Biologists refer to the movement of energy through an cosystem as \"energy flow\
ID: 95411 • Letter: B
Question
Biologists refer to the movement of energy through an cosystem as "energy flow" and not "energy cycling". Why you think they use the word flow instead of cycling? Relate your answer to the laws of thermodynamics. A series of enzymes catalyze the reaction X rightarrow Y rightarrow Z rightarrow A. duct A binds to the enzyme that converts X to Y at action remote from its active site. This binding decreases the for the enzyme. Explain this system and what function substrate, product, and enzymes serves in this system. Us appropriate terminology.Explanation / Answer
1. Basically in an ecosystem solar energy (the only source of energy for living organisms) is converted into chemical energy by plants via the process of photosynthesis (these are autotrophs). This energy is further transferred to the herbivores when they feed on plants. Herbivores are in turn fed by carnivores or they die and decompose at which stage the energy from herbivores get transferred to carnivores and decomposers. At every level, a portion of energy is utilised by the organism, a portion is lost and heat and a portion is being transferred to the next trophic level. At no stage/level, energy is transferred back. Thus, the energy coming from the sun flows in one direction and does not flow back ie., energy is not recycled.
According to first law, energy is neither created nor destroyed, but can be converted from one form to another. So, in the ecosystem – light energy from sun is converted to chemical energy which moves from one level to another.
2. In this case, product “A” decreases the activity of the enzyme which catalyzes conversion of substrate X to Y by binding to a site which is remote from the active site (site where the substrate X binds). It is a case of feedback regulation - where the end product (A) decreases the activity of the enzyme. This occurs by non-competitive inhibition - where “A” binds to the enzyme at a site remote from the active site. Therefore there is no competition with respect to binding sites. But, due to binding of both “X” and “A” to the enzyme (at two different sites), the process of conversion of Enzyme-Substrate complex to “Y” is decreased.
Functions of -
Substrate – “X”, Binds to the enzyme, forms Enzyme- Substrate complex and gets converted to another form (Y).
Product – “A”, Causes feedback regulation by non-competitive inhibition.
Enzyme - Catalyses conversion of “X” to “Y”
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