Energy & Metabolism 2 Flashcards
What are the characteristics of an enzyme
- complexity
- efficiency
- specificity
- require co-enzymes or co-factors
- subject to activation or inhibition
Explain complexity of an enzyme
proteins with complex 3D structures
Explain efficiency of an enzyme
- reduce activation energy
- occurs with high speed
Explain specificity of an enzyme
- many catalyse only one type of reaction
- has an ‘active site’ where only certain substrates can bind
- lock & key model
- induced fit model
Explain co-enzymes & co-factors
co-enzymes: organic molecules derived from vitamins
co-factors: can be metal ions or trace elements
Explain ‘subject to activation’ in enzyme reactions
enzymes stored as inactive form, then activated when needed
Explain ‘subject to inhibition’ in enzyme reactions
- allows precise regulation
- mode of action of different drugs and poisons
What is enzyme concentration?
as enzyme concentration increases, reaction rate increases
What is substrate concentration?
as substrate concentration increases, reaction rate increases but only to saturation point
how does temperature effect enzyme reactions?
increased temperature = increased reaction rates which lead to more collisions of molecules
how does pH effect enzyme reactions?
- each enzyme has an optimum pH range
- if outside range denaturing will occur
- helps control when reaction will take place
Explain enzyme importance
- optimum body functions depend on optimum enzyme function
- DNA codes for enzymes
Define energy
ability to do ‘work’
the greater the work done, the more energy expended
Define the chemical form of energy & an example in the body
Definition: stored in chemical bonds between atoms
Example: energy value of food
Define the thermal form of energy & an example in the body
Definition: form which releases heat
Example: temperature homeostasis
