Chapter 3 enzymes Flashcards
whats an enzyme
an organic molecule, typically a protein, that catalyses (speeds up) specific reactions.
whats a catalyst and to catalyse something
a substance capable of increasing the rate of the reaction without being used up.
Catalyse: to increase the rate of a reaction.
whats a substrate
name given to the reactant undergoing an enzyme facilitated reaction.
whats a product
the transformed molecule created in a reaction.
whats a biochemical pathway
a series of enzyme-catalysed biochemical reactions in which the product of one reaction becomes the substrate of the next reaction (also called a metabolic pathway).
whats an active site
the part of an enzyme where the substrate binds.
whats an Enzyme-substrate complex:
the structure formed when an enzyme and substrate are bound together.
whats a conformational change
a change in the 3D shape of macromolecules, like proteins.
whats activation energy
the energy required to initiate a reaction.
whats an anabolic reaction
two or more smaller molecules combine to form a larger molecule (building up).
whats a catabolic reaction
a larger molecule turning into two or more smaller molecules (breaking down).
what are enzymes and how do they work
Enzymes are organic (carbon-based) catalysts that speed up (catalyses) biochemical reactions by lowering the activation energy required to initiate a given reaction.
Enzymes bind to molecules called substrates. The substrate undergoes a chemical reaction and forms a product that leaves the enzyme. The enzyme remains unchanged from the reaction, and is free to catalyse further reactions.
Enzymes are able to ‘team up’ to work in a chain of reactions, usually in a biochemical pathway. One enzyme will catalyse a substrate into a product, which will then become the substrate of a second enzyme.
how does the reaction occur
Enzymes have an active site. This site is an area of the enzyme’s tertiary structure where the substrate binds. The active site of an enzyme and it’s substrate are complementary in shape.
When a substrate binds to the enzyme, they form an enzyme-substrate complex. The active site undergoes a conformational change which in turn causes a small change to occur in the substrate. There are hydrogen bonds and hydrophobic interactions that help keep the complex together during this change
whats a lock and key fit
Original idea of how enzymes and substrates were bound, that a substrate will fit perfectly into the active site of an enzyme (like a lock and key).
Now, it is incredibly rare for an enzyme and it’s substrate to fit perfectly together.
whats an induced fit
The preferred model of how an enzyme and a substrate are bound, that there is a slight adjustment upon binding to better fit the substrate and enzyme together.
The enzyme undergoes a conformational change to better fit the substrate
