Question Video: Explaining How Plants Obtain Oxygen as a Reactant for Cellular Respiration | Nagwa Question Video: Explaining How Plants Obtain Oxygen as a Reactant for Cellular Respiration | Nagwa

Question Video: Explaining How Plants Obtain Oxygen as a Reactant for Cellular Respiration Biology • Second Year of Secondary School

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Plants require oxygen to carry out aerobic respiration. Which of the following is not a method by which plants obtain this oxygen? [A] Oxygen diffuses into the leaf through stomata. [B] Oxygen is breathed in by the plant through open airways in the leaf. [C] Oxygen produced by the plant during photosynthesis is used in respiration. [D] Oxygen is dissolved into water and enters the roots of the plant.

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Video Transcript

Plants require oxygen to carry out aerobic respiration. Which of the following is not a method by which plants obtain this oxygen? (A) Oxygen diffuses into the leaf through stomata. (B) Oxygen is breathed in by the plant through open airways in the leaf. (C) Oxygen produced by the plant during photosynthesis is used in respiration. Or (D) oxygen is dissolved into water and enters the roots of the plant.

Nearly all eukaryotic organisms undergo cellular respiration, a process in which glucose is converted into usable energy. Plants typically undergo a type of respiration called aerobic respiration, in which glucose must be broken down in the presence of oxygen. The result is the production of energy in the form of ATP and the release of carbon dioxide and water.

Plants can obtain oxygen for aerobic respiration through a variety of methods. You likely already know that plants synthesize their own food through photosynthesis, which converts carbon dioxide and water into glucose and oxygen in the presence of sunlight. Photosynthesis and respiration go hand in hand, with the products of both processes providing the reactants of the other. So the oxygen produced during photosynthesis is used as a reactant in aerobic respiration. This is the method described in answer choice (C). And since the question asks us to find the option that is not a method plants use to obtain oxygen, we can go ahead and rule it out.

Plant roots, stems, and leaves all respire and have their own specialized structures for obtaining the needed reactants. The surface of leaves have tiny pores called stomata, or stoma in the singular. Depending on the plant’s need to exchange gases with the atmosphere, stomata can be opened or closed by its guard cells. For example, if a plant requires oxygen beyond what is produced during photosynthesis, oxygen can move through open stomata into the leaves. This is the method given in answer choice (A), so we can eliminate it.

Plant roots have fine, hairlike structures called root hairs. They extend into the air spaces of soil to maximize the surface area through which roots can absorb water. As described in answer (D), this water can contain dissolved minerals and gases, including oxygen. So we can rule out this option as well.

We’ve seen that plants can obtain oxygen through photosynthesis, stomata, and root hairs. But unlike animals, plants do not have a specialized respiratory organ system for gas exchange. This means they do not have open airways, such as trachea and bronchial tubes. Therefore, the correct answer is (B). Plants do not use open airways in the leaf to breathe in oxygen.

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