Question

Phototrophic bacteria have
(a) Chloroplast
(b) Grana
(c) Chromatophore
(d) Carotene

Answer 1

A phototrophic bacteria is capable of entrapping solar energy and utilizing the synthesis of complex food materials due to the presence of some pigments which are present in membrane-bound vesicles.

Complete Step by Step Answer: Phototrophic bacteria have chromatophore which are membrane-bound vesicles which contain pigments like bacteriochlorophyll (bacterio purpurin) and bacterioviridin. The nutrition in bacteria is of two types i.e., autotrophic and heterotrophic. Purple sulphur bacteria and green sulphur bacteria are the most familiar examples containing pigment bacteriochlorophyll, bacterio purpurin, and bacterioviridin respectively.
In bacterial photosynthesis, water is not the source of the electron that acts as reducing power to convert carbon dioxide into glucose. The bacteria obtain reducing power from various compounds such as hydrogen sulphide, thiosulphate, or even some organic compounds. No oxygen is evolved as it does not involve the splitting of water. Hydrogen released by various compounds is picked up by ${ NAD }^{ + }$ which gets reduced to ${ NAD }{ H }_{ 2 }$ acting as reducing power. ${ NAD }{ H }_{ 2 }$ along with ATP, produced generally by entrapping solar energy are used to reduce carbon dioxide to glucose.
The formula for Anoxygenic Photosynthesis:
${ CO }_{ 2 }+2{ H }_{ 2 }A+LightEnergy\longrightarrow \left[ { CH }_{ 2 }O \right] +2A+{ H }_{ 2 }O$
So, the answer is ‘Chromatophore’.

Note: - Bacteria having an autotrophic mode of nutrition may be photoautotrophs and chemoautotrophs, carrying out photosynthesis and chemosynthesis respectively. - Bacterial photosynthesis, however, differs from the photosynthesis of higher plants and is not liberating oxygen. This type of photosynthesis is known as anoxygenic. -Photolithotrophic bacteria are the sulfur compound using bacteria whereas photoorganotrophic bacteria are non-sulfur compounds using bacteria. -Bacteria synthesizing food from inorganic material instead of light as the energy source is known as Chemosynthetic autotrophic bacteria.