Which two main processes occur during cellular respiration?

• A. Transcription and translation
• B. Glycolysis and the citric acid cycle
• C. Photosynthesis and fermentation
• D. DNA replication and mitosis

Answer: (B)

Verified step by step guidance

1. Understand the concept of cellular respiration: Cellular respiration is the process by which cells convert glucose and oxygen into energy (ATP), carbon dioxide, and water. It is essential for energy production in living organisms.
2. Identify the main stages of cellular respiration: Cellular respiration consists of three main stages: glycolysis, the citric acid cycle (also known as the Krebs cycle), and oxidative phosphorylation. The question specifically asks for the two main processes.
3. Explain glycolysis: Glycolysis is the first stage of cellular respiration, occurring in the cytoplasm. During glycolysis, glucose is broken down into two molecules of pyruvate, producing a small amount of ATP and NADH. This process does not require oxygen.
4. Explain the citric acid cycle: The citric acid cycle occurs in the mitochondria and is the second major stage of cellular respiration. Pyruvate from glycolysis is converted into acetyl-CoA, which enters the cycle. The citric acid cycle generates NADH, FADH2, and ATP while releasing carbon dioxide as a byproduct.
5. Clarify why transcription and translation, photosynthesis and fermentation, and DNA replication and mitosis are incorrect: Transcription and translation are processes related to gene expression, not energy production. Photosynthesis is the process by which plants produce glucose, and fermentation is an anaerobic process. DNA replication and mitosis are involved in cell division, not cellular respiration.