💍inorganic chemistry ii review

key term - Citric acid cycle

Definition

The citric acid cycle, also known as the Krebs cycle or TCA cycle, is a series of chemical reactions used by all aerobic organisms to generate energy through the oxidation of acetyl-CoA derived from carbohydrates, fats, and proteins. This cycle is crucial for producing ATP and NADH, which are essential for cellular respiration and energy production.

5 Must Know Facts For Your Next Test

  1. The citric acid cycle takes place in the mitochondria of eukaryotic cells and in the cytoplasm of prokaryotic cells.
  2. Each turn of the cycle processes one acetyl-CoA molecule and produces three NADH molecules, one FADH2 molecule, and one ATP (or GTP).
  3. The cycle consists of eight main enzymatic reactions, including condensation, hydration, isomerization, decarboxylation, and substrate-level phosphorylation.
  4. Key intermediates in the citric acid cycle include citrate, isocitrate, alpha-ketoglutarate, succinyl-CoA, succinate, fumarate, and malate.
  5. Regulation of the citric acid cycle occurs at several steps, notably through enzymes such as citrate synthase and isocitrate dehydrogenase, which respond to the energy needs of the cell.

Review Questions

  • How does the citric acid cycle contribute to cellular respiration and energy production?
    • The citric acid cycle plays a vital role in cellular respiration by processing acetyl-CoA to produce energy-rich molecules like NADH and FADH2. These molecules carry high-energy electrons to the electron transport chain where they are used to generate ATP through oxidative phosphorylation. The efficient conversion of substrates into energy through this cycle is essential for sustaining cellular functions.
  • Discuss the importance of regulation in the citric acid cycle and how it affects cellular metabolism.
    • Regulation in the citric acid cycle ensures that the metabolic process adapts to the energy demands of the cell. Key enzymes like citrate synthase and isocitrate dehydrogenase are regulated by energy status indicators such as ATP and NADH levels. This regulation prevents overproduction of intermediates when energy is abundant and ensures efficient use of resources when energy is scarce.
  • Evaluate the impact of disrupted function in the citric acid cycle on overall cellular metabolism and health.
    • Disruption in the function of the citric acid cycle can have severe implications for cellular metabolism and health. If enzymes within the cycle are inhibited or malfunctioning, it can lead to a decrease in ATP production, resulting in insufficient energy for cellular activities. Additionally, accumulation of metabolic intermediates may lead to toxic effects or contribute to diseases like cancer or metabolic disorders due to altered metabolic pathways and cell signaling.