II. THE PROKARYOTIC CELL: BACTERIA
B. PROKARYOTIC CELL ANATOMY
3. Cellular Components Located Within the Cytoplasm
f. Inclusion Bodies and Organelles Used for Photosynthesis
Fundamental Statements for this Learning Object:
1.Oxygenic photosynthesis uses water as an electron donor and generates oxygen during photosynthesis.
2.The cyanobacteria carry out oxygenic photosynthesis.
3. Anoxygenic photosynthesis uses reduced molecules such as H2, H2S, S, and organic molecules as an electron source and generates ATP, NADH and NADPH.
4. The green bacteria and the purple bacteria carry out anoxygenic photosynthesis.
5. Various inclusion bodies are found in certain bacteria that carry out different specialized functions.
LEARNING OBJECTIVES FOR THIS SECTION
In this section on Prokaryotic Cell
Anatomy we are looking at the various anatomical parts that make up
a bacterium. As mentioned in the introduction to this section, a typical bacterium
usually consists of:
We will now look at inclusion bodies and organelles used for photosynthesis.
A. Organelles Used in Bacterial Photosynthesis
There are several major groups of photosynthetic bacteria: cyanobacteria, purple bacteria, green sulfur bacteria, green nonsulfur bacteria, heliobacteria, and acidobacteria. Comparing the cyanobacteria, the purple bacteria, and the green bacteria:
The cyanobacteria carry out oxygenic photosynthesis, that is, they use water as an electron donor and generate oxygen during photosynthesis. The photosynthetic system is located in an extensive thylakoid membrane system that is lined with particles called phycobilisomes that contain light-harvesting phycobiliproteins.
The green bacteria carry out anoxygenic photosynthesis. They use reduced molecules such as H2, H2S, S, and organic molecules as an electron source and generate ATP, NADH and NADPH. The photosynthetic system is located in ellipsoidal vesicles called chlorosomes that are independent of the cytoplasmic membrane.
The purple bacteria carry out anoxygenic photosynthesis. They use reduced molecules such as H2, H2S, S, and organic molecules as an electron source and generate ATP, NADH and NADPH. The photosynthetic system is located in spherical vesicles called chromatophores or lamellar membrane systems that are continuous with the cytoplasmic membrane.
B. Other Inclusion Bodies
- Cyanobacteria contain large inclusion bodies called cyanophycin granules that store nitrogen for the bacteria.
- Cyanobacteria, thiobacilli, and nitrifying bacteria, organisms that reduce CO2 in order to produce carbohydrates, possess carboxysomes containing an enzyme used for CO2 fixation.
- Purple and green photosynthetic bacteria, cyanobacteria, as well as some other aquatic bacteria contain gas vacuoles. These are aggregates of hollow protein cylinders called gas vesicles that are permeable to atmospheric gas, enabling the organism to regulate buoyancy.
- Some bacteria produce inorganic inclusion bodies in their cytoplasm, including volutin granules that store phosphate, and sulfur granules that store sulfur.
- Some bacteria produce organic inclusion bodies containing either polyhydroxybutyrate granules or glycogen granules as an energy reserve.
- Some motile aquatic bacteria are able to orient themselves by responding to the magnetic fields of the earth because they possess magnetosomes, membrane-bound crystals of magnetite or other iron-containing substances that function as tiny magnets.
Gary E. Kaiser, Ph.D.
Professor of Microbiology
The Community College of Baltimore County, Catonsville Campus
This work is licensed under a Creative Commons Attribution 4.0 International License.
Based on a work The Grapes of Staph at https://cwoer.ccbcmd.edu/science/microbiology/index_gos.html.
Last updated: August, 2018
Please send comments and inquiries to Dr.
Gary Kaiser