16. The Krebs cycle occurs in the: A. Cytoplasm B. Chloroplast C. Mitochondrial matrix D. Thylakoid membranes 17. What is the final electron acceptor in the electron transport chain? A. Carbon dioxide B. Water C. Oxygen D. Glucose

## Step1<br />The Krebs cycle, also known as the citric acid cycle or the tricarboxylic acid cycle, is a series of chemical reactions that generates energy through the oxidation of acetyl-CoA. This process takes place in the mitochondrial matrix, which is the space within the inner membrane of a mitochondrion. The Krebs cycle does not occur in the cytoplasm, chloroplast, or thylakoid membranes.<br /><br />## Step2<br />The electron transport chain is the final stage of cellular respiration, where the energy from electrons transferred from NADH and FADH2 is used to pump protons across the mitochondrial membrane, creating a proton gradient that drives ATP synthesis. The final electron acceptor in the electron transport chain is oxygen. Oxygen accepts the electrons after they have passed through the electron transport chain, combining with protons to form water. Carbon dioxide, water, and glucose are not the final electron acceptors in the electron transport chain.