Biochemistry: Enzymes and Catalysts

Questions and Answers

What is a catalyst?

A substance that increases the rate of a chemical reaction by reducing the amount of energy needed to start the reaction.

What is an enzyme?

An organic catalyst that catalyzes (helps) reactions in living organisms.

What is the active site and what is its job?

A specially-shaped area of the enzyme that fits around the substrate. It is where the enzyme grabs onto the substrate.

What is a substrate?

The biological molecule that the enzyme will work on. Signup and view all the answers

What is a product?

When the enzyme lets go of the substrate, it returns to normal and is able to do another reaction. The substrate is now different and is now called the product. Signup and view all the answers

Explain how an enzyme works using the terms from 1-5.

The enzyme grabs onto the substrate in a special area called the active site. The active site is an area of the enzyme that fits around the substrate. A catalysis happens. Catalysis is when the substrate is changed. It could be broken down or combined with another molecule to make something new. The enzyme lets go, returns to normal and is ready to do another reaction. The substrate is no longer the same, it is now called the product. Signup and view all the answers

What is denaturing and what causes it to occur?

Denaturing occurs when the control changes the enzyme's shape. Signup and view all the answers

What 4 things can affect the way enzymes work? List them.

Temperature, activators, pH levels, inhibitors. Signup and view all the answers

How can a lock and key be used to describe an enzyme?

A door that is locked needs a key that is just the right shape to fit in that lock. Enzymes work in a similar way. Enzymes complete very specific roles and do nothing else. Signup and view all the answers

Why do enzymes generally only bind to one type of substrate?

Because they do very specific jobs and nothing else. Signup and view all the answers

Explain how enzymes work using activation energy and compare curves.

Enzymes are biological catalysts. Catalysts lower the activation energy for reactions. Signup and view all the answers

How does temperature affect enzyme activity? Use the word denature.

Raising temperature generally speeds up a reaction. Extreme high temperatures can cause an enzyme to lose its shape (denature) and stop working. Signup and view all the answers

Using graph 3, explain how pH affects activity.

Each enzyme has an optimum pH range. Changing the pH of this range will slow enzyme activity. Signup and view all the answers

Study Notes

Catalysts and Enzymes

Catalysts increase chemical reaction rates by lowering activation energy.
Enzymes are organic catalysts that facilitate biochemical reactions in living organisms.

Active Site and Substrate

The active site is a uniquely shaped region of the enzyme that binds to the substrate.
Substrates are the biological molecules upon which enzymes act.

Enzyme Function

Enzymes bind to substrates at the active site, enabling a chemical reaction (catalysis) to occur.
After the reaction, the enzyme releases the transformed substrate, now referred to as the product, and can catalyze additional reactions.

Denaturation

Denaturation occurs when an enzyme's shape is altered, often due to changes in temperature, pH, or the presence of poisons.
This alteration can prevent the enzyme from functioning effectively.

Factors Affecting Enzyme Activity

Temperature changes can alter enzyme shape and function, affecting reaction rates.
Activators enhance enzyme activity, allowing better binding to substrates.
pH levels impact protein structure; extreme pH conditions can cause denaturation.
Inhibitors can reduce enzyme activity: competitive inhibitors block the active site, while allosteric inhibitors modify the enzyme's shape.

Lock and Key Model

Enzymes can be described using the lock and key analogy, where each enzyme is a specific lock and each substrate is a unique key, emphasizing their specificity in catalysis.

Specificity of Enzymes

Enzymes typically bind to only one type of substrate, due to their specialized functions.

Activation Energy and Reaction Rates

Enzymes lower the activation energy of reactions, leading to faster reaction rates compared to uncatalyzed processes.

Temperature Effects on Enzyme Activity

Increasing temperature usually accelerates reactions, while extreme heat can denature enzymes, halting their activity.

pH and Enzyme Activity

Each enzyme has an optimal pH range that supports its activity; deviations from this range can slow down functioning and impact overall reaction rates.

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Description

Explore the fascinating world of enzymes and catalysts in biochemical reactions. This quiz covers their functions, the importance of active sites, the process of denaturation, and factors that affect enzyme activity. Test your knowledge on how these biological catalysts operate and their role in living organisms.