Chapter 8: Photosynthesis

Photosynthesis

The process by which plants use sunlight to convert carbon dioxide and water into glucose and oxygen.

Endergonic

A chemical reaction that requires energy input to proceed.

Cellular respiration

The process by which cells break down glucose and other organic molecules to release energy.

Anoxygenic photosynthesis

A type of photosynthesis that does not produce oxygen, found in certain bacterial groups.

Oxygenic photosynthesis

A type of photosynthesis that produces oxygen, carried out by cyanobacteria, algae, and land plants.

Chloroplasts

Organelles found in plant cells that are responsible for photosynthesis.

Light-dependent reactions

The reactions in photosynthesis that require sunlight and produce ATP and NADPH.

Carbon fixation reactions

The reactions in photosynthesis that use ATP and NADPH to convert carbon dioxide into organic molecules.

Thylakoid membrane

The internal phospholipid bilayer in chloroplasts that contains chlorophyll and other pigments for capturing light energy.

Photosystems

Clusters of pigments in the thylakoid membrane that capture and transfer light energy to the reaction center.

Chlorophyll

The main pigment involved in photosynthesis, responsible for absorbing light energy.

Carotenoids

Pigments that absorb light energy and act as antioxidants in photosynthesis.

Action spectrum

The range and efficiency of photon absorption by different molecules in photosynthesis.

Antenna complex

A complex of pigments that gather photons and transfer the captured light energy to the reaction center.

Reaction center

The part of a photosystem where photons are gathered and excited electrons are transferred.

Photosystem 1

A photosystem that transfers electrons to NADP+ to produce NADPH.

Photosystem 2

A photosystem that oxidizes water to replace electrons lost in photosystem 1 and generates ATP.

Chemiosmosis

The movement of protons across a membrane to generate ATP.

Calvin Cycle

The series of reactions in photosynthesis that use ATP and NADPH to convert carbon dioxide into organic molecules.

Photorespiration

A process that occurs in plants under certain conditions, leading to the release of carbon dioxide instead of its fixation.

C3 photosynthesis

The type of carbon fixation used by most plants, involving the Calvin cycle and the formation of a 3-carbon acid.

C4 plants

Plants that use a different pathway, involving PEP carboxylase, to fix carbon dioxide and minimize photorespiration.

CAM plants

Plants that use a different pathway, involving temporal separation of carbon fixation and decarboxylation, to minimize photorespiration.

Stomata

Specialized openings in plant leaves that regulate the exchange of gases, including carbon dioxide and oxygen.

Carbon fixation

The process of converting carbon dioxide into organic molecules, such as glucose, during photosynthesis.