The table below lists enzymes that function in different locations in the human body, and the normal pH and temperature ranges of these locations.

Use your understanding of the structure and function of enzymes to

• predict how the activity of pepsin will change after it moves from the stomach to the small intestine
• explain your prediction using data from the table
• describe how changes in pH and temperature affect enzyme activity
• predict how a fever of 40°C would affect enzyme activity

Write your answer in your Answer Book.

Which of these substances moves across cell membranes by osmosis?

A scientist believes that a factory has been dumping acid into a local river. To test this hypothesis, which property of water should the scientist monitor?

In an experiment, a group of students placed ten raisins in a container with 100 milliliters of water. They covered the container and let the raisins sit overnight. The students removed the raisins from the container and observed that they were larger. They also observed that the volume of water in the container had decreased.

What happened to the raisins to cause them to become larger? In your response, be sure to

• name the process that caused the raisins to become larger
• describe how this process caused the raisins to become larger
• explain the role of this process in living systems

Write your answer in your Answer Book.

Use the information and the graph below to answer the following question.

Catalase is an enzyme found in plant and animal cells. Hydrogen peroxide is a harmful substance found in cells. Catalase causes hydrogen peroxide to break down into water and oxygen.

A student conducted an experiment to determine whether plant and animal cells have the same amount of catalase. She used liver and potato tissues in the experiment. The student followed the procedures below.

1. Label two identical test tubes, 1 and 2.
2. Pour 10 milliliters of hydrogen peroxide solution (1% concentration) into each test tube.
3. Add a small piece of liver tissue to Test Tube 1.
4. Add a small piece of potato tissue to Test Tube 2.
5. Collect the oxygen released from each test tube for 25 seconds.
6. Measure and record the volume of oxygen for each test tube.

The graph below shows the results from the experiment.

The student conducted a second experiment. She boiled the liver tissue completely and added it to the hydrogen peroxide solution. She observed that little to no oxygen was released in the second experiment.

Which of these statements best supports the student’s observations?

Read the decription of the experiment and use the table of results below to answer the following question.

A student designed an experiment to see if plants grow better when watered with a sugar solution. He divided the plants into six groups, measured the initial height of each plant, and calculated the average height for each group. Once a week for two months, he watered the plants in each group using a different sugar solution for each plant group. At the end of two months, he measured the final height of each plant and calculated the average height for each group. The student’s data are shown in the table below.

Which of these statements explains why the plants in Groups E and F died?

A researcher is testing the effect of acid rain on living organisms. She takes a tissue sample and places it in acid rainwater, which decreases its pH. As the pH decreases, what will most likely happen to the enzyme reaction rates in the cells of this tissue?

Many bacteria live in fresh water. Which of these statements best describes what will happen when freshwater bacterial cells are placed in salt water?