Does Chemosynthesis Require No Light
Does Chemosynthesis Require Oxygen
does chemosynthesis require oxygen
Either theory requires the synthesis of organic matter, which necessarily involves the participation of an energy source. Although there are many plausible energy sources for the generation of organic compounds, one of the most conspicuous sources on Earth is its internal heat, which is released in many environments. Such is the case of anomalously high thermal gradients around volcanoes and volcanic hot springs (Lathe, 2004, 2005), which can be subaerial and submarine—some with temperatures that may range from 90° to > 400 °C (Russell and Hall, 1997; Kelley et al., 2001). Processes driven by external sources for energy include many other interfaces such as those between rocks, water, air, and snow-air (Muller and Schulze-Makuch, 2006). From the point of view of prebiotic chemistry, high temperature gradients would have provided the necessary energy flux to promote chemical reactions. But at the same time, however, such gradients could have been harmful to organic compounds, thus promoting the degradation of the synthesized products (Muller and Schulze-Makuch, 2006).
All organisms, animals and plants, must obtain energy to maintain basic biological functions for survival and reproduction. Plants convert energy from sunlight into sugar in a process called photosynthesis. Photosynthesis uses energy from light to convert water and carbon dioxide molecules into glucose (sugar molecule) and oxygen (Figure 2). The oxygen is released, or “exhaled”, from leaves while the energy contained within glucose molecules is used throughout the plant for growth, flower formation, and fruit development.
Since respiration does not require light ..
Li, J., Wang, X., Klein, M.T., Brill, T.B., 2002, Spectroscopy of hydrothermal reactions, 19: pH and salt dependence of decarboxylation of α‐alanine at 280–330° C in an FT‐IR spectroscopy flow reactor: International Journal of Chemical Kinetics, 34, 271-277.
On the other hand, probably one of the most important characteristics of hydrothermal vents is their high mineralogical diversity. A broad array of minerals could have acted as catalytic inorganic surfaces that favored the formation of organic molecules. Such mineralogical complexity implies the induction of important chemical gradients, thus favoring the interaction between electron donors (e.g., methane, hydrogen, formate) and electron acceptors (e.g., carbon dioxide, nitrate, nitrite, sulfite, native sulfur and ferric iron). As a consequence, these reactions would yield complex organic molecules aided by pH and thermal gradients, and perhaps also by mineral fracturing and fluid flow (Russell and Hall, 1997; Russell et al., 2013).
Respiration requires an intake of oxygen ..
These hydrothermal systems (submarine or sublacustrine) can be divided into those linked to magmatism as both source for heat and chemical components, and those associated with venting of basinal brines. Such environments correspond, respectively, to volcanogenic massive sulfide (VMS) and sedimentary-exhalative (SEDEX) deposits and their present-day analogues. Paleo-hydrothermal systems associated with metalliferous deposits in black shales may be likely candidates as well. All theoretical and experimental approaches to prebiotic reactions have been carried out considering VMS-like hydrothermal systems, while neglecting the others. SEDEX systems and those associated with metalliferous black shales provide all geological and physicochemical characteristics that would have favored prebiotic reactions as effectively as VMS systems, like the necessary temperature gradients, euxinic environments, and a wide range of depths of formation (see Table 1). The problem in the involvement of SEDEX systems with prebiotic reactions resides in the age of the oldest examples of such systems, as no known deposits are older than late Paleoproterozoic (ca. 1.8 Ga; Lydon, 1996). Metalliferous black shales can be significantly older (middle Paleoproterozoic, ca. 2.1 Ga or older; Mossman et al., 2005) than SEDEX deposits. However, neither type has yet been found to be old enough as to be coeval with prebiotic processes or, least of all, be involved with them. In contrast, Archean VMS deposits are numerous (ca. 3.5 Ga; Barrie and Hannington, 1999). The striking lack of Archean SEDEX deposits can be associated with the limiting effect of high reduced iron contents on the activity of reduced sulfur in anoxic oceans (sic, Goodfellow, 1992) in which metals in hydrothermal fluids […] were dispersed because a lack of reduced sulfur to precipitate them (sic, Misra, 1999). Therefore, it is likely that SEDEX-type hydrothermal systems did effectively exist during the Archean, despite being unable to generate sulfide deposits because reduced sulfur in the oceans would have been previously “sequestered” by iron to precipitate iron sulfides directly from seawater. After the oxygenation of Earth’s oceans SEDEX deposits formed, during worldwide anoxic events of the Paleozoic, as might also be the case for Proterozoic deposits (Misra, 1999).
Acidic fluids from either deep or shallow hypogene sources generate alteration assemblages that result from extremely reactive to relatively mild reactions between fluids and host rocks, from proximal to distal areas to hydrothermal upflow, respectively. No surface sinter deposits, either carbonate- or silica-rich, can be expected from highly reactive high-sulfidation type fluids. In this environment, silica is the only residue after extreme acid leaching of every other mineral, or as a late overprint. Common hydrothermal manifestations of the high-sulfidation type are high-temperature solfataras and fumaroles centered on recent volcanic edifices, and hyper-acidic crater lakes. Near-neutral low-sulfidation type fluids, on the contrary, may develop sinter deposits in hot spring environments unless the hydrothermal discharge occurs in high-relief terrains. Common hydrothermal manifestations of the low-sulfidation type are hot springs and geysers. Common manifestations associated with steam-heated grounds are fumaroles, steaming grounds, and mud pots (or mud “volcanoes”). The position of the groundwater table is sensitive to seasonal variations in rainwater availability, climatic and tectonic changes, or several other phenomena (e.g., Sillitoe, 2015).
it is not the lack of oxygen ..
releasing process that does not require oxygen.) ..
Lack of Oxygen Not a Showstopper For Life Portal to the Universe
Photosynthesis vs. Chemosynthesis: What’s the …
Chemosynthesis: What's the Difference ..
How does chemosynthesis differ from photosynthesis? …
How does chemosynthesis differ from photosynthesis
Although the cuticle provides important protection from excessive water loss, leaves cannot be impervious because they must also allow carbon dioxide in (to be used in photosynthesis), and oxygen out. These gases move into and out of the leaf through openings on the underside called stomata (Figure 3b). After carbon dioxide enters the leaf through stomata it moves into the mesophyll cells where photosynthesis occurs and glucose is constructed.
Does photosynthesis require water? | Yahoo Answers
A hydrothermal system is an environment where there is a flow of hot fluids beneath and up to the surface of the Earth. Hydrothermal vents are systems whose heat source is the underlying magma or hot water generated by convection currents due to high thermal gradients. Hydrothermal fossil deposits have also been recognized in impact craters. Besides Earth, the other place in the Solar System that shows evidence of past impact-induced hydrothermal systems is Mars. The circulation of hydrothermal solutions and interaction with country rocks leads to the precipitation of different mineral phases. In fact, hydrothermal vents, due to their characteristics (redox potential, abundance of organic matter and the presence of certain minerals), have been proposed as places where chemical evolution could have occurred. In this article, a review of hydrothermal environments (submarine, subaerial and impact-induced) and their advantages and disadvantages as primitive environments is presented. Thus far, the synthesis of organic compounds in simulation experiments has been achieved, although the role of prebiotic processes in these environments is still ill-defined. The conditions accompanying white vents are perhaps the best suited for the synthesis of organic molecules; however, this synthesis could have also occurred around black vents, where favorable temperature gradients are present.
2009-12-14 · Does photosynthesis require water
The quest to explain how life originated on Earth is an old and unsolved topic. Several scientific hypotheses try to explain how life emerged as a result of the physicochemical interactions between organic molecules and the physical environment. The experimental evidence of chemical synthesis under conditions that possibly existed on early Earth provides support for the hypothesis of chemical evolution. The precise mechanism that led to the transformation of organic compounds to simple biological entities is still an open problem nonetheless. Two theories attempt to explain how life appeared: the “gene first” theory and the “metabolism first” approach (e.g., Bada and Lazcano, 2003; Delaye and Lazcano, 2005). According to the genetic approach, prebiotic soup produced organic compounds that gave rise to the first genetic systems; whereas the metabolic theory proposes the existence of a rudimentary primary metabolism (Orgel, 2000, Lazcano, 2010; Luisi, 2014). Both theories have been supported by several experimental as well as theoretical results (Orgel, 1998). Such is the case of the synthesis of many important organic compounds for present living beings—including some amino acids, nitrogenous bases, carboxylic acids and sugars. However, the formation of biological polymers, and how the relationship between proteins and nucleic acids evolved is still a far too complex and unresolved problem.
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