BIOCHEMISTRY
ENZYMES AND METABOLISM
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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substrates and enzymes have less kinetic energy and experience fewer collisions at a low temperature.
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enzymes denature at low temperatures
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an enzyme’s active site changes in shape at lower temperatures
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the saturated phospholipids that make up an enzyme pack very close together at low temperatures.
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Detailed explanation-1: -At low temperatures enzyme activity is low because the enzyme and substrate molecules have less kinetic energy so there are fewer collisions between them. At the optimum temperature, the kinetic energy in the substrate and enzyme molecules is ideal for the maximum number of collisions.
Detailed explanation-2: -Why will most enzyme-controlled reactions occur slowly at a low temperature? A lower temperature means the molecules have less elastic energy, so they do not bind together as frequently. A lower temperature means the molecules have more kinetic energy, so they collide frequently.
Detailed explanation-3: -In a cold environment, enzymes function more slowly because the molecules are moving more slowly. The substrate bumps into the enzyme less frequently. As the temperature increases, molecules move more quickly, so the enzyme functions at a higher rate.
Detailed explanation-4: -Because enzymes are proteins, they are denatured by heat. Therefore, at higher temperatures (over about 55°C in the graph below) there is a rapid loss of activity as the protein suffers irreversible denaturation.