Chapter 2, Pt. 2: The Chemical Basis of Life — Vocabulary Flashcards

Vocabulary flashcards covering key terms from the lecture notes on the chemical basis of life (ATP, acids/bases, pH, carbohydrates, lipids, nucleic acids, proteins, enzymes, and related concepts).

ATP

Adenosine triphosphate; the energy molecule that stores energy in high‑energy phosphate bonds and is regenerated from ADP + Pi via dehydration synthesis.

ADP

Adenosine diphosphate; product of ATP hydrolysis; can be rephosphorylated to form ATP.

Pi (inorganic phosphate)

Phosphate group involved in energy transfer; combines with ADP to form ATP.

pH

A measure of hydrogen ion concentration; normal blood pH is ~7.35–7.45; logarithmic scale.

Buffers

Substances that stabilize pH by accepting or releasing H+ to maintain homeostasis.

Acid

A substance that donates H+ (proton donor); pH < 7.

Base

A substance that accepts H+ (proton acceptor); pH > 7.

Hydrolysis

A reaction that uses water to break chemical bonds.

Dehydration synthesis

A condensation reaction that forms bonds by removing a water molecule.

Anabolism

Metabolic processes that build larger molecules; energy is stored in the process.

Catabolism

Metabolic processes that break down molecules; energy is released.

Inorganic compounds

Small, usually carbon-hydrogen-free molecules (e.g., H2O, CO2, O2).

Organic compounds

Compounds that contain carbon-hydrogen bonds; large and complex (e.g., glucose); CO2 is an exception.

Carbohydrates

Organic compounds with C:H:O in ~1:2:1; energy source; includes monosaccharides, disaccharides, and polysaccharides.

Monosaccharides

Simple sugars; primary energy source; glucose is the most important example; also includes fructose and galactose.

Disaccharides

Two monosaccharides linked by dehydration synthesis (e.g., sucrose, maltose, lactose).

Polysaccharides

Many monosaccharides linked together (e.g., starch, glycogen); energy storage and structural roles.

Glucose

A key monosaccharide; main energy source for the body; highly soluble in water.

Lipids

Hydrophobic organic molecules with a C:H ratio ~1:2; includes fats, oils, and waxes; major energy source and cellular components.

Fatty acids

Long hydrocarbon chains with a terminal carboxyl group; amphipathic; saturated vs. unsaturated.

Saturated fatty acids

Fatty acids with no double bonds; straight chains, pack tightly, associated with artery buildup.

Unsaturated fatty acids

Fatty acids with one or more double bonds; bends in the chain; healthier dietary profile.

Fats (triglycerides)

Glycerol bound to three fatty acids; major energy storage form; also provides insulation and protection.

Steroids

Lipids with four fused carbon rings (e.g., cholesterol, bile salts, Vitamin D); cholesterol is a membrane component and hormone precursor.

Phospholipids

Lipids with glycerol, two fatty acids, and a phosphate-containing head; amphipathic; main membrane component.

Cholesterol

Steroid lipid essential for membranes and hormone synthesis; high blood cholesterol linked to heart disease.

Nucleic acids

Large organic molecules (DNA and RNA) that store and process genetic information; built from nucleotides.

DNA

Deoxyribonucleic acid; double helix with deoxyribose; bases A, G, C, T; base pairing A–T and G–C; stores genetic information.

RNA

Ribonucleic acid; single strand with ribose; bases A, G, C, U; Uracil replaces thymine; directs protein synthesis.

Amino acids

Building blocks of proteins; 20 different types; each has an amino group, a carboxyl group, a unique side chain (R).

Peptide bond

Covalent bond formed between the carboxyl group of one amino acid and the amino group of another during dehydration synthesis.

Protein

Organic molecule made of amino acids; performs diverse roles (structure, transport, enzymes, defense, etc.).

Enzymes

Proteins that act as catalysts to accelerate chemical reactions by lowering activation energy; reusable.

Active site

Region of an enzyme where substrates bind to form the enzyme–substrate complex.

Enzyme-substrate complex

Temporary complex formed when a substrate binds to an enzyme's active site, leading to product formation.

Primary structure

Linear sequence of amino acids in a polypeptide.

Secondary structure

Local folding of the polypeptide into alpha helices or beta sheets via hydrogen bonds.

Denaturation

Loss of protein structure due to changes in temperature, pH, or ionic conditions; often alters function.