Botany Notes- Photosynthesis.docx

Photosynthesis

Photosynthesis

The process that drives all ecological processes, converting CO2 and H2O into O2 and sugar using sunlight.

Chloroplasts

Organelles in plant cells responsible for generating food/energy through photosynthesis.

Grana

Dense stacked membrane systems within chloroplasts where light reactions occur.

Stroma

The fluid inside chloroplasts where dark reactions (Calvin cycle) take place.

Rubisco

An enzyme that fixes CO2 into a solid form during the dark reactions of photosynthesis.

C3 Photosynthesis

A type of photosynthesis where the dark reactions produce a 3-carbon sugar product.

Stomata

Small openings on leaves that allow CO2 to enter and water vapor to exit.

Photorespiration

A process where Rubisco consumes O2 and releases CO2, reducing photosynthetic efficiency.

Accessory Pigments

Pigments like carotenoids that capture light wavelengths not absorbed by chlorophyll.

Thylakoids

Membrane-bound structures in chloroplasts where light reactions occur.

Photosystem II

A protein complex in the thylakoid membrane that splits water to generate O2 and ATP.

Photosystem I

A protein complex that uses ATP from Photosystem II to produce NADPH.

Eukaryotes

Organisms with complex cells, including green algae, which are part of the Plantae clade.

Paraphyletic Group

A group that does not include all descendants from a common ancestor, such as green algae.

Synapomorphies of Plantae

Shared characteristics of Plantae, including chlorophyll a & b and starch as a storage product.

Haplontic Life Cycle

A life cycle where the dominant stage is haploid, typical of most green algae.

Diplontic Life Cycle

A life cycle where the dominant stage is diploid, typical of animals.

Alternation of Generations

A unique plant life cycle involving both multicellular sporophyte (diploid) and gametophyte (haploid) stages.

Pyrenoid

A structure in green algae that helps concentrate CO2 for photosynthesis.

Volvox

A type of green algae that forms colonies and can sense light with an eyespot.