1) Cells use primarily two ways of storing potential energy: 1) as concentration
ID: 191805 • Letter: 1
Question
1) Cells use primarily two ways of storing potential energy: 1) as concentration gradients and 2) in molecules. A) Explain how energy can be stored in these two forms and how it can be used to do other work. B) Propose an analogy that can explain these forms of energy storage using everyday items.
2) You have been assigned to lead a lab that takes plant material and converts it into ethanol for fuel. The process relies entirely on enzymes that break down the cellulose into ethanol. How would each of the following factors affect the efficiency of your task: temperature, pH, enzyme concentration, substrate concentration, allosteric inhibitor, competitive inhibitor, allosteric activator? For each factor, explain what would happen if you double it and what would happen if you cut it in half.
Explanation / Answer
Molecules: Cells use this way of storing the potential energy in the form of the chemical bonds in molecules like glucose, fats, proteins, starch, and glycogen. When needed they undergo oxidation in the cells with help of many enzymes and through different cycles like glycolysis, citric acid cycle, beta-oxidation of fatty acids to yield the energy.
Concentration gradient: The best example is that of the concentration gradient of protons across the intermitochandrial membrane of mitochondria. When NADH is broken down to electrons and protons, electrons go through the ETC chain and energy is released at each step. The released energy is used to pump the protons from matrix to the intermembrane. Therefore, a concentration gradient is formed between the matrix and intermitochandrial membrane. This concentration gradient is used to synthesize ATP when these proton fall back through ATP synthase complex from higher to lower concentration of protons.
b) Propose an analogy that can explain these forms of energy storage using everyday items.
Molecules Example: The best example in this case may be the storage of the power in the battery when they are charged and when needed for example when light is off, can be utilized in the form of inverter
Concentration gradient Example: Water at the top of a waterfall is at a high gradient when allowed to fall, falls on the wheel and is used to rotate the machine and grinding of grains
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