Life Sciences - Term 3 - Week 10

Cellular respiration is a biochemical process through which cells convert glucose and oxygen into energy, carbon dioxide, and water. This process is essential for all living organisms as it provides the energy required for various cellular functions. The overall equation for cellular respiration can be summarized as: C6H12O6 + 6O2 → 6CO2 + 6H2O + energy (ATP).

Cellular respiration consists of three main stages: Glycolysis, the Krebs Cycle, and the Electron Transport Chain. Glycolysis occurs in the cytoplasm and breaks down glucose into pyruvate, producing a small amount of ATP. The Krebs Cycle takes place in the mitochondria, where pyruvate is further broken down, releasing carbon dioxide and transferring energy to electron carriers. Finally, the Electron Transport Chain, also in the mitochondria, uses the electrons from these carriers to produce a large amount of ATP.

In glycolysis, 2 ATP molecules are produced per glucose molecule. In the Krebs Cycle, an additional 2 ATP are generated. The Electron Transport Chain can produce approximately 34 ATP. Therefore, the total ATP yield from one glucose molecule is about 38 ATP. This calculation illustrates the efficiency of cellular respiration in energy production.

Consider the following scenarios: 1) A runner during a marathon relies on aerobic respiration for energy. 2) Yeast in bread-making undergoes anaerobic respiration, producing carbon dioxide and alcohol. Discuss with your partner how the type of respiration affects energy production and by-products in each case.

Choose a specific organism and research how it performs cellular respiration. Focus on whether it uses aerobic or anaerobic respiration, the efficiency of energy production, and any adaptations it has for its environment. Prepare a short report to present to the class.

• ATP
• NADH
• Pyruvate
• Oxygen

Answer: Pyruvate

Glycolysis breaks down glucose into two molecules of pyruvate.

• Cytoplasm
• Nucleus
• Mitochondria
• Cell membrane

Answer: Mitochondria

The Krebs Cycle takes place in the mitochondria of eukaryotic cells.

• Lactic acid
• Ethanol
• Carbon dioxide
• Both Ethanol and Carbon dioxide

Answer: Both Ethanol and Carbon dioxide

Yeast undergoes alcoholic fermentation, producing ethanol and carbon dioxide.

• NADH
• FADH2
• ATP
• Glucose

Answer: ATP

ATP (adenosine triphosphate) is the primary energy carrier in cells.

Answer: Aerobic respiration requires oxygen and produces more ATP, while anaerobic respiration occurs without oxygen and produces less ATP.

Aerobic respiration is more efficient, yielding up to 38 ATP, whereas anaerobic respiration yields only 2 ATP.

Answer: Electron carriers transport electrons to the Electron Transport Chain, facilitating ATP production.

They help transfer energy from glucose breakdown to ATP synthesis.

Answer: C6H12O6 + 6O2 → 6CO2 + 6H2O + energy (ATP)

This equation summarizes the conversion of glucose and oxygen into carbon dioxide, water, and energy.