Transcript Microbial Growth Active Lecture Slides

Active Lecture
Questions
Chapter 6
Microbial Growth
Copyright © 2010 Pearson Education, Inc.
Two culture media were inoculated with four
different bacteria. After incubation, the
following results were obtained:
Medium 1 is
a. selective.
b. differential.
c. both selective and differential.
Medium 2 is
a. selective.
b. differential.
c. both selective and differential.
Which of the lines best depicts the log
phase of a thermophile incubated at
room temperature?
a
b
c
Which of the lines best depicts the log
phase of Listeria monocytogenes (a
mesophile) growing in a human?
a
b
c
Assume you inoculated 100 facultatively anaerobic
cells onto nutrient agar and incubated the plate
aerobically. You then inoculated 100 cells of the
same species onto nutrient agar and incubated the
second plate anaerobically. After incubation for 24
hours, you should have
a. more colonies on the aerobic plate.
b. more colonies on the anaerobic plate.
c. the same number of colonies on both plates.
The term trace elements refers to
a.
b.
c.
d.
e.
the elements CHONPS.
vitamins.
nitrogen, phosphorus, and sulfur.
small mineral requirements.
toxic substances.
Which one of the following temperatures
would most likely kill a mesophile?
a.
b.
c.
d.
e.
32OC
0°C
9°C
37°C
60°C
Which of the following is not a
characteristic of biofilms?
a.
b.
c.
d.
promotes antibiotic resistance
forming slimes
causes iron deficiency
use of quorum sensing
Which of the following types of media
would not be used to culture aerobes?
a.
b.
c.
d.
e.
selective media
reducing media
enrichment media
differential media
complex media
The optimum pH for most bacteria is
a.
b.
c.
d.
1
5
7
9
Organisms that require higher than
normal salt concentrations for growth are
called
a.
b.
c.
d.
Halogens
Extreme halophiles
Facultative halophiles
Microhalophiles
In food preservation, salts and sugars
are used because they create a
a.
b.
c.
d.
Lower pH
Hypertonic environment
Hypotonic environment
Lower osmotic pressure
Chemoautotrophs and photoautotrophs
derive their carbon from
a.
b.
c.
d.
Carbon dioxide
Proteins
Lipids
Carbohydrates
An organism that uses oxygen but can
grow without oxygen is called a(n)
a.
b.
c.
d.
Obligate aerobe
Facultative anaerobe
Aerobe
Obligate anaerobe
Generation time can best be defined as
a.
b.
c.
d.
The length of time it takes for lag phase
The duration of log phase
The length of time it takes for a cell to divide
The minimum rate of doubling
Capnophiles must be grown in high
concentrations of
a.
b.
c.
d.
Oxygen
Salt
Glucose
Carbon dioxide
The culture medium that is designed to
suppress unwanted microbes while
encouraging desired microbes is called
a.
b.
c.
d.
Complex
Selective
Reducing
Differential
To neutralize acids as they are produced
in a culture, what should be added to the
culture medium?
a.
b.
c.
d.
Buffers
Salts
Sugars
PABA
What can be added to a liquid medium
when it is desirable to grow bacteria on a
solid medium?
a.
b.
c.
d.
Glucose
Magnesium sulfate
Potassium phosphate
Agar
A spectrophotometer can be used to
measure
a.
b.
c.
d.
Metabolic activity
Turbidity
Dry weight
Pathogenicity
Which method is utilized to ensure that
plates containing 25 to 250 colonies are
counted?
a.
b.
c.
d.
The most probable number method
Serial dilution
Filtration
Spread plate method