2.4 Enzymes Flashcards
What is the difference between a catabolic and an anabolic pathway?
Catabolic- metabolites broken down to smaller ones, releasing energy
Anabolic- energys used to synthesize larger molecules from smaller ones
What is a co factor?
A substance that has to be present to ensure an enzyme catalysted reaction takes place at the appropriate rate. Some are part of the enzymes structure, others (mineral ion cofactors and organic coenzymes) form temporary associations with the enzymes
What is the lock and key hypothesis
Substrate fits in enzyme way key fits in lock
What is the induced fit hypothesis
Substrate changes shape of active site
What is the name of amount of energy needed to start a reaction?
Activation energy
Do enzymes increase or reduce activation energy required for a reaction?
Reduce
How does temperature effect enzyme activity? 2
Kinetic energy- mols move faster, increase rate of successful collision
increasing beyond optimum reduces rate of reaction as breaks hydrogen bonds, hold tertiary structure, denture enzyme, not complimentary to substrate
What is the optimum temperature and what happened to the rate of reaction at this temperature?
The temperature at which the enzyme works at its fastest rate
The rate of reaction is at its maximum
What is Q10?
Temperature coefficient -
Rate of reaction at (T+10)/ Rate of reaction at T
What is the effect of pH on enzyme activity?
Increased pH interferes with hydrogen bonds, change tertiary structure, chance active site, not complimentary to substrate, rate of reaction decreases
What is a buffer?
Resists changes in pH
Can donate/accept hydrogen ions
Enzymes work within a narrow range of pH. What does this mean for the rate of reaction and change of pH?
Small changes in pH will slow the rate of reaction
What is the effect of substrate concentration on enzyme-catalysed reactions? (6)
1 Increases because more ESCs can form
2 more product forms
3 substrate conc is limiting factor because as it increases the RofR increases
4 if substrate conc increases further, reaction reaches maximum rate, adding more substrate will not ii crease RofR
5 because enzymes are fully saturated/ active sites are fully occupied with substrate
6 so no additional substrate can successfully collide with active site
What is the effect of enzyme concentration on RofR
1 more active sites available
2 more successful collisions occur between enzyme and substrate
3 more ES complexes
4 enzyme conc is limitimg factor, as it increases, so does r of r
5 if increased further, no increase r of r because active sites of extra enzymes won’t be occupied
6 sub is now limiting factor
What are the two types of enzyme inhibition?
Competitive
Non competitive
