WGU C785 Biochemistry Unit Exam Questions &
Answers Latest 2024/2025 with complete solution
Which type of inhibition occurs when a particular drug binds to the active site of
an enzyme?
Competitive
Uncompetitive
Irreversible
Noncompetitive - -answer-Competitive
Competitive inhibitors compete with the substrate to bind to the active site of the
enzyme.
Salivary amylase, an enzyme responsible for partial digestion of carbohydrates,
has optimum activity at a pH value of 6.8.
What is the impact on the activity if the pH is decreased to 4.0?
,Significantly increase
Significantly decrease
Slightly decrease
Slightly increase - -answer-Significantly decrease
A drop in pH from 6.8 to 4.0 is a significant change in pH. Recall that the hydrogen
bonds and ionic bonds that hold protein structures together can be broken by
changes in pH. The disruption in protein structure due to this pH change will also
significantly decrease amylase activity.
Low levels of glutathione are associated with certain types of ovarian and breast
cancers. In the synthesis of glutathione, glutathione accumulates in the cell,
binding to an enzyme in the pathway and temporarily preventing the synthesis of
glutathione. Which type of inhibition is described by this scenario?
Feedback
Competitive
Allosteric
Uncompetitive - -answer-Feedback
,The keywords here are that glutathione accumulates and binds to an enzyme in
the pathway to prevent synthesis. Feedback inhibition occurs when a product of a
pathway turns into an inhibitor of an enzyme earlier in the pathway.
Lipase is an enzyme with an optimum temperature of 98.6°F and an optimum pH
of 7.0 in the duodenum in the human body. If a person is experiencing a fever of
99.8°F, what will increase the activity of the lipase enzyme?
Decrease in temperature
Increase in temperature
Decrease of the substrate of the enzyme
Increase of pH of duodenum to 8.0 - -answer-Decrease in temperature
An enzyme will have the highest activity when it is under optimal conditions. In
this case, the fever of 99.8 is above the optimal temperature, so lowering the
temperature will increase activity.
The enzyme glucokinase only binds its substrate glucose and converts glucose into
the product glucose-6-phosphate. Which property of enzymes is described by this
scenario?
Specificity
, Activation energy
Induced fit
Reaction rate - -answer-Specificity
Enzymes have a high degree of specificity. They will bind to one specific class of
molecules and usually catalyze only one type of reaction.
Low levels of glutathione are associated with neurological, immunological, and
cardiovascular impairments. Two enzymatic reactions are involved in the
synthesis of glutathione. In the second enzymatic reaction, glutathione synthetase
converts glycine to glutathione. What would potentially decrease risks associated
with low levels of glutathione?
Increasing the amount of glycine in the diet
Noncompetitive inhibitor of glutathione synthetase
Uncompetitive inhibitor of glutathione synthetase
Decreasing the amount of glycine in the diet - -answer-Increasing the amount of
glycine in the diet
One way to increase glutathione levels is to increase the activity of glutathione
synthetase. Glutathione synthetase activity can be increased by increasing the
amount of substrate, or glycine available.
Answers Latest 2024/2025 with complete solution
Which type of inhibition occurs when a particular drug binds to the active site of
an enzyme?
Competitive
Uncompetitive
Irreversible
Noncompetitive - -answer-Competitive
Competitive inhibitors compete with the substrate to bind to the active site of the
enzyme.
Salivary amylase, an enzyme responsible for partial digestion of carbohydrates,
has optimum activity at a pH value of 6.8.
What is the impact on the activity if the pH is decreased to 4.0?
,Significantly increase
Significantly decrease
Slightly decrease
Slightly increase - -answer-Significantly decrease
A drop in pH from 6.8 to 4.0 is a significant change in pH. Recall that the hydrogen
bonds and ionic bonds that hold protein structures together can be broken by
changes in pH. The disruption in protein structure due to this pH change will also
significantly decrease amylase activity.
Low levels of glutathione are associated with certain types of ovarian and breast
cancers. In the synthesis of glutathione, glutathione accumulates in the cell,
binding to an enzyme in the pathway and temporarily preventing the synthesis of
glutathione. Which type of inhibition is described by this scenario?
Feedback
Competitive
Allosteric
Uncompetitive - -answer-Feedback
,The keywords here are that glutathione accumulates and binds to an enzyme in
the pathway to prevent synthesis. Feedback inhibition occurs when a product of a
pathway turns into an inhibitor of an enzyme earlier in the pathway.
Lipase is an enzyme with an optimum temperature of 98.6°F and an optimum pH
of 7.0 in the duodenum in the human body. If a person is experiencing a fever of
99.8°F, what will increase the activity of the lipase enzyme?
Decrease in temperature
Increase in temperature
Decrease of the substrate of the enzyme
Increase of pH of duodenum to 8.0 - -answer-Decrease in temperature
An enzyme will have the highest activity when it is under optimal conditions. In
this case, the fever of 99.8 is above the optimal temperature, so lowering the
temperature will increase activity.
The enzyme glucokinase only binds its substrate glucose and converts glucose into
the product glucose-6-phosphate. Which property of enzymes is described by this
scenario?
Specificity
, Activation energy
Induced fit
Reaction rate - -answer-Specificity
Enzymes have a high degree of specificity. They will bind to one specific class of
molecules and usually catalyze only one type of reaction.
Low levels of glutathione are associated with neurological, immunological, and
cardiovascular impairments. Two enzymatic reactions are involved in the
synthesis of glutathione. In the second enzymatic reaction, glutathione synthetase
converts glycine to glutathione. What would potentially decrease risks associated
with low levels of glutathione?
Increasing the amount of glycine in the diet
Noncompetitive inhibitor of glutathione synthetase
Uncompetitive inhibitor of glutathione synthetase
Decreasing the amount of glycine in the diet - -answer-Increasing the amount of
glycine in the diet
One way to increase glutathione levels is to increase the activity of glutathione
synthetase. Glutathione synthetase activity can be increased by increasing the
amount of substrate, or glycine available.
