AP Biology Unit 3

A researcher claims that the synthesis of ATP from ADP and inorganic phosphate (Pi) is essential to cellular function. Which of the following statements best helps justify the researcher’s claim?

• ADP is a small molecule that some cells release into their environment as a way of communicating with other cells.

• ATP hydrolysis is an energy-releasing reaction that is often coupled with reactions that require an input of energy.

• Inorganic phosphate (Pi) is a substance that cells typically acquire from their environment.

• ATP synthase is a mitochondrial enzyme that catalyzes the conversion of ADP and Pi to ATP.

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Pyruvate dehydrogenase is an enzyme that converts pyruvate to acetyl-CoA. Acetyl-CoA is further metabolized in the Krebs cycle. A researcher measured the accumulation of acetyl-CoA in a reaction containing pyruvate and pyruvate dehydrogenase under several different conditions. Which of the following best describes the cellular location where pyruvate dehydrogenase is most likely active?

• The cytosol

• The lysosomes

• The nucleus

• The mitochondrial matrix

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The figures illustrate the similarities between ATP synthesis in mitochondria and chloroplasts.  The figures can best assist in answering which of the following questions?

• Do electron transport chains create a gradient so that ATP synthase can generate ATP molecules?

• What are the sources of energy that drive mitochondrial and chloroplast electron transport systems?

• What is the optimal temperature at which ATP synthase chemically converts ADP and a phosphate group into one molecule of ATP?

• What is the evolutionary relationship between the ATP synthase in mitochondria and the ATP synthase in chloroplasts?

Scientists were interested in testing the effects of rotenone, a broad-spectrum pesticide, on a cell culture. Cell culture AA was used as a control, while culture BB was treated with rotenone. After a period of time, the scientists measured the concentration of several metabolites in the mitochondria of cells in both cultures. Their results are shown in the table. Based on the data in the table, which of the following best explains the effects of rotenone on cellular respiration?

• Rotenone acts as an inhibitor of the enzymes in the Krebs cycle.

• NADH, produced during glycolysis, is not able to enter the mitochondria because transport proteins are blocked from entering.

• Treated cells are not able to break down NADH because certain enzymes of the electron transport chain are inhibited.

• Rotenone acts as an allosteric inhibitor of glycolytic enzymes, thus inhibiting cellular respiration.

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Label the cellular respiration equation:

a

b

c

glucose

CO2

oxygen

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Compare and contrast the functions of the smooth and rough endoplasmic reticulum.

• Both synthesize proteins; the rough ER also detoxifies chemicals.

• The smooth ER synthesizes lipids; the rough ER synthesizes proteins.

• Both store calcium ions; the smooth ER also synthesizes proteins.

• The rough ER detoxifies chemicals; the smooth ER stores genetic material.

Which of the following best describes the function of the nucleolus within the nucleus?

• It stores DNA.

• It synthesizes ribosomal RNA.

• It regulates cell division.

• It modifies proteins.

What is the primary function of the mitochondria in eukaryotic cells?

• Photosynthesis

• Protein synthesis

• Energy production

• Lipid storage

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Explain how the structure of the cell membrane contributes to its function.

• The rigid structure provides support and protection.

• The fluid mosaic model allows selective permeability.

• The thick layer prevents all substances from entering.

• The solid structure allows for easy transport of materials.

Which organelle is responsible for modifying, sorting, and packaging proteins for secretion?

• Ribosome

• Golgi apparatus

• Endoplasmic reticulum

• Lysosome