Unit 3 · 3.4 — Photosynthesis [cite: 9, 10, 28]

14 learning items · ~2.8% exam weight (unit share)

Everything to learn here

Concept: Photosynthesis evolved early in Earth's history in primitive prokaryotes, eventually leading to a fully oxygenated atmosphere [cite: 13].
Concept: The Light-Dependent Reactions occur across the thylakoid membrane, utilizing organized photosystems to capture light energy, split water, and generate ATP and NADPH [cite: 13, 14].
Concept: The Calvin Cycle (Light-Independent Reactions) occurs in the stroma, utilizing the ATP and NADPH generated earlier to fix inorganic carbon dioxide into organic sugar molecules [cite: 13, 14].
Vocabulary: Chlorophyll — the primary green pigment molecule embedded in chloroplasts that absorbs optimal wavelengths of light energy [cite: 14].
Vocabulary: Photolysis — the enzymatic splitting of water during the light reactions to provide replacement electrons, releasing oxygen gas as a byproduct [cite: 14].
Lab: Lab Skill: AP Biology Required Investigation — Photosynthesis: Use floating leaf disk assay data to calculate rates of oxygen production and analyze absorption spectra graphs [cite: 6, 14, 35].
Concept: Specific chloroplast structures allow organisms to capture solar energy and store it in chemical bonds.
Concept: Cells use light-dependent pathways to transfer energy into biological molecules for long-term storage.
Equation: $6 C O 2 + 6 H 2 O + l i g h t e n er g y - > C 6 H 12 O 6 + 6 O 2$
Concept: Chloroplasts contain thylakoids for light-dependent reactions and stroma for the carbon-fixing Calvin cycle.
Concept: Electron transport chains move electrons to NADP+, reducing it to NADPH for use in photosynthesis.
Concept: Chlorophyll absorbs light energy to excite electrons, which are replaced by the splitting of water.
Concept: Photosystems I and II are embedded in thylakoid membranes and connected by an electron transport chain.
Concept: Electron transfer through the transport chain establishes a proton gradient across the thylakoid membrane.

Practice problems for this topic are coming — generated and validated by our AI pipeline, aligned to these exact items.