Question

energy conversion of respiration

Answer 1

Cellular respiration is a set of metabolic reactions and processes that take place in the cells of organisms to convert biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products. ... Respiration is one of the key ways a cell releases chemical energy to fuel cellular activity.

Answer 2

During the process of photosynthesis, light penetrates the cell and passes into the chloroplast. The light energy is intercepted by chlorophyll molecules on the granal stacks. Some of the light energy is converted to chemical energy. During this process, a phosphate is added to a molecule to cause the formation of ATP. The third phosphate chemical bond contains the new chemical energy. The ATP then provides energy to some of the other photosynthetic reactions that are causing the conversion of CO2 into sugars. While the above reactions are proceeding CO2 is diffusing into the chloroplast. In the presence of the enzyme Rubisco, one molecule of CO2 is combined with one molecule of RuBP, and the first product of this reaction is two molecules of PGA. The PGA then participates in a cycle of reactions that result in the production of the sugars and in the regeneration of RuBP. The RuBP is then available to accept another molecule of CO2 and to make more PGA. Which wavelengths of the solar spectrum drive photosynthesis? 

 The wavelengths of sunlight between 400nm and 700nm are the wavelengths that are absorbed by chlorophyll and that drive photosynthesis.  Energy Incident on a LeafPhotosynthesis is not a very efficient process. Of the sunlight reaching the surface of a leaf, approximately: 
 75% is evaporated15% is reflected5% is transmitted through the leaf4% is converted to heat energy1% is used in photosynthesis How do we know the O2 is derived from H2O during photosynthesis?The oxygen product of photosynthesis could originate from either the CO2 or the H2O starting compounds. To determine which of these original compounds contributed to the O2 end product, an isotopic tracer experiment was performed using 18O: 18O is a heavy isotope of oxygen H218O + CO2 yields 18O2 H2O+C1802 yields O2 Therefore, the O2 end product must originate from water and not from the carbon dioxide.  How do we know what the first products of photosynthesis are?Another isotopic tracer experiment: 14C is a radioactive isotope of carbon. 14CO2 is exposed for a brief period to a green plant that is conducting a photosynthesis in the presence of sunlight. Immediately after exposure to 14CO2, the plant's photosynthetic tissue is killed by immersing it in boiling alcohol, and all of the biochemical reactions cease. The chemical compounds in the dead tissue are all extracted and studied to determine which of them possesses the 14C. Following the briefest exposure to 14CO2, the only chemical compound that possessed 14C was PGA (phosphoglyceric acid, a three carbon molecule). Following longer periods of exposure, much of the 14C was found in a variety of compounds including glucose. By varying the length of the exposure period it was possible to identify the sequence of the reactions leading from PGA to glucose. This research was conducted by Prof. Melvin Calvin and his colleagues at the Univ. of California, Berkeley. Calvin received the Nobel Prize for this work.  
 Metabolism We have seen how plants convert sunlight into sugars. Now we need to understand how cells can use the products of photosynthesis to obtain energy. There are several possible metabolic pathways by which cells can obtain the energy stored in chemical bonds:  
  Glycolysis Fermentation Cellular respiration Glycolysis:Glycolysis can occur in either the absence or the presence of oxygen. During glycolysis, glucose is broken down to pyruvic acid, yielding 2 ATP of energy. Glycolysis occurs in the cytoplasm of cells, not in organelles, and occurs in all kinds of living organisms. Prokaryote cells use glycolysis and the first living cells most likely used glycolysis. Fermentation:During fermentation, the pyruvic acid produced during glycolysis is converted to either ethanol or lactic acid. This continued use of pyruvic acid during fermentation permits glycolysis to continue with its associated production of ATP. Cellular Respiration:Respiration is the general process by which organisms oxidize organic molecules (e.g., sugars) and derive energy (ATP) from the molecular bonds that are broken. Glucose (a sugar):C 6H12O6 Respiration is the opposite of photosynthesis, and is described by the equation:C6H12O6+6O2 ----------> 6CO2+6H2O+36ATPSimply stated, this equation means that oxygen combines with sugars to break molecular bonds, releasing the energy (in the form of ATP) contained in those bonds. In addition to the energy released, the products of the reaction are carbon dioxide and water.

Remainig is written in  comment desk of my answer