The krebs cycle for questions 4–7, write true if the statement is true. if the statement is false, change the underlined word or words to make the statement true. 4. the pyruvic acid produced in glycolysis enters the chloroplasts if oxygen is present in a cell. 5. in the matrix, pyruvic acid is converted to lactic acid before the krebs cycle begins. 6. the compound that joins with a 4-carbon molecule in the krebs cycle is called acetyl-coa. 7. carbon dioxide is the only product of the krebs cycle that is not re- used or used in other stages of cellular respiration.