OPENSTAX MICROBIOLOGY CHAPTER 9
EXAM PAPER WITH 100% CORRECT
SOLUTIONS AND RATIONALES FOR 2026.
⫸ Enrichment Media. Ans: encourages growth of desired microbe
that represent a fraction of the organisms present in an inoculation.
⫸ Selective Media. Ans: Inhibit growth of unwanted organisms and
support thee growth of organisms of interest.
⫸ Halotolerant. Ans: Do not need a high concentration of salt to
grow, but can still survive and divide in the presence of salt.
⫸ Halophiles. Ans: require high salt concentration for growth.
⫸ Thermophiles. Ans: Optimal temep 50c
important for biotechnology
⫸ Listeria monocytogens. Ans: Grows in refrigerators on/ in
-soft cheese
-deli meat
-hummus
, -ice cream
Does not harm humans but can cross the placenta of a pregnant
woman and kill the fetus.
Psychophile
⫸ Psychophiles. Ans: Cold loving, optimal temp at 15c
⫸ Mesophiles. Ans: Middle Loving, Optimal temp 20-45c
Most human pathogens.
Normal microbiota
⫸ Helicbactor pylori. Ans: neutrophile, survives in the stomach
because it creates a micro environment where the pH is nearly neutral.
Does it by urease with breaks down euro two form NH4+ and CO2
⫸ Alkaliphiles. Ans: grow optimally at pH above 8.5
⫸ Acidophiles. Ans: grow optimally at a pH of 5.5 or less.
EXAM PAPER WITH 100% CORRECT
SOLUTIONS AND RATIONALES FOR 2026.
⫸ Enrichment Media. Ans: encourages growth of desired microbe
that represent a fraction of the organisms present in an inoculation.
⫸ Selective Media. Ans: Inhibit growth of unwanted organisms and
support thee growth of organisms of interest.
⫸ Halotolerant. Ans: Do not need a high concentration of salt to
grow, but can still survive and divide in the presence of salt.
⫸ Halophiles. Ans: require high salt concentration for growth.
⫸ Thermophiles. Ans: Optimal temep 50c
important for biotechnology
⫸ Listeria monocytogens. Ans: Grows in refrigerators on/ in
-soft cheese
-deli meat
-hummus
, -ice cream
Does not harm humans but can cross the placenta of a pregnant
woman and kill the fetus.
Psychophile
⫸ Psychophiles. Ans: Cold loving, optimal temp at 15c
⫸ Mesophiles. Ans: Middle Loving, Optimal temp 20-45c
Most human pathogens.
Normal microbiota
⫸ Helicbactor pylori. Ans: neutrophile, survives in the stomach
because it creates a micro environment where the pH is nearly neutral.
Does it by urease with breaks down euro two form NH4+ and CO2
⫸ Alkaliphiles. Ans: grow optimally at pH above 8.5
⫸ Acidophiles. Ans: grow optimally at a pH of 5.5 or less.
