Topic 5: Enzymes Flashcards
(16 cards)
What are enzymes?
Enzymes are proteins that act as biological catalysts in all metabolic reactions, speeding up chemical processes without being used up.
What is the role of enzymes in metabolic reactions?
Enzymes speed up metabolic reactions by lowering the activation energy required for the reactions to occur.
What is an enzyme-substrate complex?
The enzyme-substrate complex is a temporary structure formed when an enzyme binds to its specific substrate.
What is the “Lock and Key” model?
The “Lock and Key” model describes how an enzyme’s active site fits precisely with its substrate, similar to how a key fits into a lock.
How does temperature affect enzyme activity?
Increasing temperature raises kinetic energy, leading to more frequent collisions, thus speeding up reactions. However, high temperatures can denature the enzyme, changing its shape and reducing activity.
What is denaturation in enzymes?
Denaturation occurs when an enzyme’s structure changes due to extreme temperature or pH, causing it to lose its function.
What is the optimum temperature for enzymes in the human body?
The optimum temperature for enzymes in the human body is approximately 37°C.
How does pH affect enzyme activity?
Enzymes have an optimum pH, and changes in pH can cause denaturation by altering the enzyme’s shape, which prevents it from binding to the substrate.
What is the effect of extreme pH on enzyme activity?
Extreme pH can break the hydrogen bonds in an enzyme, causing it to denature and lose its ability to bind to the substrate.
Why are enzymes specific to their substrates?
Enzymes are specific to their substrates because the shape of the enzyme’s active site complements the shape of the substrate, allowing only that specific substrate to bind.
What happens to enzyme activity at low temperatures?
At low temperatures, enzyme activity is slow because molecules move less, resulting in fewer effective collisions.
What is the effect of temperature on the frequency of effective collisions between enzymes and substrates?
As temperature increases, molecules move faster, leading to more frequent and effective collisions, which increases enzyme activity.
What is the effect of pH on the active site of an enzyme?
Changes in pH can alter the shape of the enzyme’s active site, preventing it from fitting with the substrate, and thus, the enzyme can no longer function.
What are the types of enzymes with different optimum pH?
Pepsin works best in acidic conditions (pH 2), while amylase works best in neutral conditions (pH 7).
What is the role of enzymes in digestion?
Enzymes like amylase, protease, and lipase help break down food into simpler molecules that the body can absorb.
What happens when the temperature exceeds the optimum for an enzyme?
When the temperature exceeds the enzyme’s optimum, the enzyme becomes denatured and can no longer bind with the substrate, losing its function.
