Think about what you know about biomolecules. In your notebook, draw a diagram of photosynthesis and cellular respiration. Use your diagram to answer the following questions.

Question

How is matter conserved during the processes of photosynthesis and cellular respiration?
Why is the oxygen production of the plants different at different times of the day?
What would likely happen to a plant if it was placed in a completely dark environment? Explain your answer in terms of the plant’s ability to create the four main types of biomolecules.
Review your diagrams to ensure that you have thoroughly answered the questions. If desired, you can find additional evidence from the lessons to support your answers. When you are ready, continue on to the Try This activity on the next page.

Answer 1

Diagram of Photosynthesis and Cellular Respiration

While I can't draw a diagram directly, I can describe what your diagram should include:

1. Photosynthesis (occurs in chloroplasts):

   • Inputs: Carbon dioxide (CO2) + Water (H2O) + Light energy (from the sun).
   • Outputs: Glucose (C6H12O6) + Oxygen (O2).
   • Key Reaction:
     • 6CO2 + 6H2O + light energy → C6H12O6 + 6O2.

2. Cellular Respiration (occurs in mitochondria):

   • Inputs: Glucose (C6H12O6) + Oxygen (O2).
   • Outputs: Carbon dioxide (CO2) + Water (H2O) + Energy (ATP).
   • Key Reaction:
     • C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP.

Questions and Answers

1. How is matter conserved during the processes of photosynthesis and cellular respiration?

Matter is conserved during these processes through a cyclical relationship. In photosynthesis, plants convert carbon dioxide and water into glucose and oxygen using light energy. The glucose produced serves as energy storage, and the oxygen is released as a byproduct. During cellular respiration, organisms (including plants) use oxygen to break down glucose to release energy, producing carbon dioxide and water as byproducts. Therefore, the carbon dioxide and water produced by cellular respiration are used again in photosynthesis, illustrating the conservation of matter as both processes rely on the same molecules cycling through.

2. Why is the oxygen production of the plants different at different times of the day?

Oxygen production in plants varies throughout the day due to changes in the availability of sunlight. Photosynthesis occurs primarily during the daytime when sunlight is available, resulting in high oxygen production. At night, there is no light for photosynthesis, so plants primarily rely on cellular respiration, which consumes oxygen instead of producing it. Thus, oxygen production peaks during daylight hours and drops to zero at night.

3. What would likely happen to a plant if it was placed in a completely dark environment? Explain your answer in terms of the plant’s ability to create the four main types of biomolecules.

If a plant were placed in a completely dark environment, it would be unable to conduct photosynthesis. Without sunlight, the plant cannot produce glucose or oxygen, which are critical for its energy needs and metabolic processes. Over time, the plant would deplete its stored glucose reserves, leading to a lack of energy for respiration. Since glucose serves as a precursor for producing other biomolecules (like carbohydrates, lipids, proteins, and nucleic acids), the plant would struggle to synthesize these macromolecules. Eventually, this could lead to the plant's death due to starvation, as it would not be able to produce or acquire the necessary materials to sustain growth, repair, and reproduction.

Use this information to ensure your diagram and notes are complete and ready for your further activities!