VET272 - Prac Exam 2023/2024 questions and answers
complete
Measurement of alkaline phosphate in plasma (blood) can be used for diagnosis
of bone and liver diseases.
True or False
True
Which pipette is most appropriate for measuring 0.1mL?
a) P20
b) P200
c) P1000
d) P5000
b) P200
Which pipette is most appropriate for measuring 0.1mL?
a) P20
b) P200
c) P1000
d) P5000
b) P200
Why is a buffer used in the assays?
a) The buffer provides substrate from the reaction.
b) The buffer causes a colour change that can be measured using the
spectrophotometer.
c) The buffer is used to maintain a constant pH throughout the assay.
d) The buffer is added to the tubes to destroy the enzyme and terminate the
reaction.
c) The buffer is used to maintain a constant pH throughout the assay.
Define Km
The concentration of substrate which enables the enzyme to work at half its maximal
velocity
Define Vmax
The max velocity that is reached when an enzyme is saturated with substrate
Define what is meant by specific activity.
Activity expressed relative to a fixed value such as weight of tissue or volume of fluid
Alkaline phosphatase is a constitutive enzyme and so factors such as
temperature, pH, substrate concentration, and inhibitors will affect its activity.
True or False
True
,The enzyme extract should be kept on ice at all times to minimise loss of activity.
True or False
True
Which of the following actions will cause results to be inaccurate?
a) Not mixing assay samples correctly using the vortex
b) Using incorrect kidney homogenate concentration
c) Reading the samples in the spectrophotometer using the wrong wavelength
d) All of the above
d) All of the above
When using an enzymatic method for measuring the concentration of a
substance in blood or tissue extract, inhibitors should be?
a) limiting
b) non-limiting
c) inhibitors should not be included
c) inhibitors should not be included
When using an enzymatic method for measuring the concentration of a
substance in blood or tissue extract, incubation time should be?
a) relatively long (reaction complete)
b) relatively short (reaction incomplete)
c) reaction time will not affect the assay
a) relatively long (reaction complete)
An enzymatic method for measuring the concentration of a substance in blood or
tissue extract should be run under?
a) zero order kinetics (substrate saturation)
b) first order kinetics (substrate limiting)
c) terminal velocity
a) zero order kinetics (substrate saturation)
Which of the following combinations BEST completes the blanks in the following
statement:
The graph of the amount of product formed versus time shows the progress
curve of the reaction. In general, a progress curve has the maximum slope
_________ and over time the the slope starts to _____________ .
a) soon after the start of the reaction; level out
b) a long time after the reaction has started; level out
c) soon after the start of the reaction; increase
d) a long time after the reaction has started; increase
a) soon after the start of the reaction; level out
If a assay is run under zero order kinetics (substrate not limiting), then what is the
effect of doubling the concentration of the enzyme on the amount or product
produced?
, a. The amount of product produced will double
b. The amount of product produced will halve
c. There will be no change in the amount of product produced
a. the amount of product produced will double
If a assay is run under zero order kinetics (substrate not limiting), then what is the
effect of doubling the concentration of the enzyme on the enzyme specific
activity?
a. Specific activity will double
b. Specific activity will halve
c. Specific activity will remain constant
c. Specific activity will remain constant
In an enzyme assay measuring enzyme activity, substrate concentration should
be:
a. Limiting
b. Non-limiting
c. Substrate concentration doesn't matter to the assay
b. Non-limiting
In an enzyme assay measuring enzyme activity, enzyme concentration should be:
a. Limiting
b. Non-limiting
c. Enzyme concentration does not affect the assay
a. limiting
In an enzyme assay measuring enzyme activity, the concentration of co-factors
should be:
a. Limiting
b. Non-limiting
c. Co-factor concentration does not affect the assay
b. non-limiting
In an assay measuring enzyme activity, inhibitors should be:
a. Limiting
b. Non-limiting
c. not be included
c. not be included
In an assay measuring enzyme activity, the incubation time should be:
a. Relatively short (reaction incomplete)
b. Relatively long (reaction complete)
c. Reaction time will not affect the assay
a. relatively short (reaction incomplete)
complete
Measurement of alkaline phosphate in plasma (blood) can be used for diagnosis
of bone and liver diseases.
True or False
True
Which pipette is most appropriate for measuring 0.1mL?
a) P20
b) P200
c) P1000
d) P5000
b) P200
Which pipette is most appropriate for measuring 0.1mL?
a) P20
b) P200
c) P1000
d) P5000
b) P200
Why is a buffer used in the assays?
a) The buffer provides substrate from the reaction.
b) The buffer causes a colour change that can be measured using the
spectrophotometer.
c) The buffer is used to maintain a constant pH throughout the assay.
d) The buffer is added to the tubes to destroy the enzyme and terminate the
reaction.
c) The buffer is used to maintain a constant pH throughout the assay.
Define Km
The concentration of substrate which enables the enzyme to work at half its maximal
velocity
Define Vmax
The max velocity that is reached when an enzyme is saturated with substrate
Define what is meant by specific activity.
Activity expressed relative to a fixed value such as weight of tissue or volume of fluid
Alkaline phosphatase is a constitutive enzyme and so factors such as
temperature, pH, substrate concentration, and inhibitors will affect its activity.
True or False
True
,The enzyme extract should be kept on ice at all times to minimise loss of activity.
True or False
True
Which of the following actions will cause results to be inaccurate?
a) Not mixing assay samples correctly using the vortex
b) Using incorrect kidney homogenate concentration
c) Reading the samples in the spectrophotometer using the wrong wavelength
d) All of the above
d) All of the above
When using an enzymatic method for measuring the concentration of a
substance in blood or tissue extract, inhibitors should be?
a) limiting
b) non-limiting
c) inhibitors should not be included
c) inhibitors should not be included
When using an enzymatic method for measuring the concentration of a
substance in blood or tissue extract, incubation time should be?
a) relatively long (reaction complete)
b) relatively short (reaction incomplete)
c) reaction time will not affect the assay
a) relatively long (reaction complete)
An enzymatic method for measuring the concentration of a substance in blood or
tissue extract should be run under?
a) zero order kinetics (substrate saturation)
b) first order kinetics (substrate limiting)
c) terminal velocity
a) zero order kinetics (substrate saturation)
Which of the following combinations BEST completes the blanks in the following
statement:
The graph of the amount of product formed versus time shows the progress
curve of the reaction. In general, a progress curve has the maximum slope
_________ and over time the the slope starts to _____________ .
a) soon after the start of the reaction; level out
b) a long time after the reaction has started; level out
c) soon after the start of the reaction; increase
d) a long time after the reaction has started; increase
a) soon after the start of the reaction; level out
If a assay is run under zero order kinetics (substrate not limiting), then what is the
effect of doubling the concentration of the enzyme on the amount or product
produced?
, a. The amount of product produced will double
b. The amount of product produced will halve
c. There will be no change in the amount of product produced
a. the amount of product produced will double
If a assay is run under zero order kinetics (substrate not limiting), then what is the
effect of doubling the concentration of the enzyme on the enzyme specific
activity?
a. Specific activity will double
b. Specific activity will halve
c. Specific activity will remain constant
c. Specific activity will remain constant
In an enzyme assay measuring enzyme activity, substrate concentration should
be:
a. Limiting
b. Non-limiting
c. Substrate concentration doesn't matter to the assay
b. Non-limiting
In an enzyme assay measuring enzyme activity, enzyme concentration should be:
a. Limiting
b. Non-limiting
c. Enzyme concentration does not affect the assay
a. limiting
In an enzyme assay measuring enzyme activity, the concentration of co-factors
should be:
a. Limiting
b. Non-limiting
c. Co-factor concentration does not affect the assay
b. non-limiting
In an assay measuring enzyme activity, inhibitors should be:
a. Limiting
b. Non-limiting
c. not be included
c. not be included
In an assay measuring enzyme activity, the incubation time should be:
a. Relatively short (reaction incomplete)
b. Relatively long (reaction complete)
c. Reaction time will not affect the assay
a. relatively short (reaction incomplete)
