The proteins necessary for life are assembled by the ribosomes of cells. These proteins include enzymes, which are proteins that can reduce the activation energy needed for certain chemical reactions. One very important role that enzymes play in eukaryotic cells is to allow energy production to occur by catalyzing the chemical reactions involved in cellular respiration.Suppose an enzyme that is involved in cellular respiration is assembled by a ribosome. Where will this enzyme need to be transported in order to perform its function? A. to the nucleus B. to a chloroplast C. to a vacuole D. to a mitochondrion

• BioWizard: The correct answer is D. to a mitochondrion.
  Cellular respiration is a four-stage process where a glucose molecule is gradually broken down into CO2 and H2O and some ATP is produced. The steps are:
  1: Glycolysis- It occurs in the cytosol, glucose is Broken down into two molecules of pyruvate, ATP is made, and NAD+ is converted to NADH.
  2. Transition Reaction-Pyruvate is shuttled into the mitochondria and converted to Acetyl CoA for further break down pyruvate oxidation).
  3. The Krebs Cycle, or Citric Acid Cycle- Occurs at the mitochondrial matrix. The acetyl CoA goes through a cycle of reactions and as a result, ATP, NADH  and FADH2 are produced, CO2 is released.
  4.The Electron Transport Chain-Occursin the inner membrane of mitochondria, The NADH and FADH2 which are made in other steps deposit their electrons in the electron transport chain, (becoming NAD and FAD). As electrons move down the chain, energy is released and used to pump H+ out of the matrix, forming a gradient for further ATP production (oxidative phosphorilation).