Exercises: Cellular Respiration and Energy Transfer

Write the balanced chemical equation for aerobic cellular respiration using glucose, and identify the reactants and the products.

Name the organelle where most ATP is produced during aerobic cellular respiration in eukaryotic cells. Then state what ATP is used for in a cell, in one sentence.

Which two substances are reactants in photosynthesis, and which two are products? Say how these relate to the products and reactants of cellular respiration.

In the equation $C_6H_{12}O_6 + 6\,O_2 \rightarrow 6\,CO_2 + 6\,H_2O$ + energy, count the atoms of carbon, hydrogen, and oxygen on each side. Use your counts to explain how this equation shows that matter is conserved.

Sofia exercises hard during soccer practice and her breathing rate increases.

1. a) Explain how a faster breathing rate helps her cells carry out cellular respiration.
2. b) Explain where the carbon atoms in the carbon dioxide she exhales came from.
3. c) Describe the form of energy stored in glucose and the forms it is converted to during respiration.

Compare photosynthesis and cellular respiration by completing these points in a short paragraph or table: the energy source, where each occurs in a plant cell, the direction of energy flow, and how the products of one process become the reactants of the other.

A sealed jar contains a living green plant and a small mouse. The jar sits in bright light for several days, and both organisms survive.

1. a) Explain how the plant and the mouse each affect the concentrations of oxygen and carbon dioxide in the jar.
2. b) Predict what would happen if the jar were placed in complete darkness for several days, and justify your prediction using the equations for both processes.
3. c) Explain how matter is conserved in the jar while energy is not recycled in the same way. Identify where the energy enters the system and where it leaves.

A student measures the carbon dioxide released by germinating pea seeds and by non-germinating (dry) pea seeds at 25 °C using a sensor. After 20 minutes the germinating seeds released 0.80 mg of CO₂ per gram of seeds, and the dry seeds released 0.02 mg per gram.

1. a) Calculate how many times greater the CO₂ release was in the germinating seeds.
2. b) Explain the difference using cellular respiration and the role of enzymes.
3. c) Predict the effect on CO₂ release if the germinating seeds were boiled before the test, and explain why.
4. d) Describe a control for this experiment and identify two variables that should be held constant.