Flashcards · Biology · Homeostasis
Why Homeostasis Matters: Enzymes and Osmosis
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What is thermoregulation?
The control of body temperature.
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What is osmoregulation?
The control of the water content of the body.
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What is the optimum temperature of human enzymes?
About 37 °C.
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What happens to enzymes when it is too cold?
They work more slowly, because there are fewer collisions.
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What happens to enzymes when it is too hot?
They are denatured, and stop working.
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Is denaturing reversible?
No, the enzyme does not return to its shape when it cools.
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What is denaturing?
A change in the shape of the enzyme, including the active site.
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Why do animal cells burst in pure water?
Water enters by osmosis, and they have no cell wall.
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What happens to a red blood cell in a concentrated solution?
Water leaves by osmosis, and it shrinks.
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What happens to a red blood cell in a dilute solution?
Water enters by osmosis, and it swells and may burst.
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What does a partially permeable membrane do?
Lets some substances pass, but not others.
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Which membrane controls what enters an animal cell?
The cell surface membrane.
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How do you calculate percentage change?
Change divided by the original value, multiplied by 100.
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Why does a high temperature stop an enzyme working?
The active site changes shape, so the substrate no longer fits.
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Which organ controls the water content of the blood?
The kidney.
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Common mistake about enzymes and temperature?
Saying that enzymes are killed. They are not alive, so they are denatured.