Topic 8.1 - Metabolism Flashcards
What is metabolism?
Metabolism refers to the chemical reactions that occur in living things in order for them to maintain life
What role do enzymes play in the metabolic pathway?
Enzymes catalyze each reaction along the metabolic pathway
Outline the types of metabolic processes
Some metabolic pathways are anabolic, which is the build up of organic molecules. Some are catabolic, which is the break down of large organic molecules into smaller ones
Outline the types of metabolic pathways
Some metabolic reactions are cycles (krebs cycle) and some are linear chains (glycolysis)
What is activation energy?
Activation energy is the energy needed to weaken and break the chemical bonds of the substrate, and therefore needs to be overcome in order for a chemical reaction to occur.
How do enzymes work?
They lower the activation energy
When does enzyme inhibition occur?
Enzyme inhibition occurs when molecules bind to enzymes and decrease their activity.
When does competitive inhibition occur?
Competitive inhibition occurs when a molecule that is similar in shape to the substrate competes with the substrate for access to the active site and decreases the number of times a substrate interacts with the enzyme
When does non-competitive inhibition occur?
Non-competitive inhibition occurs when an inhibitor does not compete with for the active site with the substrate, but binds to a separate site.
Explain non-competitive inhibition
The inhibitor essentially blocks the substrate from binding to the enzyme. Since there is less enzyme/substrate interactions, the chemical reaction rate decreases.
Is competitive inhibition reversible?
Yes, competitive inhibition is usually reversible but can be irreversible in some cases.
Can competitive inhibition be overcome?
Yes, competitive inhibition can be overcome by sufficiently increasing the concentrations of substrate, thereby out-competing the inhibitor.
Outline an example of competitive inhibition
An example of competitive inhibition is when ethanol is introduced to compete for the active site on the enzyme alcohol dehydrogenase and inhibit the oxidation of methanol.
Is non-competitive inhibition reversible?
Non-competitive inhibition (also called allosteric inhibition) is usually reversible. However, increasing substrate concentration will not speed up the reaction or reduce the effect of the inhibitor.
Outline an example of non-competitive inhibition.
An example of non-competitive inhibition is when ATP acts as an allosteric inhibitor in the conversion of glycogen to glucose phosphate in a metabolic pathway. ATP binds to the enzyme glycogen phosphorylase that catalyzes this reaction. This prevents the over production of ATP and glucose if it is not needed.
