-Cellular respiration is the process that releases energy by breaking down food molecules in the presence of oxygen. Cellular repiration takes place in the mitochodrion. The 3 phases of cellular respiration are Glycolysis (Fermentation), Krebs Cycle, and Electron Transport. Glycolysis takes place in the cytoplasm.
-Glycolysis involves the break down of glucose to form two molecules of pyruvate. These molecules enter the matrix of a mitochondrion, where they start the Krebs cycle.
-Before the Krebs cycle begins, pyruvic acid, which has three carbon atoms, is split apart and combined with an enzyme known as CoA, which stands for coenzyme A. The product of this reaction is a two-carbon molecule called acetyl-CoA.
Rigid skeletons are formed from materials including chitin (in arthropods), calcium compounds such as calcium carbonate (in stony corals and mollusks) and silicate (for diatoms and radiolarians).
