BIOL 250 Exam 1 Questions with 100% Correct Answers

Binary Fission Correct Answer Cell division in bacteria in which one cell divides into two cells Why do bacterial cells not undergo mitosis and meiosis? Correct Answer 1) Prokaryotic cells do not possess the machinery to produce spindle fibers and therefore cannot move chromosomes around in the cell 2) Replication of DNA in a prokaryote does not occur in one phase, but instead occurs continuously 3) Most bacteria have only one circular chromosome that is attached to the cell membrane Bacteria undergo four different phases of growth. These phases, in order, are: Correct Answer Lag, log, stationary, death Which of the following can influence the length of the lag phase of growth? Correct Answer 1) Conditions of the new media that bacteria is transferred to 2) Conditions of the old media that bacteria is transferred from 3) Characteristics of the individual organism A culture of E. Coli contains 1000 cells/ml with a generation time of 30 minutes. How many organisms would be present after a period of 2 hours? Correct Answer 16,000 cells/ml Why is it impossible for a culture of bacteria, in a single tube, to remain in the log phase of the growth cycle forever? Correct Answer 1) Nutrients in the media are depleted as the number of bacteria increase 2) Metabolic wastes accumulate as the number of bacteria increase 3) Space is limited as the number of bacteria increase 4) Metabolic wastes accumulate and space is limited as the number of bacteria increases Bacterial growth is measured by estimating Correct Answer The number of viable cells per milliliter of culture Which of the following techniques rely on the concept that under the proper conditions, only living bacteria will divide and form a visible colony on agar? Correct Answer Standard plate count and serial dilution Which type of bacteria can grow at low temperatures (below 25°C)? Correct Answer Psychrophiles E. Coli is a bacteria that can grow in the presence or absence of oxygen, which would classify it as a/an Correct Answer Facultative anaerobe