APBIO Cell Respiration

A researcher claims that increased atmospheric carbon dioxide levels cause increased growth rates in plants.

Which of the following statements best supports the researcher’s claim?

(A) Atmospheric carbon dioxide is produced by the burning of fossil fuels, which are formed from the remains of living organisms such as plants.

(B) Atmospheric carbon dioxide is a byproduct of cellular respiration, which is a metabolic process that occurs in plants and other living organisms.

(C) Atmospheric carbon dioxide typically enters plant leaves through stomata, which plants rely on for regulating gas exchange with the atmosphere.

(D) Atmospheric carbon dioxide is the raw material for photosynthesis, which plants rely on for producing sugars and other organic compounds.

(D) Atmospheric carbon dioxide is the raw material for photosynthesis, which plants rely on for producing sugars and other organic compounds.

Which of the following best describes the process by which the bacteria are breaking down the glucose to produce lactic acid?

(A) The bacteria are breaking down sugars in the absence of oxygen.

(B) The bacteria are creating a gradient to synthesize more .

(C) The bacteria are using their mitochondria to break down glucose in the presence of oxygen.

(D) The bacteria are producing in the Krebs cycle that is then converted into lactic acid.

(A) The bacteria are breaking down sugars in the absence of oxygen.

In an experiment, a scientist isolates mitochondria from living cells and suspends them in two different buffered solutions. One solution is maintained at pH 4, while the other solution is maintained at pH 9. The scientist finds that mitochondria in the solution at pH 4 continue to produce ATP but those in the pH 9 solution do not.

The results of the experiment can be used as evidence in support of which of the following scientific claims about mitochondrial activity?

(A) Mitochondria in a cell-free environment are unable to convert thermal energy into ATP.

(B) The electron transport chain pumps electrons from the cytosol to the mitochondrial matrix.

(C) ATP production in mitochondria requires a hydrogen ion gradient that favors movement of protons into the mitochondrial matrix.

(D) ATP synthase molecules change their orientation in relation to the proton gradient across the

(C) ATP production in mitochondria requires a hydrogen ion gradient that favors movement of protons into the mitochondrial matrix.

Which of the following describes a metabolic consequence of a shortage of oxygen in muscle cells?

(A) An increase in blood pH due to the accumulation of lactic acid

(B) No ATP production due to the absence of substrate-level phosphorylation

(C) A buildup of lactic acid in the muscle tissue due to fermentation

(D) A decrease in the oxidation of fatty acids due to a shortage of ATP

(C) A buildup of lactic acid in the muscle tissue due to fermentation

A scientist claims that Elysia chlorotica, a species of sea slug, is capable of photosynthesis.

Which of the following observations provides the best evidence to support the claim?

(A) Elysia chlorotica will die if not exposed to light.

(B) Elysia chlorotica grows when exposed to light in the absence of other food sources.

(C) Elysia chlorotica grows faster when exposed to light than when placed in the dark.

(D) Elysia chlorotica grows in the dark when food sources are available.

(B) Elysia chlorotica grows when exposed to light in the absence of other food sources.

Which of the following best describes the role of and in the process of photosynthesis?

(A) ATP is required for the chemiosmotic production of during photosynthesis.

(B) ATP and NADPH are necessary to initiate the Krebs cycle in photosynthesis.

(C) ATP and NADPH are carriers of chemical energy that is used in the production of carbohydrates.

(D) ATP and NADPH are required to boost electrons to a higher energy state in photosystems and .

(C) ATP and NADPH are carriers of chemical energy that is used in the production of carbohydrates.

A researcher is investigating the effects of a chemical that makes thylakoid membranes permeable to hydrogen ions (H+). Which of the following is the most likely direct effect of adding the chemical to plant cells?

(A) The plant cells will produce less .

(B) The chloroplasts will generate less .

(C) Chlorophyll will require less light energy to excite its electrons.

(D) The plant cells will split fewer water molecules into hydrogen ions and oxygen.

(B) The chloroplasts will generate less .

Which of the following best describes the role of water in photosynthesis?

(A) Water is the only source of protons for the formation of a proton gradient.

(B) Water molecules donate electrons to the electron transport chain.

(C) Water molecules combine with stored carbon molecules to produce glucose.

(D) Water is the terminal electron acceptor for electrons that pass through the electron transport chain.

(B) Water molecules donate electrons to the electron transport chain.

A researcher claims that the synthesis of from and inorganic phosphate is essential to cellular function.

Which of the following statements best helps justify the researcher’s claim?

(A) ATP is a small molecule that some cells release into their environment as a way of communicating with other cells.

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

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

(D) synthase is a mitochondrial enzyme that catalyzes the conversion of and to .

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