The correct option is (c) 1 and 3 only.
Explanation
Cellular respiration is the biochemical process occurring within cells where food molecules (primarily glucose) are broken down to release energy. This energy is trapped in the form of Adenosine Triphosphate (ATP), which fuels various cellular activities.
Statement-wise Analysis
- Statement 1 is Correct: The fundamental purpose of cellular respiration is the breakdown of food (glucose) to release energy. This energy is essential for the cell to perform its metabolic functions.
- Statement 2 is Incorrect: The breakdown of food does not always require oxygen. While aerobic respiration uses oxygen to completely oxidize glucose, anaerobic respiration (fermentation) occurs in the absence of oxygen (e.g., in yeast or muscle cells during heavy exercise), producing less energy.
- Statement 3 is Correct: As the name suggests, cellular respiration takes place inside the cell. The process begins in the cytoplasm (glycolysis) and, in aerobic organisms, continues and completes within the mitochondria.
Key Takeaway: Cellular respiration is an intracellular energy-releasing process that can occur either in the presence of oxygen (aerobic) or in its absence (anaerobic).