Biology Chapter on Catalysis and Enzymes

What is the role of enzymes in chemical reactions?

How does a catalyst differ from an enzyme?

At what pH level do most enzymes typically operate optimally?

What happens to enzymes at extreme temperatures or pH levels?

In the example of hydrogen peroxide decomposition, what is the role of manganese dioxide?

What characteristic makes enzymes specific to a particular reaction?

Which of the following best describes the role of activation energy in enzymatic reactions?

What happens to the enzyme after it has catalyzed a reaction?

Which of the following factors is NOT mentioned as a mechanism of enzyme inhibition?

Which suffix is typically used to name enzymes?

Catalysis and Enzymes

Enzymes are protein molecules that speed up chemical reactions in cells.
They lower the activation energy required for a reaction to occur.
Enzymes are specific, catalyzing only 1 or 2 reactions at most, unlike inorganic catalysts.
Enzymes work best at specific temperatures and pH levels.
High temperatures and extreme pH levels can denature (inactivate) enzymes.
Enzymes are also affected by heavy metals and poisons.

Activation Energy

Activation energy is the minimum energy required for a reaction to occur.
Enzymes reduce the activation energy requirement by providing an alternative reaction pathway.
Collisions between molecules must have sufficient energy and proper orientation for a reaction to occur.
Enzymes help by making these collisions more likely.

Hydrogen Peroxide Breakdown

Hydrogen peroxide (H₂O₂) breaks down into water and oxygen (O₂).
Manganese dioxide (MnO₂) is an inorganic catalyst that speeds up this reaction.
Catalase is an enzyme that can also catalyze hydrogen peroxide breakdown, often much faster than inorganic catalysts.

Effect of temperature and pH

Enzyme activity is affected by temperature.
Increasing temperature initially increases enzyme activity, but high temperatures can denature the enzyme.
Enzyme activity is also affected by pH.
Most enzymes function best near a neutral pH of 7; some function best at acidic or alkaline conditions.
Heavy metals and poisons can inactivate enzymes.

This quiz explores the roles of enzymes and catalysts in biological reactions. It covers topics such as activation energy, enzyme specificity, and the breakdown of hydrogen peroxide. Test your understanding of how enzymes facilitate chemical processes in living organisms.