1.7 Enzymes Flashcards
To understand 1.7 enzymes
What are enzymes?
Enzymes are proteins that act as biological catalysts by accelerating chemical reactions.
How many different enzymes are typically found in a living cell?
About 4000 enzymes
What is a catalyst?
A substance that speeds up a reaction without being consumed; in biological systems, enzymes act as catalysts.
What is the active site of an enzyme?
The location where the substrate binds, usually a pocket or groove formed by the enzyme’s tertiary structure.
Describe the lock-and-key method
A model explaining how specific substrates (keys) fit into specific enzymes (locks) for catalysis.
What is the induced-fit method
Instead of the enzyme’s active site being a perfect fit for the substrate from the start, the enzyme changes its shape slightly when the substrate binds. This adjustment helps the enzyme bind more tightly and increases the enzyme’s range of specificity, allowing it to interact with multiple substrates. As a result, one enzyme can work on a variety of substrates, making it more versatile.
What is the enzyme-substrate complex?
The temporary complex formed when an enzyme binds to its substrate(s) before converting them into products.
What are cofactors?
Non-protein groups, often metals, that bind to enzymes and are essential for their catalytic activity.
What are coenzymes?
Organic helpers, usually from vitamins, that assist enzymes.
What factors affect how enzymes work?
Substrate concentration, temperature, and pH (acidity).
What is competitive inhibition?
When an inhibitor with a structure similar to the substrate occupies the active site, stopping the substrate from binding. The effect can be reversed by increasing substrate concentration
What is noncompetitive inhibition?
The inhibitor does not have a structure like the substrate, and it binds to another part of the enzyme. It changes the shape of the enzyme and active site so that the substrate cannot fit the altered active site. No reaction occurs, and the effect cannot be reversed by adding substrate/increasing substrate concentration.
What is allosteric regulation?
A method used by cells to control enzyme activity. Is it when a molecule binds to an enzyme and changes its shape, affecting its activity
What can happen if an enzyme is missing or defective?
It can lead to serious problems, like metabolic disorders, where the body can’t break down certain substances. For example, a missing enzyme in lactose intolerance prevents proper digestion of lactose, causing symptoms like bloating and cramps.
What is feedback inhibition?
A way to control reactions where the end product stops an earlier step from happening if there’s too much
Give an example of feedback inhibition
Isoleucine can stop the enzyme that makes it when there’s enough of it
What does the enzyme lipase do?
It helps break down lipids (fats) into smaller parts.
What reaction does sucrase catalyze?
It breaks down sucrose (sugar) into glucose and fructose.
What is enzyme specificity?
Each enzyme only works with a specific substrate or a group of similar substrates.
How do temperature changes affect enzymes?
Too high or too low temperatures can change an enzyme’s shape, making it less effective.
Why do enzymes have a unique shape?
Their shape determines which substrate they can bind to and what reaction they can speed up.
What happens to enzyme activity if the pH level changes too much?
Enzymes have an optimal pH for maximum activity. Extreme pH levels can denature (change the shape of) the enzyme, reducing its activity.
How can the concentration of substrate affect enzyme activity?
More substrate can increase the reaction rate until the enzyme is saturated.
What is saturation level in enzyme reactions?
The point where all enzyme active sites are occupied by substrate, and adding more substrate doesn’t increase the reaction rate.
