Biology 101: Metabolism - Common Metabolism Concepts

Metabolism occurs in all living things, it is a set of chemical reactions that allow living things to adapt to their environments, grow, and function on a typical basis. Metabolism has two different categories catabolic reactions and anabolic reactions.

Catabolic reactions are the breaking down of molecules to release energy. This sort of reaction is commonly seen in the breaking down of foods.

Anabolic reactions are reactions that use energy to create cell necessities such as proteins. Anabolic creates while catabolic breaks down.

"Virtually all living things are dependent on solar energy." This is because all things need light from the sun to survive in one way or another. First and foremost, the process of photosynthesis takes in the CO2 that our bodies can't really use and after a series of processes, releases oxygen, a substance we need to survive. Photosynthesis is comprised of two parts, one being a light dependant part. As such, without solar energy, plants aren't able to survive, aren't able to undergo photosynthesis, and thus aren't able to support other life forms.

Besides the lack of oxygen and the excess of CO2 in the environment due to this fact, without plant life the large cycle that is life collapses (animals have no plants to eat and die, humans have neither plants nor animals to eat and thus die out).

Additionally, solar energy is used within the body as energy for cells and as a means for processing some important vitamins.

Photosynthesis in plants is one metabolic process, what is it?

Photosynthesis is the process in which CO2 is taken in and oxygen is produced and emitted into the environment.

How does the body get energy from food?

After consuming the food it is digested. The digestion processes breaks the food down into nutrient molecules. The waste is discarded, and the nutrient molecules are then taken in by the cells of the body. The cells use these nutrient to produce energy when you need it, and store it if you don't.

ATP changes with oxygen concentration. Why? How do our bodies naturally increase the oxygen supply to our muscles?
Oxygen is required to produce ATP, so naturally ATP changes with the concentration of oxygen present. Muscles metabolize glucose into ATP, so if oxygen levels are low the muscles aren't able to make this conversion. As such, oxygen supplies can be delivered to the muscles through breathing harder or faster than usual. In essence you must take in more oxygen in order for your muscles to receive the necessary oxygen to convert glucose to ATP.

One popular biology experiment involves putting a plant in darkness for several days, cutting off a leaf, and then measuring to see if starch is present. The answer is no, but why is starch not present in these leaves when it is present in leaves that are left in sunlight?

This lack of starch is due to the fact that the plant uses it for energy when lack of sunlight is available. Plants convert the sugar they produce to starch as a method of storage, thus if you test for starch in a plant leaf the result will be positive. However, if the plant is left in darkness it will need to dip into its stores in order to survive. So, when you pull the plant from the darkness and test for starch the result will be negative because they plant has used that starch.