Energy Case

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 from energy from the sun and converts it into glucose (Calvin Cycle). Aerobic respiration has the opposite reaction of photosynthesis this process is used by animals and plants that break down sugars into usable forms of energy. Aerobic respiration uses oxygen to break down the glucose molecules to form energy that can be used by cells of plants and animals to power necessary functions. In the mitochondria the aerobic respiration takes place and in each cell there are thousands and it converts glucose into adenosine triphosphate (ATP) and this is a form of energy that requires all cells to perform necessary functions to life and during the aerobic respiration nutrients are converted to forms of chemical energy cells (Krebs Cycle). This is a process of respiration that produces carbon dioxide, water, and ATP as byproducts and 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 cells and organisms can use glycolysis coupled to formation to produce energy from the sugar created by photosynthesis.

Some microorganisms can trap energy into sunlight through the process of photosynthesis and store it in the chemical bonds of carbohydrate molecules. "Glycolysis is probably the oldest known way of producing ATP. There is evidence that the process of glycolysis predates both the existence of oxygen (O2) in the Earth's atmosphere and organelles in cells" Carter, 2011). In environments where is there is no oxygen available, organisms can still use glucose that is metabolized to produce ATP using fermentation process. This is an anaerobic process which energy can be released from glucose without oxygen being available.

3. Cells use enzymes as biological catalysts to increase or accelerate the rate of reactions, such as those in photosynthesis or glycolysis. This allows reactions to occur under conditions that sustain life.

There are chemical reactions in cells of all living things that operate in the presence of biological catalysts call enzymes. The enzymes are composed of proteins and there are three main steps of the cycle of enzyme-substrate interactions:

* Enzyme + substrate: This is the binding of the substrate by the enzyme. The enzyme includes an active site that can accommodate the size, shape, and electron configuration of its substrate or substrates.

* Enzyme-substrate complex: This is the time the active site is associated with the substrate.

* Enzyme + product: After interaction has taken place, a change in shape