Activation Energy quiz #1 Flashcards
Activation Energy quiz #1
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What are the four primary factors that contribute to the activation energy barrier in biochemical reactions, and how do enzymes lower the activation energy associated with each factor?
The four primary factors are entropy, proper orientation of substrates, distortion of the substrate, and solvation. Enzymes lower activation energy by: (1) reducing entropy by restricting substrate motion, (2) ensuring proper orientation of substrates for effective collisions, (3) stabilizing the transition state and substrate distortion via the induced fit model, and (4) removing hydration shells (desolvation) to prevent solvent interference. How does the removal of hydration shells (solvation) by enzymes affect the activation energy and the rate of biochemical reactions?
Enzymes remove hydration shells from substrates, which prevents water molecules from interfering with substrate interactions. This desolvation lowers the activation energy, thereby increasing the rate of biochemical reactions. What is activation energy and how does it affect the speed of a biochemical reaction?
Activation energy is the energy barrier between reactants and the transition state that must be overcome for a reaction to occur. A higher activation energy slows down the reaction, while a lower activation energy speeds it up. List the four primary factors that contribute to the activation energy barrier in biochemical reactions.
The four primary factors are entropy, proper orientation of substrates, distortion of the substrate, and solvation. How do enzymes reduce the entropy factor to lower activation energy in biochemical reactions?
Enzymes reduce entropy by restricting the random motion of substrates, bringing them closer together and increasing the likelihood of effective collisions, which lowers the activation energy. Why is proper orientation of substrates important for biochemical reactions, and how do enzymes help?
Proper orientation ensures that functional groups of substrates are aligned for a successful reaction. Enzymes use binding energy to orient substrates correctly, increasing the chances of reaction and lowering activation energy. Explain how substrate distortion contributes to activation energy and how enzymes address this factor.
Distortion of the substrate into a high-energy transition state increases activation energy. Enzymes stabilize the distorted transition state via the induced fit model, lowering the energy required and speeding up the reaction. What role does solvation (hydration shells) play in activation energy, and how do enzymes influence this?
Hydration shells around substrates can interfere with reactions and increase activation energy. Enzymes remove these shells (desolvation), preventing interference and lowering activation energy. How does the removal of hydration shells by enzymes affect the rate of biochemical reactions?
By removing hydration shells, enzymes prevent water molecules from blocking substrate interactions, which lowers activation energy and increases the reaction rate. How can enzymes decrease local entropy in a reaction system while still increasing universal entropy?
Enzymes decrease local entropy by restricting substrate motion, but the release of water molecules from hydration shells increases universal entropy, similar to the hydrophobic effect.
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