Enzymes

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Enzyme Noun

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[en-zahym]

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Enzyme

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A protein that acts as a biological catalyst, speeding up chemical reactions in living organisms without being consumed.

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Example: An enzyme binds to a specific molecule (substrate), changes it into new molecules (products), and then releases them, ready to work again.

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Catalyst Noun

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[kat-l-ist]

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Catalyst

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A substance that increases the rate of a chemical reaction without undergoing any permanent chemical change itself.

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Example: A catalyst helps reactants combine by providing an easier path that requires less energy, shown as a smaller 'hill' to climb compared to the reaction without a catalyst.

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Activation Energy Noun

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[ak-tuh-vey-shuhn en-er-jee]

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Activation Energy

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The minimum amount of energy required for reactants to transform into products during a chemical reaction.

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Example: This graph shows that a chemical reaction needs a certain amount of energy to start (the 'hill'). An enzyme acts like a shortcut, lowering the 'hill' so the reaction can happen more easily.

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Substrate Noun

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[suhb-streyt]

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Substrate

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The reactant molecule that binds to an enzyme's active site and is converted into one or more products.

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Example: This diagram shows a substrate, the molecule an enzyme works on, shaped to fit perfectly into the enzyme's active site, like a key fitting into a lock.

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Product Noun

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[prod-uhkt]

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Product

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A substance that is formed as the result of a chemical reaction that has been catalyzed by an enzyme.

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Example: An enzyme binds to substrates, changes them in a chemical reaction, and then releases the new substance, which is called the product.

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Active Site Noun

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[ak-tiv sahyt]

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Active Site

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The specific region on an enzyme's surface where the substrate binds and the catalytic reaction takes place.

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Example: This diagram shows the active site as the specific region on an enzyme where a substrate molecule binds, like a key fitting into a lock.

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Denaturation Noun

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[dee-ney-cher-ey-shuhn]

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Denaturation

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The process where an enzyme loses its functional three-dimensional structure due to extreme conditions, rendering it inactive.

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Example: An enzyme's active site has a specific shape to fit its substrate. Denaturation, often by heat or pH changes, alters this shape, so the substrate no longer fits.

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Specificity Noun

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[spes-uh-fis-i-tee]

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Specificity

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The characteristic of an enzyme to catalyze only a single chemical reaction or a specific class of related reactions.

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Example: An enzyme's active site has a specific shape that only fits a particular substrate, similar to how only one specific key fits a lock.

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Optimum Temperature Noun

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[op-tuh-muhm tem-per-uh-cher]

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Optimum Temperature

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The specific temperature at which an enzyme exhibits its highest rate of catalytic activity and functions most effectively.

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Example: This graph shows that an enzyme's activity is highest at a specific temperature, called the optimum temperature, and decreases if the temperature is too low or too high.

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Optimum pH Noun

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[op-tuh-muhm pee-eych]

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Optimum pH

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The specific pH level in the surrounding environment at which an enzyme demonstrates its maximum catalytic activity.

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Example: This graph shows that an enzyme works best at a specific pH, called the optimum pH, where its activity is at its peak.