromolecules, and biochemical reactions.

Molecule

A compound formed by bonding two or more elements together.

Inorganic Molecule

A relatively small, simple compound that usually lacks carbon, does not come from living things, and returns to its native state (e.g., H2O, CO2).

Organic Molecule

A compound containing at least one carbon-hydrogen (C-H) bond; can be synthesized by organisms or in the lab and is irreversibly altered if excessive energy is added or removed.

Carbonic Acid (H2CO3)

Contains carbon and hydrogen but no C-H bond, so it is classified as inorganic.

Valence Electrons of Carbon

Four electrons in the outer shell, allowing carbon to form four covalent bonds.

Covalent Bond

A chemical bond formed when atoms share electrons; typical for carbon.

Single Bond

A covalent bond involving one shared pair of electrons, represented by one stick in diagrams.

Double Bond

Two atoms sharing two pairs of electrons (e.g., C=C), represented by two sticks (=).

Triple Bond

Two atoms sharing three pairs of electrons, common in molecules like acetylene (C2H2).

Hydrocarbon

The simplest carbon compound consisting only of carbon and hydrogen atoms forming chains, branches, or rings.

High-Energy C-H Bond

The covalent bond between carbon and hydrogen that stores significant energy, making hydrocarbons good fuels.

Functional Group

A specific combination of atoms attached to a carbon backbone that confers characteristic chemical properties and reactivity.

Hydroxyl Group (-OH)

Polar functional group that makes molecules alcohols, hydrophilic, and capable of forming hydrogen bonds.

Carboxyl Group (-COOH)

Acidic functional group that donates H⁺, lowers pH, and is found in amino acids and fatty acids.

Amine Group (-NH2)

Basic functional group that accepts H⁺, forms amino acids, and contributes to protein structure.

Phosphate Group (-PO₄²⁻)

Highly charged functional group important in energy transfer molecules (ATP) and nucleic acids (DNA/RNA).

Sulfhydryl Group (-SH)

Functional group containing sulfur that can form disulfide bridges, stabilizing protein structure.

Carbonyl Group – Aldehyde

Carbonyl (C=O) at the end of a carbon chain; characteristic of aldehydes.

Carbonyl Group – Ketone

Carbonyl (C=O) within a carbon chain; characteristic of ketones.

Methyl Group (-CH3)

Non-polar, hydrophobic functional group that can modify DNA and alter molecular activity.

Hydrophilic

Describes molecules or regions that are attracted to water due to polarity or charge.

Hydrophobic

Describes molecules or regions that repel water, usually non-polar, such as long hydrocarbon chains.

Isomer

One of two or more molecules with the same chemical formula but different structural arrangements (e.g., glucose vs. fructose).

Macromolecule

A large organic molecule composed of many smaller units; includes carbohydrates, lipids, proteins, and nucleic acids.

Monomer

A single small subunit that can join with others to form a polymer.

Polymer

A large molecule made of repeating monomer subunits linked by covalent bonds.

Dehydration Synthesis

An energy-requiring reaction that joins monomers by removing an H and an OH (water molecule) to form a covalent bond.

Hydrolysis

The addition of water to break covalent bonds in polymers, splitting them into monomers.

Enzyme

A biological catalyst that speeds up dehydration synthesis and hydrolysis by bringing reactants together.

Carbohydrate

Macromolecule containing C, H, and O in a 1:2:1 ratio; primary energy source (e.g., glucose).

Lipid

Hydrophobic macromolecule with C, H, and relatively few O atoms; includes fats, oils, and steroids.

Protein

Macromolecule composed of amino acid monomers containing C, H, O, N, and sometimes S; performs structural and catalytic roles.

Nucleic Acid

Macromolecule containing C, H, O, N, and P that stores and transmits genetic information (DNA, RNA).