2.1 metabolic pathways Flashcards
Metabolic pathway definition
Metabolic pathways are a series of reactions inside of cells, starting with a substrate molecule and ending with a product molecule, which are controlled and integrated by enzymes.
Types of metabolic pathway
Reversible, irreversible and alternative
Reversible reactions
A metabolic pathway where product molecules can be converted back into substrate molecules by an enzyme.
Irreversible reactions
A metabolic pathway where a product molecule can’t be converted back into its substrate by an enzyme.
Alternative reactions
Metabolic pathways with a different substrate, and a different enzyme, however the same product is formed.
Types of enzyme reactions (metabolic pathway)
Catabolic and anabolic
Anabolic reactions definition
An enzyme controlled reaction which build up substrate molecules into larger product molecules requiring energy, in the active site.
Catabolic reactions definition
An enzyme controlled reaction which breaks down the substrates into smaller product molecules releasing energy in the active site.
Enzymes definition
Enzymes are biological catalysts made of protein by a living cell, meaning they speed up the rate of reaction without being used up by decreasing the activation energy.
Enzymes type of protein
Globular
Activation energy definition
The energy required for substrates to form products
Rules of activation energy in relation to speed of reaction
The lower the activation energy the faster the reaction.
High affinity
Where there is a strong attraction between the substrate and the enzyme.
Low affinity
Where the active site and the product repel each other.
Rules of affinity of enzymes
Low affinity of products
High affinity of substrates
Induced fit
Where an enzymes active site changes shape to suit the shape of the substrate after it has bound to the active site.
Inhibition definition
Where an enzyme cannot change the shape of a substrate, due to the presence of another molecule.
Inhibition definition
Where an enzyme cannot change the shape of a substrate, due to the presence of another molecule.
Types of inhibition
Competitive, non competitive, feedback.
Competitive inhibitor definition
A molecule which binds to the active site of an enzyme and prevents the enzyme from changing the substrates shape.
Competitive inhibitor definition
A molecule which binds to the active site of an enzyme and prevents a substrate from entering or binding with the enzyme’s active site, therefore preventing the substrate from being catalysed.
Rules of competitive inhibition
As the concentration of substrate increases the rate of reaction increases, due to there being a higher chance of a substrate binding to the active site.
As the concentration of inhibitor increases the rate of reaction decreases due to there being a higher chance of the inhibitor binding to the enzymes active site.
Non competitive inhibitors
molecules which bind to the allosteric site, which changes the shape of the active site, to prevent the substrate from binding with the active site.
Rules of non competitive inhibitors
As the substrate concentration increases the rate of reaction stays constant, since the non competitive inhibitor changes the shape of the enzymes active site, preventing the chance of the substrate binding with the enzymes active site.
Rules of non competitive inhibitors
As the substrate concentration increases the rate of reaction stays constant, since the non competitive inhibitor changes the shape of the enzymes active site, preventing the chance of the substrate binding with the enzymes active site.
Feedback inhibitors
End product molecules, that when there is a critical concentration of the molecule, the molecule will bind with the allosteric site, in an enzyme earlier on in the process, to stop the production of the product.
Types of proteins in membrane
Pores pumps and enzymes
