Enzymes Flashcards
What is an enzyme?
Enzymes are proteins that speed up chemical reactions inside cells and act as biological catalysts
What is the function of enzymes?
Enzymes speed up reactions by lowering the activation energy needed for the reaction to occur
Why is the shape of an enzyme important?
The shape of an enzyme is crucial because it determines how the enzyme interacts with specific substrates
What are the two main types of reactions enzymes can catalyse?
Enzymes can either break down molecules or join molecules together
What theory describes how enzymes work?
The ‘lock and key’ theory describes how enzymes work
What is the active site?
The active site is a specific region on an enzyme where the substrate binds to form an enzyme substrate complex
What is a substrate?
A substrate is a molecule that reacts with the enzyme
How must the substrate fit with the enzyme?
The substrate must fit perfectly into the enzymes active site for the active site to do its job properly
What forms when an enzyme and substrate bind together?
An enzyme substrate complex
What happens to the enzyme after the reaction is complete?
The enzyme remains unchanged and is available for another reaction
What happens to the substrate after it reacts with the enzyme?
The substrate is converted into products, which are then released from the enzyme
What is the equation for an enzyme reaction involving substrates and products?
Enzyme + substrate—> enzyme substrate complex
What happens to enzyme activity as temperature increases up to the optimum?
Enzyme activity increases because the rate of reactions rises with temperature, leading to more collisions between enzymes and substrates
What occurs to enzymes at temperatures beyond the optimum?
Enzymes become denatured due to the active site changing shape, so they can no longer bind effectively to substrates
Define ‘optimum temperature’
The temperature at which enzyme activity is at its highest before denaturing
What is the result of the enzyme denaturing on the enzymes functions?
The enzyme denaturing alters the shape of the active site, preventing substrates binding to form a enzyme substrate complex and decreasing enzyme activity
How does pH affect enzyme activity?
Enzymes have an optimum pH, where they function best. Anywhere below of above the optimum pH causes the enzyme to denature and the active site to change shape
What happens to enzymes in very acidic or alkaline conditions?
Enzymes become denatured, causing their active site to change shape and reducing their ability to catalyse reactions
