Life Sciences - Term 4 - Week 10

Enzymes are biological catalysts that speed up chemical reactions in living organisms. They are typically proteins that lower the activation energy required for reactions to occur, allowing metabolic processes to happen efficiently at body temperature. Each enzyme has a specific active site that binds to its substrate, forming an enzyme-substrate complex, which facilitates the conversion of substrates into products.

Several factors influence enzyme activity, including temperature, pH, and substrate concentration. Each enzyme has an optimal temperature and pH at which it functions best. Deviations from these conditions can lead to decreased activity or denaturation of the enzyme. Additionally, increasing substrate concentration can enhance reaction rates up to a point, after which the enzyme becomes saturated.

Consider the enzyme amylase, which catalyzes the breakdown of starch into sugars. When starch is mixed with amylase in a warm environment, the enzyme binds to the starch molecules, facilitating their conversion into maltose. This reaction demonstrates how enzymes lower the activation energy and increase the rate of reaction, making digestion more efficient.

In pairs, students will conduct an experiment to observe the effect of temperature on enzyme activity using catalase, an enzyme found in potatoes. They will measure the amount of oxygen produced when hydrogen peroxide is added to potato pieces at different temperatures. Students will record their observations and discuss how temperature impacts enzyme efficiency.

Students will complete a worksheet with questions related to enzyme structure, function, and factors affecting activity. They will be asked to explain the importance of enzymes in metabolic pathways and provide examples of specific enzymes and their substrates.

• To provide energy to cells
• To speed up chemical reactions
• To transport substances across membranes
• To store genetic information

Answer: To speed up chemical reactions

Enzymes act as catalysts, increasing the rate of biochemical reactions without being consumed in the process.

• Temperature
• pH
• Substrate concentration
• Color of the enzyme

Answer: Color of the enzyme

The color of the enzyme does not influence its activity; however, temperature, pH, and substrate concentration do.

Answer: The active site is the region on the enzyme where substrates bind, allowing the enzyme to catalyze the conversion of substrates into products.

The active site is specifically shaped to fit the substrate, facilitating the chemical reaction.

• It becomes more active
• It denatures
• It increases in size
• It becomes a substrate

Answer: It denatures

Extreme pH levels can disrupt the hydrogen bonds and ionic bonds that maintain the enzyme's structure, leading to denaturation.

Answer: Increasing substrate concentration initially increases enzyme activity until the enzyme becomes saturated.

Once all active sites are occupied, adding more substrate will not increase the rate of reaction.

• Amylase
• Catalase
• Lipase
• Protease

Answer: Catalase

Catalase catalyzes the decomposition of hydrogen peroxide into water and oxygen, protecting cells from oxidative damage.