BIO 250 Microbiology Final Exam Questions With Correct Answers Latest Update 2023/2024 Graded A+

1. In the nitrogen cycle, which of the following steps involves removal of nitrogen from the atmosphere by bacteria? a. Ammonification b. Denitrification c. Nitrification d. Nitrogen fixation Answer is d. In nitrogen fixation, nitrogen is removed from the atmosphere by nitrogen-fixing bacteria and converted to ammonia 2. If enough H+ ions are added to pure water to raise the H+ concentration of the solution to ten times higher than the original concentration, what is the resulting OH- concentration of the solution? a. 10-5 M b. 10-6 M c. 10-7 M d. 10-8 M Answer is d. The H+ concentration would be 10-6 M, resulting in the OH- being 10-8 M 3. Fungi are able to reproduce asexually by creating conidiospores and sponrangiospores. Which of the following is an accurate explanation for why it is advantageous that they are also capable of sexual reproduction? a. Asexually produced offspring are more likely to compete for resources and will kill off the parental fungi b. Fungi normally produce sexually but produce asexually in harsh conditions such as severe drought c. Offspring from two parents may have variations in form and function that contribute to survival of the species. d. Sexual reproduction produces more offspring at a faster rate than spore formation Answer is c. Sexually produced offspring have traits from both parents and may develop variations that give them an advantage for survival. 4. In a laboratory bacterial cell culture that had been infected by a virus, plaques are areas in which a. Bacterial cells are resistant to the virus and have not been infected b. There is no nutrient available for the bacteria to grow c. The virus has spread and left behind the remains of dead cells d. The virus has not yet spread to the area of cells Answer is c. Plaques are areas in which the bacteria have been destroyed by the virus and all that remain are dead cells 5. The sun’s energy is delivered as discrete packets that travel as waves and are called a. ATP b. Carotenoids c. NADP d. Photons Answer is d.