APES Foundational Biology & Chemistry: Key Concepts and Formulas

Organic

Contains carbon AND hydrogen (often with oxygen, nitrogen, phosphorus, sulfur). Originates from living things or biological processes. Examples: Glucose (C₆H₁₂O₆), methane (CH₄), proteins, DNA, fats.

Inorganic

Usually does not contain both carbon and hydrogen together. Includes minerals, salts, and many acids/bases. Examples: Water (H₂O), carbon dioxide (CO₂), nitrate (NO₃⁻), phosphate (PO₄³⁻).

Biotic

Living or once-living components of an ecosystem. Examples: Plants, animals, fungi, bacteria, dead leaves.

Abiotic

Non-living physical and chemical components. Examples: Sunlight, temperature, water, minerals, pH.

Organisms

Living entities made up of cells (e.g., humans, oak trees, bacteria).

Molecules

Chemical structures made of atoms (e.g., CO₂, C₆H₁₂O₆, H₂O).

Photosynthesis

Equation: 6CO₂ + 6H₂O + sunlight → C₆H₁₂O₆ + 6O₂. Reactants: Carbon dioxide, water, sunlight. Products: Glucose, oxygen. Purpose: Converts solar energy into chemical energy stored in glucose.

Cellular Respiration

Equation: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energy (ATP). Reactants: Glucose, oxygen. Products: Carbon dioxide, water, ATP. Purpose: Releases energy stored in glucose for cell work.

Decomposition

Aerobic: Requires oxygen, produces CO₂ and water. Faster process. Anaerobic: Occurs without oxygen, produces methane (CH₄) or other compounds. Slower.

Heterotrophs

Need organic molecules (must eat other organisms). Examples: Humans, lions, fungi.

Autotrophs

Make their own organic molecules from inorganic sources. Examples: Plants, algae, some bacteria.

Enzymes

Proteins that speed up chemical reactions (biological catalysts). If denatured (by heat, pH changes, chemicals), they lose shape and cannot function.

Macromolecules of Life

Proteins: Amino acids, Structure, enzymes, transport, Example: Hemoglobin, keratin. Carbohydrates: Monosaccharides, Energy storage, structure, Example: Glucose, starch. Lipids: Glycerol + fatty acids, Long-term energy, membranes, hormones, Example: Fats, oils, phospholipids. Nucleic acids: Nucleotides, Genetic info, Example: DNA, RNA.

Atom

Smallest unit of an element (Carbon = C, Nitrogen = N).

Molecule

Atoms bonded together (CO₂, NH₃, C₆H₁₂O₆).

Important Chemical Formulas

Carbon dioxide: CO₂. Glucose: C₆H₁₂O₆. Methane: CH₄. Nitrogen gas: N₂. Nitrate: NO₃⁻. Phosphate: PO₄³⁻. Oxygen gas: O₂. Nitric acid: HNO₃. Sulfuric acid: H₂SO₄. Carbonic acid: H₂CO₃.

pH Scale

Acid: pH < 7 (e.g., HNO₃, H₂SO₄, H₂CO₃). Base: pH > 7 (e.g., NaOH). Neutral: pH = 7 (water).

Natural Selection

Variation: Differences between individuals. Adaptation: Traits that improve survival/reproduction. Drives speciation (new species) and extinction (loss of species). Acts on individuals, but populations evolve over time.

Independent Variable (IV)

What you change.

Dependent Variable (DV)

What you measure.

Control Group

Standard for comparison.

Hypothesis

Testable prediction (If...then...).

Averages

Mean = (sum of values) ÷ (number of values).

Percent Change

((new - old) ÷ old) × 100.

Graphs

X-axis = IV, Y-axis = DV. Title should describe relationship (e.g., "Effect of pH on Enzyme Activity").