Question

What are the two ways that energy can be passed through the cellular respiration and photosynthesis processes?

Answer 1

Photosynthesis and cellular respiration are the two processes that provide energy to perform different functions for living beings to survive on earth.

Photosynthesis is the process carried out by all autotrophic organisms that capture sunlight and store it in food in the form of glucose molecules. Plants use carbon dioxide, sunlight and water during photosynthesis to produce glucose and oxygen. The energy is stored in the glucose molecules. The anabolic reaction of photosynthesis occurs in chloroplasts of plant cells and is divided into two parts: Light reaction: The light energy of sun is converted to chemical energy in the form of ATP and NADPH both of which are used for next reaction. In the second part known as Calvin cycle, the energy of ATP and NADPH are used for the formation of glucose from carbon dioxide and water molecules.

Energy stored in the glucose molecules of plants is utilized by the process of cellular respiration. Cellular Respiration is a catabolic reaction in which the energy stored in the glucose molecules is utilized for different functions by its breakage in the presence of oxygen into carbon dioxide, water and energy. The cellular respiration occurs in mitochondria of eukaryotic cell of an organism and is divided into three parts: Glycolysis that occurs in cytoplasm of cell divide 6-C glucose into two 3-C Pyruvate molecules. The pyruvate is converted to acetyl coA and is transported into the mitochondria where Krebs cycle and Oxidative phosphorylation occurs.

The Kreb cycle and electron transport chain of mitochondria during respiration generates ATP by breaking of glucose molecules.

Therefore, in the processes of photosynthesis and respiration the energy is passed from plants to animals and vice versa through the anabolic and catabolic pathways of glucose.