Proteins and Enzymes - 12 Biology

Enzyme Purpose

100

What is the function of enzymes in biochemical reactions?

Enzymes speed up biochemical reactions by lowering the activation energy.

200

How do enzymes lower the activation energy of reactions?

Enzymes lower the activation energy by providing an alternative reaction pathway.

300

Describe the role of enzymes in the context of an organism's proteome.

Enzymes are proteins that facilitate biochemical reactions, forming part of the organism's proteome.

400

What is a catalyst, and how does it relate to enzyme function?

A catalyst is a substance that increases the rate of a reaction without being consumed, and enzymes serve this role in biological systems.

500

Explain how enzymes can be specific to substrates in biochemical pathways.

• Enzymes are specific due to their active site structure matching specific substrate shapes.

Activation Energy

100

What is activation energy?

• Activation energy is the minimum energy required to initiate a chemical reaction.

200

Why is activation energy important for biochemical reactions?

• Activation energy is important because it determines the rate at which a reaction can occur.

300

How do enzymes affect the activation energy of reactions?

Enzymes lower activation energy, making it easier for reactions to occur.

400

Compare the activation energy of catalyzed vs. uncatalyzed reactions.

• Catalyzed reactions have lower activation energy compared to uncatalyzed reactions, resulting in faster reaction rates.

500

Give an example of a reaction with high activation energy and how an enzyme might assist.

• An example is the combustion of wood, which has high activation energy, and enzymes can help facilitate chemical changes in biological systems.

Catabolic vs Anabolic

100

Define catabolic reactions with an example.

• Catabolic reactions break down molecules and release energy (e.g., glycolysis).

200

Define anabolic reactions with an example.

• Anabolic reactions build complex molecules and require energy (e.g., protein synthesis).

300

What is the primary difference between catabolic and anabolic pathways?

• The primary difference is that catabolic pathways release energy by breaking down molecules, while anabolic pathways consume energy to build them.

400

How do enzymes facilitate both catabolic and anabolic reactions?

• Enzymes facilitate both pathways by catalyzing the necessary reactions for breaking down or building up molecules.

500

Explain how cellular respiration is a catabolic process while photosynthesis is anabolic.

• Cellular respiration is a catabolic process as it breaks down glucose to produce energy, while photosynthesis is anabolic as it synthesizes glucose from carbon dioxide and water.

Denaturation

100

What is denaturation in terms of proteins?

• Denaturation is the process where proteins lose their structure and function due to external factors.

200

List two factors that can cause denaturation of enzymes.

• Factors include high temperature and extreme pH levels.

300

How does denaturation affect enzyme function?

• Denaturation affects enzyme function by altering the active site's shape, preventing substrate binding.

400

Give an example of a situation where denaturation occurs and its impact on enzyme activity.

• An example is cooking an egg; heat denatures the proteins, changing their structure and texture.

500

Discuss the irreversible vs. reversible denaturation of enzymes.

• Irreversible denaturation permanently alters the enzyme, while reversible denaturation can restore function if conditions return to normal.

Factors Affecting Enzymes

100

How does temperature affect enzyme activity?

• Increasing temperature usually increases enzyme activity up to a certain point before denaturation occurs.

200

What impact does pH have on enzyme function?

Extreme pH levels can lead to denaturation or reduced enzyme activity.

300

How does substrate concentration influence enzyme activity?

• Higher substrate concentration generally increases enzyme activity until the enzyme becomes saturated.

400

Describe the difference between competitive and non-competitive enzyme inhibitors.

Competitive inhibitors bind to the active site, while non-competitive inhibitors bind to a different site and change enzyme shape.

500

Explain how changes in enzyme concentration can affect the rate of biochemical reactions.

Increasing enzyme concentration can increase the rate of reaction, provided substrate is available.