Font size
WorksheetsPOP QUIZ CHAPTER 4- BIOCATALYSIS
Total questions: 40
Worksheet time: 34mins
Enzyme affect the speed of chemical reaction without being consumed, they are referred to as
hydrogen acceptor
activation energy
biocatalyst
cytochrome
Enzymes are important biological catalysts because they:
supply the energy to initiate a biochemical reaction
increase the free energy of a biochemical reaction
lower the entropy and enthalpy of a biochemical reaction
lower the activation energy of a biochemical reaction
Most enzyme are ___________
carbohydrate
lipid
protein
DNA
The line on the graph labeled A represents the:
activation energy with an enzyme
activation energy without an enzyme
free energy of the reactants
change in entropy and enthalpy
Parts of the enzyme molecule that interact with a substrate are called:
cofactors
active sites
induced-fit models
reaction sites
Which of the following is true of enzymes?
Enzymes may require a non-protein cofactor or ion for catalysis to take place
Enzyme function is influenced by physical and chemical environmental factors such as pH and temperature
Enzymes increase the rate of chemical reaction by lowering activation energy
All of these are correct
Only a small amount of enzyme is needed for a large amount of substrate because _______
Enzymes do not change at the end of a reaction and as such can be reused
A small amount of enzyme can provide enough energy to continue the reaction
More enzymes are formed while reaction takes place
Enzymes act till completion of a reaction or not at all
Which of the following match with the characteristics of enzyme that the bonds are broken down and cause enzyme is not function anymore
will denature in high pH and temperature
enzyme is highly specific
will denature in extreme pH & very high temperature
enzyme is reusable
Enzyme that catalyses the transfer of functional group of atoms from one molecule to another. This enzyme is
Isomerases
Transferases
Oxidoreductase
Lyases
Enzymes in group Isomerases catalyse
the rearrangement of atoms
the transfer of functional group of atoms
the breaking of chemical bond
the formation of bonds
What is structure C?
Substrate-enzyme complex
Substrate-enzyme complement
Enzyme-substrate complement
Enzyme-substrate complex
Which of the following statements regarding enzyme is TRUE
Enzyme decreases the free energy change of a reaction
Enzyme changes the direction of chemical reaction
Enzyme increase rate of reaction
Enzyme prevents changes in substrate concentration
Watch the animation and identify the hypothesis involved
Lock and Key hypothesis
Induced Fit hypothesis
Enzyme-Substrate hypothesis
Which of the following does not affect enzyme activity?
temperature
pH
substrate concentration
sugar
What will happen when enzyme is denatured?
A proton is added or removed from the enzyme.
It reaches its temperature at which it exhibits maximum activity.
A substance binds to it which slows or stops its normal catalytic function.
It changes shape and the active site no longer matches the shape of the substrate molecule.
This graph shows the enzyme activity when substrate concentration is increased. What is the reason of this enzyme activity pattern?
There is no available substrate.
The active site changes its shape, thus, preventing the substrate from binding.
High substrate concentration affects the temperature at which enzymes work best.
Enzymes are all occupied, the incoming substrate molecules must wait for an active empty site.
Why an increased in temperature (up to the optimum temperature) increases the enzyme reaction?
Because kinetic energy of molecules decreases.
Because kinetic energy of molecules increases.
Because denaturation of enzymes occurs.
Because inhibitors are eliminated at this condition.
Competitive inhibition can be overcome by _______________
increase the concentration of substrate
reduce the concentration of enzyme
increase the concentration of enzyme
reduce the concentration of substrate
If one continues to increase the temperature in an enzyme-catalyzed reaction, the rate of the reaction:
increases and then levels off
decreases and then levels off
increases and then decreases rapidly
decreases and then increases rapidly
Select the name of the mechanism of the binding of a substrate to the active site of enzyme which is the active site is flexible.
active site
cofactor
activation energy
Induced fit
Consider the following: “Succinate dehydrogenase catalyzes the conversion of succinate to fumarate. The reaction is inhibited by malonic acid, which resembles succinate but cannot be acted upon by succinate dehydrogenase. Increasing the ratio of succinate to malonic acid reduces the inhibitory effect of malonic acid”.
Which of the following is correct?
Succinate dehydrogenase is the enzyme, and fumarate is the substrate
Succinate dehydrogenase is the enzyme, and malonic acid is the substrate
Succinate is the substrate, and fumarate is the product
Fumarate is the substrate, and malonic acid is a non-competitive inhibitor
What is an organic non-protein "helper" of an enzyme molecule called?
accessory enzyme
allosteric group
cofactor
functional group
Which of the following is true of enzymes?
Enzymes may require a non-protein cofactor or ion for catalysis to take place
Enzyme function is influenced by physical and chemical environmental factors such as pH and temperature
Enzymes increase the rate of chemical reaction by lowering activation energy
All of these are correct
In which way the enzymatic reaction can be increased if the enzymes are saturated with the substrate?
add more enzymes
add more substrate
increase the temperature
add cofactor
How does enzyme lower the activation energy?
Bring substrate closer to each other
Increase the kinetic energy of substrate
Weakening the bonds inside the substrate
Bring substrate together into correct orientation
what reduces the productivity of enzymes by blocking substrates from entering active sites?
non competitive inhibitors
competitive inhibitors
coenzymes
cofactors
Which of the following are the properties of enzyme?
I Enzymes are highly specific.
II All enzymes are denatured at 60°c
III A large number of enzymes is needed to react with large number of substrate.
IV Enzymes lower the activation energy.
I only.
I and IV only.
I, II and III
I, II and IV
The protein part of an enzyme that binds to prosthetic group to form a functional enzyme is called
holoenzyme
apoenzyme
coenzyme
conjugated protein
Which of these statements are true about competitive inhibitor?
Inhibitor and substrate has similar structure
The inhibitor binds to the allosteric site
The conformation of active site changed due to the inhibitor
Quantity of product formed is the same as reaction with no inhibitor
When a molecule can occupy the same active site as the substrate, a situation called __________________ can result
Competitive lnhibition
Allosteric Regulation
Non-Competitive Inhibition
Feedback Inhibition
A receptor site that a molecule can bind to that changes the shape of the active site is called a(n):
Allosteric Site
Active Site
DiSulphide Bridge
MHC Receptor
Molecules that bind to enzymes and enhance an enzyme's ability are called:
CoFactors
CoEnzymes
Allosteric Inhibitors
Allosteric Activators
Organic molecules that temporarily bind to enzymes and enhance an enzyme's ability are called:
CoFactors
CoEnzymes
Allosteric Inhibitors
Allosteric Activators
When an enzyme tightens around a substrate, this is called:
An awkward hug
Induced fit
Competitive Inhibition
Non competitive Inhibition
What's going on in this picture?
The enzyme is taking the red substrate and turning it blue
The enzyme's active site is blocked by a competitive inhibitor
The enzyme can't function if too many substrates are trying to bind
This is an example of an anabolic enzyme reaction
Which is true of non-competitive inhibition?
It is irreversible
The inhibitor binds only to the active site of enzyme
The inhibitor binds to enzyme to lower activation energy
It can be reduced by increasing the concentration of the substrate
Which type of reversible enzyme inhibitor binds to both the free enzyme and the enzyme-substrate complex?
Non-competitive inhibitor
End product inhibitor
Competitive inhibitor
None of the above
Describe the effect of temperature as it increase
kinetic energy of substrate and enzyme increased
rate of reaction is maximum
collision between substrate and enzyme's active site increased
