Transcript Chapter 6 Active Lecture Questions

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
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.
-50°C
0°C
9°C
37°C
60°C
Which of the following is not a
characteristic of biofilms?
a.
b.
c.
d.
antibiotic resistance
hydrogel
iron deficiency
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
An organism that has peroxidase and
superoxide dismutase but lacks catalase
is most likely an
a. aerobe.
b. aerotolerant anaerobe.
c. obligate anaerobe.
The optimum pH for most bacteria is
a.
b.
c.
d.
1
5
7
9
Organisms that require high salt
concentrations for growth are called
a.
b.
c.
d.
Halophiles
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 aerobe
Aerobe
Aerotolerant anaerobe
Biofilms reside in a matrix made up
primarily of
a.
b.
c.
d.
Lipids
Hydrogel
Proteins
Polysaccharides
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 medium when it
is desirable to grow bacteria on a solid
medium?
a.
b.
c.
d.
Glucose
Magnesium sulfate
Potassium phosphate
Agar
The source of nutrients in nutrient agar
is
a.
b.
c.
d.
Agar
Peptone and sodium chloride
Peptone and beef extract
Nutrient
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
Which of the following metabolic activities
can be used to measure microbial
growth?
a.
b.
c.
d.
Carbon dioxide consumption
Oxygen consumption
Glucose consumption
Salt consumption