BIOL 215 CWRU: 3 ACTUAL EXAM
PAPER 2026 QUESTIONS WITH
ANSWERS GRADED A+
◍ Aminolevulinate dehydratase (ALAD) is an enzyme that relies on zinc as a
coenzyme. A zinc ion binds to the ALAD active site, where it forms
favorable interactions with the side chains of three amino acids. Researchers
have found that substituting a lead ion for a zinc ion in the ALAD active site
causes inhibition of ALA
D. Which of the following statements best helps explain how the lead ion
causes inhibition of ALAD?.
Answer: It changes the three-dimensional structure of the active site so that
ALAD is no longer compatible with its substrate.
◍ Acetylcholinesterase (AChE) is a protein that catalyzes the conversion of
acetylcholine to acetate and choline. When the concentration of AChE in an
aqueous solution is held constant, the rate of the reaction catalyzed by AChE
increases with increasing concentrations of substrate. At low concentrations
of acetylcholine, a small increase in the substrate concentration results in a
large increase in the reaction rate. At high concentrations of acetylcholine,
however, a large increase in the substrate concentration results in only a
small increase in the reaction rate.Which of the following statements
correctly explains the observed effect of the acetylcholine concentration on
the rate of the enzyme-catalyzed reaction?.
Answer: The active site of AChE is specific for acetylcholine, and only one
substrate molecule can occupy the active site at a time.
◍ law of dominance.
Answer: recessive alleles will always be masked by dominant alleles
◍ locus.
, Answer: Location of a gene on a chromosome
◍ A researcher proposes a model to explain how enzyme-substrate interactions
determine enzyme specificity. The model is based on the idea that substrate
molecules form favorable interactions with the amino acid side chains in an
enzyme's active site.Based on the model, which of the following statements
best explains an enzyme's specificity for a particular substrate molecule?.
Answer: A molecule with negative charges interacts with positively charged
side chains in the enzyme's active site.
◍ allele.
Answer: Different forms of a gene
◍ Catalase is an enzyme found in yeast cells that facilitates the chemical
breakdown of hydrogen peroxide to water and oxygen gas. An experiment
was conducted to determine the effect of pH on catalase function. Five
buffer solutions of varying pH (2, 4, 6, 8, and 10) were prepared and added
to separate test tubes. Hydrogen peroxide (H2O2) was added to each test
tube. Yeast was added, and the reactions were timed. After 1 minute the
amount of oxygen gas released was determined by measuring the foam layer
produced in each test tube. Figure 1 illustrates the experimental setup.Figure
1. Illustration of experimental procedureA set of five additional test tubes
were prepared and used as controls. Which of the following best describes
the contents expected to be contained in one of the five control test tubes?.
Answer: pH 4 buffer solution and hydrogen peroxide only
◍ dominant.
Answer: An allele that is always expressed
◍ recessive.
Answer: An allele that is masked when a dominant allele is present
◍ homozygote.
Answer: organism that inherits two alleles of the same type for a given gene
◍ A student designs an experiment to investigate the influence of temperature
on enzyme function. The student's plan is presented in Table 1.Which test
, tubes are controls in the experiment?.
Answer: Test tubes 1, 3, 5, and 7
◍ A researcher designs an experiment to investigate whether soil bacteria
trigger the synthesis of defense enzymes in plant roots. The design of the
experiment is presented in Table 1. For each group in the experiment, the
researcher will determine the average rate of change in the amount of
defense enzymes in the roots of the seedlings.Which of the following
statements best helps justify the inclusion of group 2 as one of the controls
in the experiment?.
Answer: It will show whether the changes observed in group 1 depend on
the metabolic activity of soil bacteria.
◍ heterozygote.
Answer: organism that inherits two different alleles for a given gene
◍ Pectinase is a protein that catalyzes the breakdown of pectic polysaccharides
in plant cell walls. A researcher designs an experiment to investigate the
effect of salinity on the ability of pectinase to lower the activation energy of
the reaction involved. The design of the experiment is presented in Table 1.
For each test tube, the researcher will measure the amount of product
formed over 20 minutes.Which of the following statements best helps justify
the inclusion of test tube 5 in the experiment?.
Answer: It will act as a control for test tube 6 by showing the effect of the
presence or absence of the enzyme.
◍ Researchers investigated the effect of urea on the three-dimensional
structure of a certain enzyme. The researchers dissolved the enzyme in an
aqueous buffer solution and added urea to the solution. The enzyme did not
appear to have a secondary or tertiary structure. The researchers carefully
removed the urea from the solution and determined that the enzyme had the
original secondary and tertiary structure again.Based on the results of the
experiment, which of the following statements best predicts the effect of
urea on the enzyme's function?.
Answer: AFunction will be disrupted by adding the urea and regained by
PAPER 2026 QUESTIONS WITH
ANSWERS GRADED A+
◍ Aminolevulinate dehydratase (ALAD) is an enzyme that relies on zinc as a
coenzyme. A zinc ion binds to the ALAD active site, where it forms
favorable interactions with the side chains of three amino acids. Researchers
have found that substituting a lead ion for a zinc ion in the ALAD active site
causes inhibition of ALA
D. Which of the following statements best helps explain how the lead ion
causes inhibition of ALAD?.
Answer: It changes the three-dimensional structure of the active site so that
ALAD is no longer compatible with its substrate.
◍ Acetylcholinesterase (AChE) is a protein that catalyzes the conversion of
acetylcholine to acetate and choline. When the concentration of AChE in an
aqueous solution is held constant, the rate of the reaction catalyzed by AChE
increases with increasing concentrations of substrate. At low concentrations
of acetylcholine, a small increase in the substrate concentration results in a
large increase in the reaction rate. At high concentrations of acetylcholine,
however, a large increase in the substrate concentration results in only a
small increase in the reaction rate.Which of the following statements
correctly explains the observed effect of the acetylcholine concentration on
the rate of the enzyme-catalyzed reaction?.
Answer: The active site of AChE is specific for acetylcholine, and only one
substrate molecule can occupy the active site at a time.
◍ law of dominance.
Answer: recessive alleles will always be masked by dominant alleles
◍ locus.
, Answer: Location of a gene on a chromosome
◍ A researcher proposes a model to explain how enzyme-substrate interactions
determine enzyme specificity. The model is based on the idea that substrate
molecules form favorable interactions with the amino acid side chains in an
enzyme's active site.Based on the model, which of the following statements
best explains an enzyme's specificity for a particular substrate molecule?.
Answer: A molecule with negative charges interacts with positively charged
side chains in the enzyme's active site.
◍ allele.
Answer: Different forms of a gene
◍ Catalase is an enzyme found in yeast cells that facilitates the chemical
breakdown of hydrogen peroxide to water and oxygen gas. An experiment
was conducted to determine the effect of pH on catalase function. Five
buffer solutions of varying pH (2, 4, 6, 8, and 10) were prepared and added
to separate test tubes. Hydrogen peroxide (H2O2) was added to each test
tube. Yeast was added, and the reactions were timed. After 1 minute the
amount of oxygen gas released was determined by measuring the foam layer
produced in each test tube. Figure 1 illustrates the experimental setup.Figure
1. Illustration of experimental procedureA set of five additional test tubes
were prepared and used as controls. Which of the following best describes
the contents expected to be contained in one of the five control test tubes?.
Answer: pH 4 buffer solution and hydrogen peroxide only
◍ dominant.
Answer: An allele that is always expressed
◍ recessive.
Answer: An allele that is masked when a dominant allele is present
◍ homozygote.
Answer: organism that inherits two alleles of the same type for a given gene
◍ A student designs an experiment to investigate the influence of temperature
on enzyme function. The student's plan is presented in Table 1.Which test
, tubes are controls in the experiment?.
Answer: Test tubes 1, 3, 5, and 7
◍ A researcher designs an experiment to investigate whether soil bacteria
trigger the synthesis of defense enzymes in plant roots. The design of the
experiment is presented in Table 1. For each group in the experiment, the
researcher will determine the average rate of change in the amount of
defense enzymes in the roots of the seedlings.Which of the following
statements best helps justify the inclusion of group 2 as one of the controls
in the experiment?.
Answer: It will show whether the changes observed in group 1 depend on
the metabolic activity of soil bacteria.
◍ heterozygote.
Answer: organism that inherits two different alleles for a given gene
◍ Pectinase is a protein that catalyzes the breakdown of pectic polysaccharides
in plant cell walls. A researcher designs an experiment to investigate the
effect of salinity on the ability of pectinase to lower the activation energy of
the reaction involved. The design of the experiment is presented in Table 1.
For each test tube, the researcher will measure the amount of product
formed over 20 minutes.Which of the following statements best helps justify
the inclusion of test tube 5 in the experiment?.
Answer: It will act as a control for test tube 6 by showing the effect of the
presence or absence of the enzyme.
◍ Researchers investigated the effect of urea on the three-dimensional
structure of a certain enzyme. The researchers dissolved the enzyme in an
aqueous buffer solution and added urea to the solution. The enzyme did not
appear to have a secondary or tertiary structure. The researchers carefully
removed the urea from the solution and determined that the enzyme had the
original secondary and tertiary structure again.Based on the results of the
experiment, which of the following statements best predicts the effect of
urea on the enzyme's function?.
Answer: AFunction will be disrupted by adding the urea and regained by
