Final answer:
Cellular respiration is the process by which cells convert glucose into ATP, the usable form of energy for the body's cells. It involves several stages, including glycolysis, the Krebs Cycle, and Oxidative phosphorylation. The systems involved in providing the necessary components for cellular respiration are the digestive, respiratory, and cardiovascular systems.
Step-by-step explanation:
What is Cellular Respiration?
At the level of the cells, food is broken down through a process called cellular respiration. This biological process is how cells convert nutrients from the food we eat into usable energy, specifically adenosine triphosphate (ATP). When we consume foods such as an apple or a candy bar, they contain complex molecules that cells cannot use directly for energy. These complex food items are broken down into simpler forms like glucose, which is the primary molecule that cells use to generate energy through cellular respiration.
Glycolysis and Metabolic Pathways
The initial stage of cellular respiration is glycolysis, where a 6-carbon glucose molecule is broken down into two 3-carbon pyruvate molecules, in the process producing ATP. The reactions that break down glucose and release energy in cellular respiration are part of the cell's metabolism, including other metabolic processes that build complex molecules (anabolism) and those that break them down (catabolism).
Post glycolysis, the cellular respiration process includes the Transformation of Pyruvate, the Krebs Cycle (or citric acid cycle), and Oxidative phosphorylation. Through these stages, glucose reacts with oxygen to produce carbon dioxide, water, and ATP—the energy currency of the cell.
Cellular respiration not only involves the muscular and digestive systems for procuring glucose but also the respiratory system for acquiring oxygen and the cardiovascular system for transporting these substances.
In conclusion, the correct option that describes the process by which food is broken down at the cell level is cellular respiration.