Catabolic metabolism refers to chemical reactions that break down complex molecules into simpler molecules. True False Question 20 (2 points) Which of the following microbes is a Photoautotroph? Escherichia coli Helicobacter pylori Cyanobacteria All of the above Question 21 (2 points) Lactic acid fermentation is common metabolic pathway in certain bacteria as well as human muscle cells under aerobic conditions. True False.