BIOL 1011 Midterm Exam with Complete
Solutions| 100% Solved
A student performs the experiment examining catalase activity, but increases the concentration of
H2O2 from 3% to 6% while keeping the concentration of catalase the same.
How would using a higher concentration of H2O2 affect the amount of O2 gas produced in the
first 15 seconds? Why? The amount of O2 gas produced would not change significantly
because all of the catalase active sites would already be occupied by the substrate, H2O2.
In setting up Experiment 2, a student inadvertently adds 10 mL10 mL of 3% H2O23% H2O2
instead of 5 mL5 mL to the test tube that already contains 5 mL5 mL of water. This gives the
student a total volume of 15 mL15 mL of diluted H2O2H2O2 solution in the test tube.
Calculate the final concentration of H2O2H2O2 in the test tube. H2O2H2O2
concentration = 2
Match each description to the appropriate buffer based on the buffer's pH value.Each buffer may
have more than one applicable description. pH = 1
- most acidic
- highest H ion concentration
pH = 5.5
- moderately acidic
pH = 7
,- neutral
pH = 7.4
- slightly alkaline
pH = 13
- most alkaline
- highest OH ion concentration
What conclusions about the catalase enzyme can be drawn from this experiment? 1. the
catalase enzyme is inactive at pH 2
2. catalase functions over a broad pH range
Like many enzymes, catalase functions across a range of pH values. A student performs an
experiment to determine the pH at which catalase functions the most quickly and efficiently. The
target pH value is the pH optimum.
What additional pH buffers should the student test to determine the pH optimum for catalase?
buffers with pH 7, 8, 9, and 11
Identify the procedure that would determine the precise optimal temperature for catalase
function. Test O2 production using narrower temperature intervals between 21.5 °C and
60 °C.
, In this lab (Photosynthesis), you measure the net rate of gas exchange for the combined
processes of photosynthesis and cellular respiration by measuring oxygen volume using a gas
syringe.
Why are you able to specifically measure the volume of oxygen in these experiments?
Carbon dioxide is highly soluble in water, whereas oxygen is relatively insoluble in water.
In Experiment 1, a student measures 7.46 mL7.46 mL of oxygen (O2)(O2) produced at 20 °C20
°C and a light intensity of 5.
In Experiment 2, the student measures 1.38 mL1.38 mL of oxygen (O2)(O2) consumed at 20
°C20 °C and a light intensity of 0.
What was the total volume of O2O2 produced by the process of photosynthesis in the Elodea
branch? 8.84 mL
According to your data from Experiment 3 (photosynthesis lab), how did varying light intensity
affect the rate of photosynthesis? The rate of photosynthesis increased as the light
intensity increased, approaching a maximum rate at light intensity 4.
Using the data from Experiments 1 and 4 (photosynthesis lab), which temperature resulted in the
greatest production of oxygen gas? 30 C
A student adds another temperature, 50 °C,50 °C, to the experiment that examines the effect of
temperature on the rate of photosynthesis. At this temperature, there is no change in gas volume
in the syringe during the 60 minutes.
Why was no O2O2 gas produced at 50 °C? The enzymes needed for photosynthesis
become denatured at high temperatures.
Solutions| 100% Solved
A student performs the experiment examining catalase activity, but increases the concentration of
H2O2 from 3% to 6% while keeping the concentration of catalase the same.
How would using a higher concentration of H2O2 affect the amount of O2 gas produced in the
first 15 seconds? Why? The amount of O2 gas produced would not change significantly
because all of the catalase active sites would already be occupied by the substrate, H2O2.
In setting up Experiment 2, a student inadvertently adds 10 mL10 mL of 3% H2O23% H2O2
instead of 5 mL5 mL to the test tube that already contains 5 mL5 mL of water. This gives the
student a total volume of 15 mL15 mL of diluted H2O2H2O2 solution in the test tube.
Calculate the final concentration of H2O2H2O2 in the test tube. H2O2H2O2
concentration = 2
Match each description to the appropriate buffer based on the buffer's pH value.Each buffer may
have more than one applicable description. pH = 1
- most acidic
- highest H ion concentration
pH = 5.5
- moderately acidic
pH = 7
,- neutral
pH = 7.4
- slightly alkaline
pH = 13
- most alkaline
- highest OH ion concentration
What conclusions about the catalase enzyme can be drawn from this experiment? 1. the
catalase enzyme is inactive at pH 2
2. catalase functions over a broad pH range
Like many enzymes, catalase functions across a range of pH values. A student performs an
experiment to determine the pH at which catalase functions the most quickly and efficiently. The
target pH value is the pH optimum.
What additional pH buffers should the student test to determine the pH optimum for catalase?
buffers with pH 7, 8, 9, and 11
Identify the procedure that would determine the precise optimal temperature for catalase
function. Test O2 production using narrower temperature intervals between 21.5 °C and
60 °C.
, In this lab (Photosynthesis), you measure the net rate of gas exchange for the combined
processes of photosynthesis and cellular respiration by measuring oxygen volume using a gas
syringe.
Why are you able to specifically measure the volume of oxygen in these experiments?
Carbon dioxide is highly soluble in water, whereas oxygen is relatively insoluble in water.
In Experiment 1, a student measures 7.46 mL7.46 mL of oxygen (O2)(O2) produced at 20 °C20
°C and a light intensity of 5.
In Experiment 2, the student measures 1.38 mL1.38 mL of oxygen (O2)(O2) consumed at 20
°C20 °C and a light intensity of 0.
What was the total volume of O2O2 produced by the process of photosynthesis in the Elodea
branch? 8.84 mL
According to your data from Experiment 3 (photosynthesis lab), how did varying light intensity
affect the rate of photosynthesis? The rate of photosynthesis increased as the light
intensity increased, approaching a maximum rate at light intensity 4.
Using the data from Experiments 1 and 4 (photosynthesis lab), which temperature resulted in the
greatest production of oxygen gas? 30 C
A student adds another temperature, 50 °C,50 °C, to the experiment that examines the effect of
temperature on the rate of photosynthesis. At this temperature, there is no change in gas volume
in the syringe during the 60 minutes.
Why was no O2O2 gas produced at 50 °C? The enzymes needed for photosynthesis
become denatured at high temperatures.
