Enzyme Kinetics Flashcards
How do enzymes alter a reaction rate?
Lower the activation energy of a reaction.
PLant cell walls are made of a variety of polysaccharides and other compounds, but the primary component is ____.
Cellulose
What is the enzyme that we are measuring the activity of in today’s lab?
Cellobiase
What is the compound that we will use to detect as a measure of enzyme activity?
p-nitrophenol
What is the artificial substrate used to detect enzymatic activity of cellobiase?
p-nitrophenyl glucopyranoside
What is the chemical reaction that the artificial substrate undergoes to from the yellow product that is detected as enzymatic activity?
Endocellulase
Exocellulase
Cellobiase
What is the function of the stop solution?
It used to stop the solution from continuing the enzymatic activity.
What are the two types of cellulases?
endocellulase
exocellulase
What were the 2 main objective of this lab?
1- Measure the enzymatic activity of cellobiase; and
2- Identify the optimal conditions for the enzyme
The reactant in an enzyme-catalyzed reaction is called the ______.
substrate
Once the activation energy is lowered, the chemical reaction occurs at a much ______ rate.
faster
What can affect the enzymes’ effectiveness?
Changes in salinity
Changes in pH
Temperature change
Relative concentration of all molecules
When an enzyme changes shape, it is said to be ______.
denatured
Most enzymes function best at _______.
moderate temperatures (20C-40C)
What is V_max?
Maximum rate at which the product can be produced given a particular enzyme and raw materials.
_______ catalyze the cellulose to glucose.
Cellulase
Humans and other animals produce cellulase. True or False?
False
What three tasks must be completed to produce ethanol from plant matter?
- Pretreatment;
- Enzymatic hydrolysis;
- Microbial fermentation
Cellulose is broken down into glucose in the following 3 steps by 3 different enzymes. Which are they?
Endocellulases
Exocellulases
Cellobiases
Which enzyme break down the internal bonds of the long chains of glucose molecules that form cellulose?
Endocellulase
Which enzyme break the covalent linkage between the glucose units of cellulose that are on the end of the cellulose molecules, releasing cellobiase?
Exocellulase
Which enzyme breaks down the cellobiose left behind as a result of the work of the first 2 enzymes?
Cellobiase (B-glucosidase)
What is the preferred source of sugar for microbial fermentation?
Glucose
What instrument measures the amount of light absorbed by the sample?
Spectrophotometer
At what wavelength does the spectrophotometer measure the amount of yellowness of an enzyme?
410 nm
The darker the color of yellow a sample, the ____ concentrated the sample.
more
What is the constant K_m?
Michaelis constant
What does Km describe?
The efficiency of the conversion of substrate to product
An enzyme can work at its maximum rate when its active sites are ____ saturated with substrate.
completely
What is the Michaelis-Menten equation?
V_o=(V_max * [S]) / (K_m + [S])
What is the Michaelis-Menten equation used for?
To predict the rate of product formation in enzymatic reactions
What is the Lineweaver-Burk plot?
- A double-reciprocal line graph that plots (1/V_o) as a function of (1/[S]).
- It is used to determine important terms in enzyme kinetics such as K_m and V_max
The dissociation constant for the enzyme-substrate is _____.
K_m
The greater the value K_m, the ___ tightly the substrate is bound to the enzyme.
less
The less the value K_m, the ___ tightly the substrate is bound to the enzyme.
more
