What Is Autotrophs?

Categories of Life

All living things fall into two main categories based on how they obtain chemical energy. There are autotrophs and heterotrophs. Autotrophs are “an organism that uses energy from an external source, such as sunlight, to produce its own food without having to eat other organisms or their remains (page g14).” Within the food web, autotrophs are identified as producers because they convert the energy from sun into the energy they need through photosynthesis and are plants, algae and even some bacteria. In contrast, heterotrophs are “an organism that obtains its energy by eating other organisms or their remains (page g4).” Consumers include herbivores, carnivores, and decomposers. While autotroph are recognized by many in the

Glucose is needed to create the body’s source of energy, ATP, and is found in carbohydrates. Since heterotrophs are unable to produce the food, or glucose, they need for cellular respiration, they obtain this food by consuming autotrophs or other heterotrophs. When a carbohydrate is consumed it begins its journey by traveling through several digestive organs, including the stomach and the small intestine, where it is broken down into the glucose the body needs to create energy. An organ is composed of different tissues that have come together to function in a coordinated manner (textbook page 20, para 7). Therefore digestive organs are organs that work together to breakdown food into the nutrients needed for the organism to function. Once the carbohydrate has been broken down into glucose, through a process of absorption, it enters the blood stream and is transported to cells where it undergoes a chemical process where the glucose is converted to

The two 3-carbon pyruvate molecules that were created from glycolysis are oxidized. One of the carbon bonds on the 3-carbon pyruvate molecule combines with oxygen to become carbon dioxide. The carbon dioxide leaves the 3-carbon pyruvate chain. The remaining 2-carbon molecules that are left over become acetyl coenzyme A. Simultaneously, NAD+ combines with hydrogen to become NADH. With the help of enzymes, phosphate joins with ADP to make and ATP molecule for each pyruvate. Enzymes also combine acetyl coenzyme A with a 4-carbon molecule called oxaloacetic acid to create a 6-carbon molecule called citric acid. The cycle continuously repeats, creating the byproduct of carbon dioxide. This carbon dioxide is exhaled by the organism into the atmosphere and is the necessary component needed to begin photosynthesis in autotrophs. When carbon is chemically removed from the citric acid, some energy is generated in the form of NAD+ and FAD. NAD+ and FAD combine with hydrogen and electrons from each pyruvate transforming them into NADH and FADH2. Each 3-carbon pyruvate molecule yields three NADH and one FADH2 per cycle. Within one cycle each glucose molecule can produce a total of six NADH and two