Why are cyanobacteria different from the majority of bacteria

Photosynthetic Pigments. Photosynthetic Pigments are bacteriochlorophyll. Photosynthetic Pigments is chlorophyll a. Accessory pigments. Accessory pigments like phycocyanin and phycoerythrin are present in dominating form. Reserve food. Cyanophycean starch. Hydrogen donor. During photosynthesis hydrogen donor is not water; as a result oxygen is not evolved.

Cyanobacteria have a characteristic blue-green colour due to its unique pigments. They are referred as blue-green algae too. Some bacteria are able to photosynthesize. But most of the bacteria are heterotrophs. Cyanobacteria are capable of photosynthesizing. The key difference between bacteria and cyanobacteria is that bacteria do not produce free oxygen during their photosynthesis while cyanobacteria are capable of producing free oxygen during the photosynthesis.

Overview and Key Difference 2. What is Bacteria 3. What is Cyanobacteria 4. Similarities Between Bacteria and Cyanobacteria 5. Bacteria are the most abundant microorganisms present in nature.

They are distributed in everywhere. Hence they are known as ubiquitous organisms. Bacteria belong to the prokaryotic group. They do not possess a nucleus and the membrane-bound true organelles such as mitochondria , Golgi bodies, ER etc. Bacteria are unicellular and contain a simple cell structure.

They may be found in a single cell or as colonies. Bacteria have a cell wall that has bacterial specific peptidoglycan layer. Bacteria possess flagella for the locomotion. They multiply by the binary fission. Binary fission is a mode of asexual reproduction.

Conjugation , transformation and transduction are sexual reproductive methods used by bacteria to increase the cell number. Bacteria can have several shapes; coccus, Bacillus, spirillum, etc. The genes coding for photosynthetic pathways seem homologous, but the lineages bearing them are not closely related enough for a common ancestor to have passed the pathways on to all of them.

What's the explanation for this apparent paradox? Horizontal transfer. Humans and most multi-cellular organisms are mainly limited to transferring genetic material vertically — that is, from parent to offspring. However, among many single-celled organisms, horizontal transfer — sharing genetic material directly with another, coexisting member of your own or another species — is commonplace. The new genetic material may then be incorporated into the recipient's genome and passed on to its offspring.

This process is part of what allows microorganisms to evolve so quickly today — for example, in the rapid evolution of resistance to new antibiotics.

Scientists think that horizontal transfer also occurred frequently during the early evolution of life and explains why so many distantly related bacterial lineages can photosynthesize: the genes coding for these processes were passed directly from lineage to lineage, and when the genes were successfully picked up, incorporated into a lineage's genome, and deployed, that lineage was likely favored by natural selection.

Being able to get energy from the sun probably offered a significant survival advantage! So it seems that the basic chemical pathways for capturing energy from the sun evolved in some bacterial lineage several billion years ago scientists still aren't sure in which lineage and the genes encoding these processes were picked up by one lineage of Cyanobacteria.

Then, through the processes of random mutation and natural selection, that lineage eventually evolved a version of the pathway that produces oxygen. This lineage, the ancestor of modern oxygen-producing Cyanobacteria, was so successful that its waste product oxygen eventually transformed the atmosphere into the breathable one that we depend upon today. Once Earth's atmosphere was full of oxygen, the stage was set for the evolution of aerobic respiration — the process that uses oxygen to convert food into usable energy.

The sets of genes responsible for this metabolic pathway were also shared horizontally among the single-celled organisms living on Earth at the time. Cyanobacteria are unicellular or multicellular prokaryotes that can undergo photosynthesis. They are also called blue-green algae.

They live in the soil, freshwater or marine habitats and can tolerate harsh environmental conditions same as bacteria. Cyanobacteria can form spherical-shaped, filamentous or sheet-like colonies covered with mucilaginous, sheet-like structures.

Heterocysts are the nitrogen-fixing cyanobacteria. The main photosynthetic pigment of cyanobacteria is chlorophyll-a while the accessory pigments are phycocyanin and phycoerythrin. However, some cyanobacteria are saprotrophs. Blooming cyanobacteria produce cyanotoxins that can be poison to humans and animals.

Bacteria refer to a member of a large group of unicellular microorganisms which have cell walls but lack organelles and an organized nucleus, including some which can cause disease while cyanobacteria refer to a division of microorganisms related to bacteria but are capable of photosynthesis.

Bacteria occur in each and every habitat on earth while cyanobacteria mainly occur in the presence of sunlight and moisture. Bacteria are unicellular while cyanobacteria can be either unicellular or multicellular.