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

Biological systems are governed by chemical principles. ATP is the cell's main energy currency, synthesized from ADP + Pi using energy from food (dehydration synthesis) and broken down to release energy (hydrolysis). Anabolism traps energy, while catabolism releases it.

pH balance is critical; normal blood pH is 7.35\leq \text{pH} \leq 7.45, maintained by buffers that stabilize pH by accepting or donating H+. The pH scale is logarithmic.

Inorganic compounds are small and often lack C and H together (e.g., \mathrm{H2O}, CO2). Organic compounds are large, complex molecules containing C and H (e.g., glucose, \mathrm{C6H{12}O_6}), including carbohydrates, lipids, nucleic acids, and proteins.

Carbohydrates (\text{C:H:O} \approx 1:2:1) provide short-term energy and include monosaccharides (glucose), disaccharides, and polysaccharides (starch, glycogen).

Lipids (low O content) serve for energy storage, insulation, and membrane structure. Types include fatty acids (saturated/unsaturated), triglycerides (fats), steroids (cholesterol), and phospholipids (amphipathic, in cell membranes).

Proteins, built from 20 amino acids joined by peptide bonds, perform diverse functions: support, movement, transport, buffering, metabolic regulation (enzymes), coordination, and defense. Their function relies on their complex primary, secondary, tertiary, and sometimes quaternary structures; denaturation alters function.

Enzymes are essential proteins that catalyze specific reactions by lowering activation energy via active site binding, and they are reusable.

Nucleic acids (DNA and RNA) store and process genetic information. They are composed of nucleotides (sugar, phosphate, nitrogenous base). DNA is a double helix with deoxyribose and bases A, G, C, T (A-T, G-C pairing), storing genetic instructions. RNA is single-stranded with ribose and bases A, G, C, U, carrying out protein synthesis directed by DNA.

High-energy compounds like ATP are central to cellular work, storing and transferring energy via phosphate bonds.