c1.1 enzymes and metabolism Flashcards
(32 cards)
What are enzymes?
Enzymes (ending in ase) are globular proteins which are biological catalysts. They speed up reactions but remain unchanged and unused.
Why are enzymes important?
Without enzymes, the chemical reactions needed to keep organisms alive would happen too slowly to sustain life. They convert substrates into products in a reaction.
What is a substrate?
The starting material in an enzyme reaction.
What is catabolism?
The degradation and breaking down of molecules.
What is anabolism?
The synthesis and building up of molecules.
What happens when enzymes are present in a reaction?
The rate of reaction increases significantly because the enzyme lowers the activation energy.
What is activation energy?
The amount of energy needed to start a reaction.
What is metabolism?
All of the catabolic and anabolic reactions happening in an organism.
What is energy yield?
The amount of usable energy generated from a metabolic pathway, typically measured in ATP molecules.
When is there an energy yield in metabolism?
When bonds are made to form the products of an enzyme-catalysed reaction.
What does it mean for enzymes to be substrate-specific?
They primarily interact with and catalyze reactions involving only one or a small group of specific substrates.
What are anabolic reactions?
Anabolic reactions involve the building of larger, complex molecules from smaller, simpler ones.
What are examples of anabolic reactions?
Formation of macromolecules from monomers by condensation reactions, such as protein synthesis, glycogen formation, and photosynthesis.
What are catabolic reactions?
Catabolic reactions break the chemical bonds in larger, more complex molecules.
What are examples of catabolic reactions?
Hydrolysis of macromolecules into monomers (digestion) and oxidation of substrates (respiration).
What is protein synthesis?
An anabolic reaction involving the joining of amino acids together via peptide bonds to form a polypeptide chain.
What is glycogen formation?
An anabolic reaction where excess glucose monomers form long chains of glycogen stored in the liver.
What is digestion?
A catabolic reaction where different enzymes break down carbohydrates, proteins, and fats.
How do enzymes work?
Enzymes have an active site where substrates bind, forming an enzyme-substrate complex to catalyze reactions.
What is the structure of the active site of an enzyme?
The active site is composed of a few amino acids essential for catalysis, shaped by the enzyme’s overall 3D structure.
What is the induced-fit model?
The model describes how an enzyme and substrate bind, changing shape slightly to facilitate bond formation or breaking.
Why does the induced-fit model change the shape of the enzyme?
The initial interaction between the enzyme and substrate is not perfectly complementary, causing a conformational change.
Why are some enzymes immobilized?
Immobilization enhances stability, allows reuse, and improves efficiency in applications like making lactose-free milk.
What factors impact how an enzyme works?
Temperature, pH, and substrate concentration.
