. Guillermo was finding it difficult to walk up the steps to his family’s apartment. His doctor thinks that his cells might not be getting enough oxygen or glucose. Which body systems should the doctor test in order to find out whether Guillermo’s cells are getting enough oxygen and glucose and why? (Sentence starter: The body systems Guillermo should have tested are .

Because oxygen is the combustion  fuel and glucose  is the substrate needed for synthesis of energy as ATPs during cellular respiration.Therefore Guillermo lacks enough energy as ATPs in her  body cells, especially skeletal muscles cells to complete the task of ascending the s steps.

For all the mitochondrial in cells(sites of energy production)   to receive needed glucose,and other metabolites needed for  energy synthesis; an efficient transport system is needed, so that  these materials   are available  immediately, in required amount. This system is called circulatory system.

And for the the supply of combustion fuel (oxygen) needed for the completion of the ATP synthesis mechanisms;  respiratory systems which  convey oxygen from the external environments to the circulatory system through breathing mechanisms, for distribution is needed.

Thus the  doctor needs to test both the circulatory and respiratory systems.

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