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Chlorophyll b is made by the same enzyme acting on chlorophyllide b. The same is known for chlorophyll d and f, both made from corresponding chlorophyllides ultimately made from chlorophyllide a. [39] In Angiosperm plants, the later steps in the biosynthetic pathway are light-dependent. Such plants are pale if grown in darkness.
Chlorophyll a, b, and d. Chlorophyll synthase [14] completes the biosynthesis of chlorophyll a by catalysing the reaction EC 2.5.1.62. chlorophyllide a + phytyl diphosphate chlorophyll a + diphosphate. This forms an ester of the carboxylic acid group in chlorophyllide a with the 20-carbon diterpene alcohol phytol.
Some viruses can "hide" within a cell, which may mean that they evade the host cell defenses or immune system and may increase the long-term "success" of the virus. This hiding is deemed latency. During this time, the virus does not produce any progeny, it remains inactive until external stimuli—such as light or stress—prompts it to activate.
Viruses were expected to be small, but the range of sizes came as a surprise. Some were only a little smaller than the smallest known bacteria, and the smaller viruses were of similar sizes to complex organic molecules. [14] In 1935, Wendell Stanley examined the tobacco mosaic virus and found it was mostly made of protein. [15]
Gamma phage, an example of virus particles (visualised by electron microscopy) Virology is the scientific study of biological viruses.It is a subfield of microbiology that focuses on their detection, structure, classification and evolution, their methods of infection and exploitation of host cells for reproduction, their interaction with host organism physiology and immunity, the diseases they ...
All oxygenic photosynthetic organisms use chlorophyll a, but differ in accessory pigments like chlorophyll b. [5] Chlorophyll a can also be found in very small quantities in the green sulfur bacteria, an anaerobic photoautotroph. [7] These organisms use bacteriochlorophyll and some chlorophyll a but do not produce oxygen. [7]
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Chlorophyll a is found in all chloroplasts, as well as their cyanobacterial ancestors. Chlorophyll a is a blue-green pigment [151] partially responsible for giving most cyanobacteria and chloroplasts their color. Other forms of chlorophyll exist, such as the accessory pigments chlorophyll b, chlorophyll c, chlorophyll d, [12] and chlorophyll f.