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Multiple Choice
Which of the following statements is the best explanation of what happens to the temperature and carbon dioxide concentration during a 1-hour class period in a classroom of 300 students if the heating and air-conditioning is turned off and all doors are kept closed?
A
Temperature goes up but carbon dioxide levels remain constant because heat is a by-product of cellular respiration but carbon dioxide is converted to sugar during cellular respiration.
B
Neither temperature nor carbon dioxide levels change because cellular respiration is 100% efficient and because carbon dioxide produced by cellular respiration is just as rapidly consumed by cellular respiration.
C
Temperature goes down and carbon dioxide levels remain constant. This is because cellular respiration, being an endergonic reaction, requires an input of heat energy from the environment to occur and because carbon dioxide is neither produced nor consumed by cellular respiration.
D
Temperature goes up and the level of carbon dioxide goes down. This is because cellular respiration is an exergonic process that is only about 38% efficient; the remaining energy is lost to the environment as heat. Also, carbon dioxide is being converted to organic molecules such as fats and sugars during cellular respiration.
E
Temperature and the level of carbon dioxide rise as heat and carbon dioxide are by-products of cellular respiration.
Verified step by step guidance
1
Understand the process of cellular respiration: Cellular respiration is a metabolic process that converts glucose and oxygen into energy (ATP), carbon dioxide, and water. It is an exergonic process, meaning it releases energy.
Identify the by-products of cellular respiration: The main by-products are carbon dioxide and heat. This is because the process involves breaking down glucose, which releases energy and carbon dioxide as waste products.
Consider the environment: In a closed classroom with 300 students, each student is continuously performing cellular respiration, contributing to the accumulation of carbon dioxide and heat in the room.
Analyze the effect on temperature: Since cellular respiration releases heat, the temperature in the room is expected to rise as more heat is generated by the students' metabolic activities.
Analyze the effect on carbon dioxide levels: As carbon dioxide is a by-product of cellular respiration, its concentration in the room will also increase over time, given that the room is closed and there is no ventilation to remove the carbon dioxide.