Energy, Metabolism and Cells

Unit 2 - IP / Energy, Metabolism and Cells

1. Explain how photosynthesis and respiration are linked in order to provide you with energy from the food you eat.

Photosynthesis is the process by which plants use chlorophyll, which is a pigment, found in the chloroplasts of plants, that absorbs energy from the sun and converts it into glucose (Calvin Cycle). Aerobic Respiration is a process used by animals and plants to break down sugars into usable forms of energy. Aerobic respiration is the opposite reaction of photosynthesis. It uses oxygen to break down the glucose molecules into energy forms that can be readily used by the cells of plants and animals to power necessary functions. Aerobic respiration takes place in the mitochondria, of which each cell has thousands, and converts glucose into adenosine triphosphate (ATP). ATP is the form of energy that all cells require to perform the functions necessary to life. During aerobic respiration, nutrients (sugars) are converted into the form of chemical energy cells can use and store (Krebs Cycle). This process of respiration produces carbon dioxide, water, and ATP as byproducts. These two reactions are involved in how cells make and store energy and in how the gas exchange between oxygen and carbon dioxide occurs.

2. In the absence of oxygen some sells and organisms can use glycolysis coupled to fermentation to produce energy from the sugar created by photosynthesis.

Some microorganisms can trap the energy in sunlight through the process of photosynthesis and store it in the chemical bonds of carbohydrate molecules. The principal carbohydrate formed in photosynthesis is glucose. Other types of microorganisms are unable to perform this process and they must rely upon other carbohydrates in the environment to obtain the energy necessary for their metabolic processes. "Glycolysis is probably the...