MICRO 020 LAB EXAM #1 QUESTIONS WELL ANSWERED LATEST UPDATE 2025/2026
Aseptic technique includes...
(a) sterilization of transfer tools before and after use
(b) disinfection of bench tops
(c) washing hands
(d) all of the above - Answers (d) all of the above
Placing the cap of a broth cultures up on the bench top is acceptable
True/False? - Answers False
Why is it important to allow the inoculating loop to cool prior to obtaining the inoculum? -
Answers to avoid frying the cell
A pure culture can be prepared from a mixed broth or a mixed agar slant culture directly
True/False - Answers False
Which of the following is a benefit of using the streak plate method for obtaining isolated
colonies compared to the pour plate method?
(a) the streak plate method allows you to observe colonies on the surface and deep in the agar
(b) the pour plate method does not require serial dilutions
(c) the streak plate method requires serial dilutions
(d) the streak plate method does not require serial dilutions - Answers (d) the streak plate
method does not require serial dilutions
When preparing a streak plate, it is important to only flame the loop before collecting a bacterial
sample, not for every subsequent streak
True / False? - Answers False
What is a bacterial colony? - Answers a collection of bacterial cells that arose from a single cell
Why is the use of oil immersion important when the 100x objective lens is in place? - Answers it
allows more light rays to enter directly into the objective lens to produce a clearer image
Which part of the microscope magnifies the specimen at various magnifications? - Answers
objective lens
The ability to distinguish between two distinct points, which determines clarity of an image, is
, known as... - Answers resolving power
What property of the microscopes used in lab allows us to maintain coarse focus at 400x total
magnification after having obtained focus a the lowest power objective? - Answers parfocal
When looking through the ocular lens, you will see... - Answers the field of views
Which of the following is/are important when preparing a bacterial smear?
(a) thin smears
(b) complete air-drying prior to heat fixation
(c) cleaning slides
(d) all of the above - Answers all of the above
Mesophiles have an optimum growth temperature at around...
(a) 25 C
(b) 37 C
(c) 60 C
(d) 100 C - Answers (b) 37 C
Bacterial that are incubated below their optimum growth temperature would... - Answers exhibit
decreased growth rates
Organisms that will only grow at temperatures above 50 C are classified as... - Answers obligate
thermophiles
Which part of the following buffer systems is more likely to act like a weak base?
(a) K2HPO4
(b) KH2PO4
(c) H+
(d) OH- - Answers (a) K2HPO4
Proteins can act as natural buffers because of their amphoteric nature
True/False - Answers True
The carboxyl end (-COOH) of amino acids are more likely to act like...
(a) a weak base
Aseptic technique includes...
(a) sterilization of transfer tools before and after use
(b) disinfection of bench tops
(c) washing hands
(d) all of the above - Answers (d) all of the above
Placing the cap of a broth cultures up on the bench top is acceptable
True/False? - Answers False
Why is it important to allow the inoculating loop to cool prior to obtaining the inoculum? -
Answers to avoid frying the cell
A pure culture can be prepared from a mixed broth or a mixed agar slant culture directly
True/False - Answers False
Which of the following is a benefit of using the streak plate method for obtaining isolated
colonies compared to the pour plate method?
(a) the streak plate method allows you to observe colonies on the surface and deep in the agar
(b) the pour plate method does not require serial dilutions
(c) the streak plate method requires serial dilutions
(d) the streak plate method does not require serial dilutions - Answers (d) the streak plate
method does not require serial dilutions
When preparing a streak plate, it is important to only flame the loop before collecting a bacterial
sample, not for every subsequent streak
True / False? - Answers False
What is a bacterial colony? - Answers a collection of bacterial cells that arose from a single cell
Why is the use of oil immersion important when the 100x objective lens is in place? - Answers it
allows more light rays to enter directly into the objective lens to produce a clearer image
Which part of the microscope magnifies the specimen at various magnifications? - Answers
objective lens
The ability to distinguish between two distinct points, which determines clarity of an image, is
, known as... - Answers resolving power
What property of the microscopes used in lab allows us to maintain coarse focus at 400x total
magnification after having obtained focus a the lowest power objective? - Answers parfocal
When looking through the ocular lens, you will see... - Answers the field of views
Which of the following is/are important when preparing a bacterial smear?
(a) thin smears
(b) complete air-drying prior to heat fixation
(c) cleaning slides
(d) all of the above - Answers all of the above
Mesophiles have an optimum growth temperature at around...
(a) 25 C
(b) 37 C
(c) 60 C
(d) 100 C - Answers (b) 37 C
Bacterial that are incubated below their optimum growth temperature would... - Answers exhibit
decreased growth rates
Organisms that will only grow at temperatures above 50 C are classified as... - Answers obligate
thermophiles
Which part of the following buffer systems is more likely to act like a weak base?
(a) K2HPO4
(b) KH2PO4
(c) H+
(d) OH- - Answers (a) K2HPO4
Proteins can act as natural buffers because of their amphoteric nature
True/False - Answers True
The carboxyl end (-COOH) of amino acids are more likely to act like...
(a) a weak base
