Chapter 3: Enzymes Flashcards
(52 cards)
How to measure the initial rate of reaction?
- Where does it look most linear?
- Find the (x,y)
- Slope = (change in y/change in x)
- Example: x=10, y=6
- (6-0/10-0)
- 6/10
- initial rate of reaction 0.6 mol
Explain the effect of enzyme concentration on enzyme activity.
As enzyme concentration increases, the initial rate of reaction increases.
Why does the initial rate of reaction increase as enzyme concentration increases?
More enzymes = more active sites
More active sites = more places for substrate molecules to bind to
More substrate molecules bound to active sites = more product produced quicker
Explain the effect of substrate concentration on enzyme activity.
As substrate concentration increases, reaction rate will increase but only to a point.
point of enzyme-saturation
all active sites are engaged
How to determine velocity
The rate at which the active site can convert SUBSTRATE —-> PRODUCT
Explain the effect of temperature on enzyme activity.
As temperature increases, reaction rate will increase but only to a point. Once the temperature exceeds the optimal temperature for enzyme activity, reaction rate will decrease.
What is the optimal temperature for most human enzymes?
35-40*C
What happens to enzymes and substrates when temperature increases ?
They move faster, making it more likely for them to collide with one another
What happens if the temperature gets too high?
The enzyme vibrates SO rapidly that they denature. This DESTROYS the active site
Denature
Loses their tertiary shape
What happens when all the enzymes have denatured?
The reaction stops
What happens to enzymes during cold temperatures?
They do not denature they just move slowly
Explain the effect of pH on Enzyme activity.
As pH decreases or increases from the optimum, reaction rate will decrease.
The optimal pH of most human enzymes
pH 6-8
When do enzymes denature from pH.
acidic or basic conditions denature most enzymes
Explain the effect of inhibitors on enzyme activity.
inhibitors are molecules that interfere with the normal functioning of enzymes and slow down or stop enzyme activity
What are the two main types of inhibitors.
competitive and noncompetitive
What are competitive inhibitors
They are similar to enzyme’s substrate and binds to the active site.
•similar to enzyme
•binds to active site
What are noncompetitive inhibitors
They are not similar to the enzyme’s substrate and do not bind to the active site
•not similar to substrate
•do not bind to active site
Where do noncompetitive inhibitors bind to?
an alternative site
What do noncompetitive inhibitors do to the enzyme when they bind to the alternative site
They alter the shape of the active site and the substrate can’t bind to it
What happens when you increase the concentration of an inhibitor?
the rate of reaction reduces and the reaction can completely stop at very high concentrations of inhibitors
