Enzymes | Cells | Biology | FuseSchool

Summary

Enzymes, essential proteins acting as biological catalysts, speed up reactions like photosynthesis and respiration. They work by lowering activation energy, remain unchanged post-reaction, and can be reused. Enzymes operate with substrates, fitting them into their active sites like a lock and key. They can break down or build up molecules and are sensitive to conditions like pH and temperature. Used in everyday life, from washing powders to food industries, enzymes play a crucial role in various processes.

Takeaways

• 🧬 **Enzymes are vital proteins** that facilitate numerous biological processes such as photosynthesis, respiration, and protein synthesis.
• 🔑 **Biological catalysts**: Enzymes speed up reactions by lowering the activation energy without being consumed in the process.
• 🔄 **Diverse functions**: Enzymes can break down large molecules, build them up, or transform one molecule into another.
• 💥 **Collision theory**: For an enzyme-catalyzed reaction to occur, the enzyme and substrate must collide with the right energy and orientation.
• 🔗 **Lock and key mechanism**: Enzymes are specialized, with an active site that fits a specific substrate like a lock and key.
• 🛠️ **Catalytic action**: Once the substrate is in the active site, the enzyme facilitates the reaction, producing the required product.
• 🚫 **Specificity**: Enzymes are specific; for example, protease breaks down proteins into amino acids, lipase breaks down fats, and catalase breaks down hydrogen peroxide into water and oxygen.
• 🌡️ **Optimum conditions**: Each enzyme has an optimal pH and temperature at which it functions best, beyond which it can become denatured.
• 📉 **Substrate and product concentration**: The reaction rate is affected by substrate availability and product accumulation.
• 🌟 **Practical applications**: Enzymes are used in everyday life, such as in biological washing powders to remove stains and in the food industry to enhance juice extraction.

Q & A

What is the primary function of enzymes?

Enzymes are proteins that act as biological catalysts, speeding up the rates of various chemical reactions such as photosynthesis, respiration, and protein synthesis by lowering the activation energy required for these reactions.

How do enzymes remain unchanged after catalyzing a reaction?

Enzymes are unchanged at the end of a reaction because they facilitate the reaction without being consumed or permanently altered. They can be reused for multiple reactions.

What is the role of substrates in enzyme function?

Substrates are the molecules that enzymes act upon. They must collide with the enzyme at the right speed and orientation to fit into the enzyme's active site, where the reaction occurs.

What is the 'lock and key' mechanism in enzyme-substrate interactions?

The 'lock and key' mechanism refers to the specific fit between an enzyme's active site and a substrate. The active site's shape matches the substrate's shape, allowing the substrate to bind and react within the enzyme.

Can you provide an example of an enzyme that breaks down substrates?

Yes, protease is an example of an enzyme that breaks down proteins into amino acids, while lipase breaks down fats into fatty acids and glycerol.

What is the role of catalase enzymes?

Catalase enzymes help break down hydrogen peroxide, which can be harmful if allowed to accumulate in cells, into harmless water and oxygen.

How do enzymes help in building up molecules?

Enzymes can also facilitate the building up of molecules from smaller units, although the process is the same as breaking down molecules. They catalyze the reaction by lowering the activation energy.

What are the optimum conditions for enzyme activity?

Each enzyme has specific optimum conditions, including pH and temperature, at which it works best. These conditions vary depending on the enzyme and the environment in which it operates.

Why does an increase in temperature initially increase reaction rates?

An increase in temperature provides more kinetic energy, leading to more frequent and energetic collisions between enzymes and substrates, which can increase reaction rates.

What happens to enzymes when they are exposed to temperatures above their optimum?

Above a certain temperature, enzymes can denature, losing their structure and function, which causes the reaction rate to drop.

How do enzymes affect everyday life outside of biological processes?

Enzymes are used in various industries, such as in biological washing powders to remove protein and fat stains from clothes, and in food and drink industries, like pectinase used to break down fruit cells for juice production.