Metabolism and Enzymes Flashcards
Anabolic reaction
Build up large molecules from small molecules
Catabolic
Break down large molecules
Enzymes
3D proteins that have depressions or active sites that catalyse specific chemical reactions without them themselves being altered
Features of enzymes (9)
Proteins, Speed up chemical reactions, Not used up in the reaction, Reaction specific, Work under specific conditions, Work by lowering the energy of the reaction, Work on lock-and-key principle, Often work with co-enzymes and co-factors, Can be denatured by heating
Activation energy
Energy needed to start a chemical reaction
How enzymes work with activation energy
Usually heat provides activation energy but not viable in living organisms, Enzymes lower the activation energy of reactions they catalyse
Lock-key model
Analogy put forward to explain the specific action of an enzyme with a single substrate
Catabolic enzymes
Enzymes weaken chemical bond resulting in the substrate breaking down into 2 smaller molecules
Anabolic enzyme
Enzyme facilitates the formation of bonds between the substrate molecules producing a larger molecule
Co-factors and Co-enzymes
Small non-protein molecules that enhance enzyme function by making sure the active site is the right shape
Co-factors
Inorganic such as metal ions
Co-enzymes
Organic co-factors
Example of a Co-factor
DNA polymerase
Inhibitors
Molecules that interfere with the enzyme in some way
Competitive inhibitor
Has a similar shape to the substrate, Binds on the active site and blocks the substrate from binding so prevents the formation of the enzyme substrate complex
Non-competitive inhibitor
Inhibitor binds to another part of the enzyme and changes the shape in such a way to prevent the enzyme product complex forming
Example of a competitive inhibitor
Cyanide
Example of non-competitive inhibitor
Strychnine
Factors that affect enzyme activity
Temperature, Ph, Enzyme concentration, Co-factors
Effect of high temperature outside optimal range of enzymes (6)
Enzyme active site denatures, Chemical bonds holding the active site together break, active site changes shape, active site can no longer bind with the substrate, enzyme activity decreases or stops, no products form
As enzyme concentration increases
rate of reaction increases assuming there is a sufficient substrate
As substrate concentration increases
Increases reaction rate initially but then the enzyme site becomes saturated
