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WorksheetsBiocatalysis
Total questions: 20
Worksheet time: 15mins
Watch the animation and identify the hypothesis involved
Lock and Key hypothesis
Induced Fit hypothesis
Enzyme-Substrate hypothesis
Zinc, an essential trace element for most organisms, is present in the active site of enzyme carboxypeptidase. The zinc most likely functions as_______.
a coenzyme derived from a vitamin
a non-competitive inhibitor of the enzyme
a competitive inhibitor of the enzyme
a cofactor necessary for enzyme activity
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 rate of reaction of salivary amylase on starch decreases when the concentration of chloride ion is reduced. Which of the following explains the role of a chloride ion?
active site
substrate
cofactor
inhibitor
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
In which way the enzymatic reaction can be increased if the enzymes are saturated with the substrate?
add more substrate
add more enzymes
add cofactor
increase the temperature
The active site of an enzyme is the region that _________
binds allosteric regulators of the enzyme
is involved in the catalytic reaction of the enzyme
binds the product of the catalytic reaction
is inhibited by the presence of a coenzyme or a cofactor
Which of these statements regarding enzymes is false?
Enzymes are proteins that function as catalysts
Enzymes display specificity for certain molecules with which they interact
Enzymes increase the activation energy for the reactions they catalyze
The activity of enzymes can be regulated by other molecule
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 malonic acid is the substrate
Succinate is the substrate, and fumarate is the product
Succinate dehydrogenase is the enzyme, and fumarate is the substrate
Fumarate is the substrate, and malonic acid is a non-competitive inhibitor
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
Give one similarities between competitive inhibitor and non-competitive inhibitor action is ________________.
The maximum rate of reaction is not reached
Rate of reaction can be increased by increasing the substrate concentration
Both caused enzyme's conformation changed
Reaction become slower
Which of these statements are true about non-competitive inhibitor?
Inhibitor and substrate has similar structure
The inhibitor binds to the allosteric site
The conformation of active site remain unchanged due to the inhibitor
Quantity of product formed is the same as reaction with no inhibitor
Based on the graph shown above
i. Enzymes are denatured
ii. Enzyme's active site are fully occupied with substrate
iii. Active site of enzyme is no longer complementary with substrate
iv. The rate of reaction increases with increasing substrate concentration
i and ii
i and iii
ii and iii
ii and iv
State the function of X?
Binding site of substrate
Binding site of cofactor
Binding site of reactant
Binding site of inhibitor
Which of the following conclusions can be drawn from this graph?
The optimum pH of the enzyme is 5.8
The optimum pH of the enzyme is 6.6.
The enzyme’s activity increases as pH increases 5.0 to 9.0
The enzyme’s activity is greater around pH of 8.0 .
Which of the following is TRUE about 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
When end product acts as inhibitor by combining to initial enzymes, it is called as ________
Induced fit
irreversible inhibitor
feedback inhibition
reversible inhibitor
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
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
What is structure C?
Substrate-enzyme complex
Substrate-enzyme complement
Enzyme-substrate complement
Enzyme-substrate complex
