Photosynthesis and Carbon Fixation Summary

This set of flashcards covers core vocabulary and concepts related to photosynthesis, including processes, structures, and mechanisms involved.

Photosynthesis

A process that converts light energy into chemical energy in the form of food.

Chloroplasts

Organelles in eukaryotes where photosynthesis occurs, containing thylakoids.

Thylakoids

Membrane structures inside chloroplasts that are stacked to form grana and involved in light reactions.

Light reactions

The first stage of photosynthesis that converts solar energy into ATP and NADPH.

Calvin cycle

The second stage of photosynthesis, occurring in the stroma, that uses ATP and NADPH to convert CO₂ into sugar.

Photosystem

A complex of proteins and pigments that absorbs light and initiates the process of energy transfer in photosynthesis.

Rubisco

The enzyme that catalyzes the first step in the Calvin cycle, fixing CO₂ into organic molecules.

C3 plants

Plants that fix carbon dioxide through the Calvin cycle, typically under normal conditions.

C4 plants

Plants that minimize photorespiration by fixing CO₂ into four-carbon compounds.

CAM plants

Plants that open their stomata at night to incorporate CO₂ into organic acids to minimize water loss during the day.

Photorespiration

A process that occurs when Rubisco binds O₂ instead of CO₂, wasting energy without producing sugars.

NADPH

An electron carrier produced in the light reactions, used in the Calvin cycle for reducing power.

ATP

A molecule that carries energy within cells, produced during the light reactions and used in the Calvin cycle.

Proton-motive force

The force generated by the electron transport chain that drives ATP synthesis during photosynthesis.

Grana

Stacks of thylakoids within chloroplasts that increase the surface area for light absorption.

Electromagnetic energy

Energy from light, which includes visible wavelengths that drive photosynthesis.