Metabolic Pathways Flashcards
How are metabolic pathways controlled?
By the presence of absence of particular enzymes.
How are rates of enzyme reaction controlled?
By intracellular and extracellular signal molecules.
What is a signal molecule?
Molecule that brings about changes in a cell’s metabolism.
True or false: anabolic pathways require energy and involve biosynthetic processes.
True.
True or false: catabolic pathways release energy and involve the breakdown of molecules.
True.
Give details of substrate molecules and active sites.
Substrate molecules have an affinity for the active site of an enzyme.
The enzyme is flexible and the substrate can induce the active site to change shape by induced fit.
What is ‘induced fit’?
Change to an enzyme’s active site brought about by its substrate.
What is the name for the energy required to initiate a chemical reaction?
Activation energy.
Give details of products of enzyme reactions and active sites.
Products of enzyme reactions have a low affinity for the active site of the enzyme and are released.
What is a multi-enzyme complex?
Enzymes working in groups.
What is non-competitive inhibition?
The binding of molecules that change the shape of the enzyme and its active site so that it can no longer combine with substrate molecules.
What is competitive inhibition?
Competition for the active site of the enzyme from molecules that resemble the substrate.
Increasing substrate concentration can reduce competitive inhibition.
What is feedback inhibition?
A method of metabolic control in which the end product bonds to an enzyme that catalyses a reaction early in the pathway.
What is the meaning of the term ‘Anabolic’?
Metabolic pathways that consume energy in synthesis of complex molecules.
What does the the term ‘Catabolic’ mean?
Metabolic activity that releases energy in breakdown reactions.
