2.1.4 Enzymes Flashcards
1
Q
what is an example of an intracellular enzyme?
A
- catalase
- works inside cell
- catalyses breakdown of hydrogen peroxide
2
Q
what’s an example of an extracellular enzyme?
A
- amylase
- works outside cells in digestive system
- catalyses hydrolysis of starch into maltose
3
Q
what do enzymes do to activation energy?
A
reduce it
4
Q
what is activation energy?
A
certain amount of energy needed for a reaction to occur
5
Q
how do enzymes lower activation energy?
A
- formation of an enzyme substrate complex
- if two substrate molecules need to join, attaching to enzyme holds them together reducing repulsion
- if enzyme is catalysing breakdown reaction, fitting into active site creates a strain in substrate bonds. bonds break up more easily
6
Q
what does the induced fit model say about enzymes?
A
as substrate binds, active site changes shape slightly to fit substrate more easily
7
Q
what factors affect enzyme activity?
A
- temp
- ph
- substrate conc
- enzyme conc
8
Q
how does temp affect enzyme activity?
A
- more kinetic energy so substrates move faster and more collisions so more enzyme substrate complex formed
- if temp goes above certain level, vibration breaks bonds in enzyme, active site changes shape and substrate no longer fits
9
Q
what is the temperature coefficient (Q10)?
A
how much the rate of reaction changes when temp is raised by 10°C
10
Q
how does ph affect enzyme activity?
A
- too low or too high ph messes up hydrogen and ionic bonds in tertiary structure
- done by H+ and OH- ions
11
Q
how does enzyme concentration affect enzyme activity?
A
- more enzyme molecules = more likely for a substrate to collide and bind to form an enzyme substrate complex
- ** if more enzyme than substrates**, all substrates will be used up so increasing conc will then have no effect
12
Q
how does substrate concentration affect enzyme activity?
A
- higher chance of collision and enzyme substrate complexes forming
- more active sites used up
- after saturation point, all active sites full so increase conc will not increase rate of reaction
