Botany | Photosynthetic Prokaryotes | Dr. Sara Browning | PBA Fall 2024

Green and Purple Bacteria

Sulfur bacteria studied by Van Neil led to his generalized photosynthesis equation

Halobacterium

•Tolerates high salt

Bacteriorhodopsin

Pigmented protein found in abundance in the plasma membrane of the salt-loving archaeon Halobacterium halobium; pumps protons out of the cell in response to light.

Cyanobacteria

"Blue-green algae"

Cyanobacteria

Characteristics

- Tiny prokaryotic cells often with slimy sheath

- Unicellular or filamentous

- Phycobilins- phycocyanin and phycoerythrin; Chl a

- Evolved oxygenic photosynthesis

- Dominant life form for ~ 85% of Earth's history

Eutrophication

A process by which nutrients, particularly phosphorus and nitrogen, become highly concentrated in a body of water, leading to increased growth of organisms such as algae or cyanobacteria.

Nitrogen Fixation in Heterocysts

Prochlorophytes

Cyanobacteria? chlorophyll a, b; carotenoids; no phycobilins

Prochlorococcus

Most numerous photosynthetic organism

Tiny side and genome

40-50% of biomass of marine phytoplankton!

Extremely important global O2 producers