All living things require carbon in order to function. The process by which carbon travels from our atmosphere into organisms, and then back into the atmosphere, is called the carbon cycle. Recall what you learned in this lesson and then predict how cellular respiration is involved in the carbon cycle. How do you think most animals obtain carbon? How do you think carbon is released back into the atmosphere? Support your ideas by explaining the process of cellular respiration.

Answer 1

Cellular respiration plays a crucial role in the carbon cycle by facilitating the transfer of carbon from living organisms back to the atmosphere. Here’s how the process works and its implications for carbon cycling.

Cellular Respiration and Carbon Cycle

1. Carbon Acquisition by Animals: Most animals obtain carbon primarily through the consumption of organic matter, which includes plants or other animals. Plants absorb carbon dioxide (CO₂) from the atmosphere during photosynthesis, converting it into glucose (C₆H₁₂O₆) and other organic compounds. When animals eat these plants or other animals, they ingest this carbon in the form of organic molecules.

2. Cellular Respiration Process: Cellular respiration is the biochemical process by which cells convert glucose and oxygen into energy, carbon dioxide, and water. The general equation for cellular respiration can be summarized as:

   \[ \text{C₆H₁₂O₆ + 6 O₂} \rightarrow \text{6 CO₂ + 6 H₂O + energy (ATP)} \]

   During this process:

   • Glucose (derived from food) is broken down in the presence of oxygen.
   • This breakdown releases energy (in the form of ATP), which is used by cells to perform various functions.
   • Carbon dioxide (CO₂) is generated as a waste product during this metabolic process.

3. Release of Carbon Back to the Atmosphere: After cellular respiration occurs in animals, the carbon that was originally part of the organic molecules gets transformed into carbon dioxide. This CO₂ is then expelled from the animals’ bodies when they exhale. Therefore, through the respiration of animals, carbon is released back into the atmosphere, where it can re-enter the carbon cycle.

Summary of the Involvement in the Carbon Cycle

• Carbon flow: Carbon moves from the atmosphere to plants through photosynthesis, then to herbivores and carnivores through feeding.
• Respiration: Animals use cellular respiration to derive energy from the carbon in their food, releasing CO₂ back into the atmosphere as a byproduct.
• Continued Cycle: This released CO₂ can be reused by plants, completing the cycle.

In conclusion, cellular respiration is essential for transferring carbon from living organisms back to the atmosphere, thus playing a significant role in maintaining the balance of the carbon cycle. Animals obtain carbon from organic matter in their diet, and through respiration, they contribute to the re-entry of carbon dioxide into the atmosphere, facilitating continuous cycling of carbon in the ecosystem.