Chemistry of Life & Biomolecules – Key Vocabulary

Vocabulary flashcards covering fundamental chemistry, inorganic & organic molecules, metabolic processes, and related health conditions from Chapters 3 and 4 lecture notes.

Element

A pure substance that cannot be broken down by ordinary chemical methods; major ones in the body are H, C, O, and N.

Trace Element

An element required by the body in very small amounts for proper physiological function.

Atom

Smallest unit of an element, composed of protons, neutrons, and electrons.

Proton

Positively charged sub-atomic particle found in the nucleus of an atom.

Neutron

Uncharged sub-atomic particle located in the atomic nucleus.

Electron

Negatively charged sub-atomic particle that orbits the nucleus and participates in chemical reactions.

Atomic Number

The number of protons in an atom’s nucleus; defines the element.

Mass Number

The total number of protons plus neutrons in an atom’s nucleus.

Molecule

Two or more atoms chemically bonded together (e.g., O₂).

Compound

A substance composed of atoms of two or more different elements chemically combined (e.g., CO₂).

Chemical Bond

Force that holds atoms together; includes ionic, covalent, and hydrogen bonds.

Ionic Bond

Chemical bond formed by the transfer of electrons, producing oppositely charged ions that attract each other (e.g., NaCl).

Ion

An atom or molecule with a net electric charge due to loss or gain of electrons.

Covalent Bond

Chemical bond created by the sharing of one or more pairs of electrons between atoms.

Hydrogen Bond

Weak attraction between a slightly positive hydrogen in one polar molecule and a slightly negative atom in another; important in water and biomolecules.

Polar Molecule

A molecule with an unequal distribution of charge, resulting in positive and negative ends (e.g., H₂O).

Nonpolar Molecule

A molecule with an even distribution of electrical charge, lacking distinct poles.

Synthesis Reaction

Chemical reaction that builds larger molecules from smaller ones (A + B → AB); synonymous with anabolism.

Decomposition Reaction

Chemical reaction that breaks a molecule into smaller parts (AB → A + B); synonymous with catabolism.

Exchange Reaction

Chemical reaction in which parts of two molecules are exchanged, forming two new compounds (AB + CD → AD + CB).

Metabolism

Sum of all chemical reactions in the body, encompassing catabolism and anabolism.

Catabolism

Metabolic processes that break down molecules and release energy (often via hydrolysis).

Anabolism

Metabolic processes that synthesize complex molecules from simpler ones, requiring energy.

Inorganic Compound

Substance that generally lacks C-C or C-H bonds; includes water, oxygen, carbon dioxide, and electrolytes.

Water (H₂O)

Most abundant inorganic molecule; excellent solvent, temperature buffer, transport medium, and participant in reactions.

Oxygen (O₂)

Molecule required for cellular respiration and energy release via decomposition reactions.

Carbon Dioxide (CO₂)

Waste product of metabolism; influences body pH balance.

Electrolyte

Substance that dissociates in water to form ions, enabling conduction of electricity; includes acids, bases, salts.

pH

Measure of hydrogen ion concentration; 7 is neutral,

Acid

Substance that donates H⁺ ions in solution, lowering pH.

Base

Substance that accepts H⁺ ions or releases OH⁻, raising pH.

Salt

Compound formed from an acid and base reaction, yielding ions other than H⁺ or OH⁻ in solution.

Organic Molecule

Compound containing carbon-carbon or carbon-hydrogen bonds; includes carbohydrates, lipids, proteins, nucleic acids.

Carbohydrate

Organic molecule that serves as primary energy source; classified as monosaccharides, disaccharides, or polysaccharides.

Monosaccharide

Simple sugar, single carbohydrate unit; example: glucose.

Disaccharide

Carbohydrate composed of two monosaccharides linked together; example: sucrose.

Polysaccharide

Complex carbohydrate of many monosaccharides; example: glycogen.

Lipid

Hydrophobic organic compound used for energy storage, membrane structure, insulation, and hormone synthesis.

Triglyceride

Most abundant lipid; glycerol plus three fatty acids, major energy reserve.

Saturated Fatty Acid

Fatty acid with no double bonds; solid at room temperature; raises LDL cholesterol.

Unsaturated Fatty Acid

Fatty acid with one or more double bonds; liquid at room temperature (oils).

Phospholipid

Lipid with phosphate group; has hydrophilic head and hydrophobic tails, forming cell membrane bilayers.

Steroid

Lipid with four fused carbon rings; includes cholesterol and steroid hormones.

Prostaglandin

Lipid derivative produced by cell membranes; acts as local messenger influencing hormones, blood pressure, and inflammation.

Protein

Most abundant organic compound; composed of amino acids; performs structural and functional roles.

Amino Acid

Building block of proteins; 21 standard types, 9 essential in diet.

Essential Amino Acid

Amino acid that cannot be synthesized by the body and must be obtained from food.

Nonessential Amino Acid

Amino acid the body can synthesize internally.

DNA (Deoxyribonucleic Acid)

Double-helix nucleic acid storing genetic instructions; bases A-T and C-G.

RNA (Ribonucleic Acid)

Single-stranded nucleic acid involved in protein synthesis and gene regulation; contains ribose sugar.

ATP (Adenosine Triphosphate)

Primary energy currency of cells; releases energy when phosphate bonds are broken.

NAD⁺ / FAD

Coenzymes that transfer energy and electrons during cellular respiration.

cAMP (Cyclic AMP)

Nucleotide that acts as an intracellular second messenger in signaling pathways.

Diabetes Mellitus

Disease involving carbohydrate metabolism characterized by high blood glucose and insulin problems.

Hyperlipidemia

Disorder of elevated lipid levels in blood, increasing cardiovascular risk.

Phenylketonuria (PKU)

Genetic disorder affecting protein metabolism due to deficiency of phenylalanine hydroxylase.

Genetic Condition

Disease caused by abnormalities in nucleic acids (DNA mutations or chromosomal issues).