Aerobic respiration

Definition

Aerobic respiration is a biological process in which cells convert glucose and oxygen into energy (ATP), carbon dioxide, and water. This process is essential for organisms that require oxygen to efficiently produce energy, and it involves several key stages, including glycolysis, the oxidation of pyruvate, and the citric acid cycle, along with oxidative phosphorylation. The ability to perform aerobic respiration allows organisms to maximize energy yield from nutrients, making it a crucial mechanism for energy metabolism.

5 Must Know Facts For Your Next Test

1. Aerobic respiration produces up to 36-38 ATP molecules per glucose molecule, making it significantly more efficient than anaerobic processes.
2. The oxidation of pyruvate occurs after glycolysis and before entering the citric acid cycle, where each pyruvate is converted into acetyl-CoA while releasing carbon dioxide.
3. The citric acid cycle, also known as the Krebs cycle, further breaks down acetyl-CoA, releasing high-energy electron carriers like NADH and FADH2.
4. In aerobic respiration, oxygen acts as the final electron acceptor in the electron transport chain, enabling the production of water as a byproduct.
5. Prokaryotic organisms can also perform aerobic respiration but do so differently as they lack membrane-bound organelles like mitochondria.

Review Questions

• How do glycolysis and the oxidation of pyruvate contribute to aerobic respiration?
  • Glycolysis initiates aerobic respiration by breaking down glucose into two pyruvate molecules, yielding a small amount of ATP and NADH. Following glycolysis, the oxidation of pyruvate converts each pyruvate into acetyl-CoA while releasing carbon dioxide. This conversion is essential as acetyl-CoA then enters the citric acid cycle to produce more ATP and high-energy electron carriers that are crucial for further energy extraction.
• Discuss the role of oxygen in aerobic respiration and its significance in energy production.
  • Oxygen plays a critical role in aerobic respiration as the final electron acceptor in the electron transport chain. This acceptance allows electrons to flow through the chain, facilitating proton pumping across the mitochondrial membrane. This proton gradient drives ATP synthesis via chemiosmosis. Without oxygen, this process halts, leading to a significant drop in ATP production compared to anaerobic pathways.
• Evaluate how aerobic respiration differs between eukaryotic and prokaryotic organisms, particularly in terms of structure and efficiency.
  • Aerobic respiration differs significantly between eukaryotic and prokaryotic organisms due to structural variations. Eukaryotes perform aerobic respiration within mitochondria where specific reactions like the citric acid cycle and oxidative phosphorylation occur. In contrast, prokaryotes carry out these processes in their cytoplasmic membrane without dedicated organelles. While both types can efficiently produce ATP through aerobic means, eukaryotes can yield slightly more due to compartmentalization that allows for optimized reactions and energy capture.

Related terms

glycolysis:

The first step of cellular respiration where glucose is broken down into pyruvate, yielding a small amount of ATP and NADH.

oxidative phosphorylation:

The final stage of aerobic respiration that occurs in the mitochondria, where ATP is produced through the electron transport chain and chemiosmosis.

mitochondria:

The organelles in eukaryotic cells where aerobic respiration takes place, serving as the site for the citric acid cycle and oxidative phosphorylation.