Cellular respiration

Definition

Cellular respiration is a metabolic process in which cells convert glucose and oxygen into energy, carbon dioxide, and water. This process is essential for the production of adenosine triphosphate (ATP), which serves as the primary energy currency in cells. Cellular respiration involves several key biochemical pathways, including glycolysis, the Krebs cycle, and the electron transport chain, integrating various aspects of metabolism to maintain cellular function.

5 Must Know Facts For Your Next Test

1. Cellular respiration can occur both aerobically (with oxygen) and anaerobically (without oxygen), affecting the efficiency of ATP production.
2. In aerobic respiration, up to 36-38 molecules of ATP can be generated from one molecule of glucose, while anaerobic processes like fermentation yield only 2 ATP per glucose molecule.
3. The process of cellular respiration is tightly regulated by the availability of substrates and energy demands of the cell, allowing it to adapt to changing conditions.
4. Mitochondria are often referred to as the 'powerhouses' of the cell due to their central role in aerobic respiration and ATP production.
5. Metabolomics studies can reveal changes in metabolite profiles associated with alterations in cellular respiration, linking metabolic pathways to gene expression patterns.

Review Questions

• How do glycolysis and the Krebs cycle contribute to the overall efficiency of cellular respiration?
  • Glycolysis initiates cellular respiration by breaking down glucose into pyruvate, yielding a small amount of ATP and NADH. The Krebs cycle further processes pyruvate in the mitochondria, generating more NADH and FADH2, which are crucial for the electron transport chain. Together, these pathways enhance ATP production by enabling the complete oxidation of glucose while also providing intermediates for other metabolic processes.
• Discuss how oxygen plays a role in cellular respiration and its impact on ATP yield.
  • Oxygen is critical for aerobic cellular respiration as it acts as the final electron acceptor in the electron transport chain. This allows for efficient ATP production through oxidative phosphorylation. When oxygen is present, cellular respiration can yield up to 36-38 ATP molecules per glucose molecule. In contrast, without oxygen, cells rely on anaerobic processes such as fermentation, which only produce 2 ATP per glucose molecule, highlighting oxygen's importance in maximizing energy output.
• Evaluate how disruptions in cellular respiration can affect cellular metabolism and organismal health.
  • Disruptions in cellular respiration can lead to decreased ATP production, impacting all energy-dependent processes within cells. This can result in metabolic disorders where energy metabolism is impaired, leading to conditions like diabetes or mitochondrial diseases. Moreover, altered respiratory efficiency can influence broader physiological functions, contributing to fatigue or organ dysfunction and emphasizing the necessity for proper respiratory function for overall health.

Related terms

Glycolysis:

The first stage of cellular respiration that occurs in the cytoplasm, breaking down glucose into pyruvate while producing a small amount of ATP and NADH.

Krebs Cycle:

A series of enzymatic reactions occurring in the mitochondria that processes pyruvate to produce NADH, FADH2, and ATP, releasing carbon dioxide as a byproduct.

Electron Transport Chain: A series of protein complexes located in the inner mitochondrial membrane that transfer electrons from NADH and FADH2 to oxygen, driving the production of ATP through oxidative phosphorylation.