Which statement describes the major role of lipids within a cell?

What molecules control the reaction rate of photosynthesis?

Which of these supply the main energy source used in cellular respiration?

When the cells of most organisms freeze, they burst. Which property of water causes this to occur?

Amylase is an enzyme that allows the human body to digest starch. Which of these diagrams best represents part of the structure of amylase?

A dog gets many nutrients from its food including amino acids. Which of these can be built directly using the amino acids?

The cell wall of a plant helps the plant cell maintain its shape. What is the main structural component of the cell wall of a plant?

Which of these are the repeating units that form a DNA molecule?

Most carbohydrates in the human body are

Which of these represents the structure of messenger RNA?

A scientist removed the cell membranes from bacteria cells in a culture. She analyzed the cell membranes for specific molecules. Which of these was probably the most common type of molecule present in the bacteria cell membranes?

Glucose is a building block of carbohydrates. Which of these best describes glucose?

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.

What type of molecule is catalase?

Which of these correctly matches the molecule with its function?

Fluoride is added to drinking water supplies in many states. People cannot see fluoride in the water because it

Use the diagram below to answer Numbers 5 and 6.

Use the diagram below to answer the following item.

Which of these is a nucleotide?

Use the diagram below to answer the following item.

Which of these is a sugar?

Before the three-dimensional structure of DNA was discovered, scientists knew that DNA contained nitrogen bases. The chart below shows the percentages of nitrogen bases in a DNA sample.

Explain how the relative amounts of nitrogen bases in a DNA molecule is closely linked to DNA replication. In your response, be sure to

• describe the composition of a DNA molecule
• describe the structure of a DNA molecule
• describe the process by which DNA replicates
• explain how the arrangement of nitrogen bases ensures the relatively error-free replication of DNA molecules

Write your answer in your Answer Book.

Some adult insects are unable to swim but are able to walk on top of water. What characteristic of water enables these insects to walk on top of water?

In the early 1900s, many children had a disease called rickets. Research showed that the children had a deficiency of a vitamin that is necessary for the proper formation of bones.

Which of these vitamins was lacking in the diets of these children?

Use the information and the diagram below to answer the following item.

Catalase is an enzyme found in the tissues of plants and animals, including humans. Catalase helps prevent a toxic buildup of hydrogen peroxide in cells by breaking it down into water and oxygen gas. Several students conduct an experiment to test the effects of pH on the activity of catalase. Each test tube contains a solution of hydrogen peroxide and water at various pH levels. The liver tissue is a source of catalase. The diagram below represents the results of their experiment.

Which of the following are the building blocks of catalase?

Both DNA and RNA

Water dissolves many substances. This occurs because water has

The characteristics listed below can be used to describe some molecules.

1. inorganic
2. supplies energy and fiber
3. component of plant cell walls
4. part of DNA
5. made of nucleotides

Which of these sets of characteristics describes a carbohydrate?