Video Transcript
Plants require glucose to carry out respiration. By what method do they obtain the majority of this glucose? (A) Glucose is actively transported from the soil and into the roots. (B) Glucose diffuses into the leaf via the open stomata. (C) Glucose is produced during photosynthesis. Or (D) glucose is produced during transpiration.
Cellular respiration is a process that converts sugars to the more useful form of
stored chemical energy called ATP. It occurs in organelles called mitochondria, which are found in nearly all eukaryotic
organisms. Plants use a special type of respiration called aerobic respiration in which oxygen
is required to break down glucose. The result is the production of ATP and the release of carbon dioxide and water.
The question asks us how plants get the glucose needed for respiration. You may remember that plants can make their own food through photosynthesis, in which
energy from sunlight is used to convert carbon dioxide and water to glucose and
oxygen. Since the products of photosynthesis are the reactants of aerobic respiration, the
plant can use the glucose and oxygen produced during photosynthesis to perform
respiration. Any excess oxygen will be released back into the atmosphere, while excess glucose
will be put into storage molecules, such as starch, until it is needed.
Returning to our answer choices, we can see that both (A) and (B) describe methods
that plants use to obtain oxygen. And choice (D) mentions transpiration, which deals with the movement and evaporation
of water from the plant and doesn’t involve glucose. So the correct answer is option (C). Plants obtain the majority of the glucose needed to carry out respiration during
photosynthesis.
