B4 Enzymes Flashcards
What are enzymes?
Enzymes are proteins that function as biological catalysts.
They speed up the rate of chemical reactions without being changed or used up in the reactions.
Why are they biological?
They are biological because they are made in living cells.
Why are biological catalysts necessary to all living organisms?
They are necessary to all living organisms as they maintain reaction speeds of all metabolic reactions (the reactions that keep organisms alive) at a rate that can sustain life.
Explain how they are made from protein.
Enzymes are made of proteins. The amino acids in the protein have bonds within them that hold the enzyme into the correct shape.
What does it mean if an enzyme denatures?
Denaturing is when bonds between the amino acids break, causing the enzymes to lose their shape.
What is the lock and key model?
It is a model used to describe how enzymes work. In the model, the enzyme and substrate join together just like a key entering a lock. The shape of the key (substrate) is important to determine whether it fits into the lock (enzyme).
What is the area of the enzyme that the substrate binds to called?
The substrate binds to the active site of the enzyme.
What is enzyme specificity?
Enzyme specificity refers to the fact that only enzymes with a specific shape can join together with the specific substrate.
Enzymes and substrates are complementary to each other.
This results in each enzyme mostly just catalysing one type of reaction.
How do enzymes work?
Enzymes and substrates move around randomly due to their kinetic energy. Sometimes the active site and substrates collide and join together, forming an enzyme-substrate complex. This is when the catalysis (reaction) occurs and the product is created. Once the reaction is done, the product diffuses away.
How does temperature affect enzymes and rate of reaction?
As temperature increases, so does the kinetic energy of the molecules in the solution. There are more collisions and more enzyme-substrates complexes. This causes the rate of reaction to increase.
What is the optimum reaction?
The optimum reaction is the temperature with the highest rate of reaction.
How can temperature cause enzymes to denature?
Eventually, the kinetic energy is so high that it causes the bonds holding the enzymes together to break. When the bonds break, the enzyme loses its shape and becomes denatured. This means that the substrate can no longer fit into the active site and the reaction stops.
Explain the enzyme structure.
Enzymes have a specific 3D structure in which the shape of the active site allows them to bind to their substrate and catalyse reactions. The 3D shape is held in place by chemical bonds between the amino acids in the protein of the enzyme.
How does pH affect enzymes and the rate of reaction?
Increasing or decreasing the pH from the normal pH for that enzyme causes the bonds holding the protein together the break. When the bonds break, the active site of the enzyme loses its shape and becomes denatured. The substrate can then no longer fit into the active site and the reaction stops.
What does the optimum pH mean?
The optimum pH is the pH at which the rate of reaction is the highest for each enzyme.
