Chemistry of Life, Organic Molecules, and Gene Expression

Comprehensive vocabulary flashcards generated from lecture notes covering foundational concepts in general chemistry, organic molecules, macromolecule structures, gene expression, and bioenergetics.

Atom

The fundamental unit of matter composed of subatomic particles: protons, neutrons, and electrons.

Proton

A positively charged subatomic particle located in the atom; its quantity defines the atomic number of an element.

Neutron

A subatomic particle located in the nucleus of an atom that carries no electrical charge.

Electron

A negatively charged subatomic particle orbiting the atomic nucleus.

Element

A pure chemical substance identified specifically by its number of protons (atomic number).

Atomic number

The specific number of protons contained in an atom, which identifies the element.

Ion

An atom or molecule that possesses an uneven number of charged particles (protons and electrons).

Cation

An ion with an overall positive charge, formed when an atom loses negatively charged electrons.

Anion

An ion with an overall negative charge, formed when an atom gains negatively charged electrons.

Ionization

The biological or chemical process in which a neutral atom gains or loses an electron.

Voltage

The separation of charged particles across a space or biological cell membrane.

Current

The flow or movement of charged particles across a space or cell membrane.

Molecule

A structure consisting of multiple individual atoms linked together through chemical bonds.

Chemical bond

An attraction or connection that holds individual atoms together to form a molecule.

Ionic bond

A chemical bond formed by the electrostatic attraction between two oppositely charged ions, such as in table salt ($NaCl$).

Covalent bond

A strong chemical bond formed when two atoms share pairs of electrons.

Polar covalent bond

A covalent bond in which electrons are shared unequally between atoms, creating a small difference in charge.

Nonpolar covalent bond

A covalent bond in which electrons are shared equally between atoms, such as in molecular oxygen ($O_2$).

Hydrogen bond

A weak attraction between neighboring molecules where a partially positive hydrogen region is attracted to a partially negative region of another molecule without sharing electrons.

Organic molecule

A carbon-containing molecule categorized into carbohydrates, lipids, proteins, or nucleic acids.

Monomer

A single molecular unit that links together with others to form a polymer.

Polymer

A complex molecule containing many repeating molecular units called monomers.

Carbohydrate

An organic molecule class that provides cellular fuel, energy storage, and components of glycoproteins and glycolipids on membranes.

Glucose

A carbohydrate monomer that acts as a primary cellular fuel for energy.

Fructose

A specific example of a carbohydrate monomer.

Starch

A plant carbohydrate polymer composed of repeating glucose monomers.

Cellulose

A carbohydrate polymer of glucose monomers found exclusively in plants.

Glycogen

The primary carbohydrate storage polymer made of glucose monomers in animals.

Lipid

A category of organic molecules including triglycerides, phospholipids, and steroids.

Triglyceride

A lipid composed of a glycerol backbone and three fatty acid tails that functions in energy storage and insulation.

Glycerol

A backbone molecule that holds fatty acid chains together in triglycerides and phospholipids.

Fatty acid

A long carbon chain tail found in triglycerides and phospholipids.

Saturated fatty acid

A lipid chain containing only single covalent bonds with as many hydrogen atoms as possible.

Unsaturated fatty acid

A lipid chain containing one or more double or triple covalent bonds with fewer hydrogen atoms.

Phospholipid

A structural membrane lipid consisting of a glycerol backbone, two hydrophobic fatty acid tails, and one hydrophilic phosphate polar head.

Hydrophilic

Water-loving region or property, such as the phosphate-containing polar head group of a phospholipid.

Hydrophobic

Water-fearing region or property, such as the nonpolar fatty acid tails of a lipid.

Steroid

A large lipid molecule defined by a characteristic four-ring carbon structure.

Cholesterol

A membrane steroid molecule from which steroid hormones are synthesized.

Steroid hormone

A chemical messenger synthesized from cholesterol that sends signals from one cell to another, such as estrogen or testosterone.

Protein

A functional organic polymer constructed from amino acid monomers.

Amino acid

The monomer building block of proteins.

Primary structure

The specific sequence or string of amino acids in a protein chain.

Secondary structure

The initial folding pattern formed by the primary string of amino acids.

Tertiary structure

The overall three-dimensional folded shape of a single protein chain.

Quaternary structure

The multi-subunit spatial arrangement of a complex protein assembled from multiple amino acid chains.

Enzyme

A specialized protein that accelerates chemical reactions or breaks down carbohydrates to release usable cellular energy.

Nucleic acid

An organic macromolecule category functioning in biological heredity (DNA) and protein synthesis (RNA).

DNA

A nucleic acid polymer composed of nucleotides that carries genetic instructions for heredity.

RNA

A working single-stranded copy of a gene's nucleotide sequence involved in protein synthesis.

Nucleotide

The monomer unit of nucleic acids, containing nitrogenous bases such as adenine, thymine, guanine, or cytosine.

Gene

A specific sequence of nucleotides arranged along DNA strands containing instructions to synthesize a protein.

Gene expression

The regulated physiological process of converting genetic DNA instructions into active proteins.

Transcription

The gene expression stage that creates a working copy of a gene as an RNA nucleotide sequence from DNA.

Translation

The gene expression stage that reads an RNA nucleotide sequence to place amino acids into the correct primary structure order.

ATP (adenosine triphosphate)

A specialized nucleotide that acts as the primary unit of energy transfer within the body.

ADP (adenosine diphosphate)

The product formed along with free energy release when ATP undergoes hydrolysis.

Hydrolysis

A chemical reaction that splits a compound by adding water, such as breaking ATP down into ADP to release free energy.