micro 290 lab midterm\\\ MICR 290 Lab
Midterm 2025 – Study Guide & Practice
Questions
what does PPE mean?
personal protective equipment
what does PPE include?
includes but is not limited to lab coats, chemical aprons (if needed), and face masks
what are the general most important safety habits when working in lab?
do not touch face & mouth, disinfect your workplace (with 70% alcohol), wash hands frequently even
when wearing gloves
what is type of microscope did you observe in the video?
compound binocular light microscope
what is the magnification power of the compound microscope at 40X objective and 100X objective lens
power?
the total magnification power of the compound microscope at 40X is 400X and the total magnification
power of the compound microscope at 100X is 1000X
if a bacterium is 2 micrometers long, how many millimeters long does it appear under the 40X objective
lens? how many millimeters long does it appear under the oil immersion lens?
the bacterium is 0.8mm long under 40X objective lens and 2mm long under the oil immersion lens
(show work on this question)
- 2micro x 400 = 800 micro (0.8mm)
- 2 micro x 1000 = 2000 micro (2mm)
staphylococcus aureus
bacillus cereus
spirillum volutans
saccharomyces cerevisiae
what is the meaning of aseptic technique?
without contamination technique
what does the word inoculation mean?
, the process of transferring the microbes from one medium to another
what does the word inoculum mean?
refers to the actual bacteria
what is the commonly used tool for bacterial inoculation?
wire loop
what does the word sterilizing mean?
free of any types of germ; germ free
how are wire loops sterilized in the lab?
held under flame until red hot, waiting 30-45 seconds to cool the wire loop
what is the main purpose of isolation streak plate?
to separate individual bacteria from a mixture of bacteria
what is the definition of bacterial colony?
grows on the surface of solid media. colony: visible mass of microorganisms all originating from a single
mother cell
find and display pictorial examples of isolation streak plates from internet that shows mixture of
bacteria separated into discrete colonies
what is the meaning of bacterial smearing?
thin layer of bacteria placed on a slide
what is the net electric charge on all biological membranes?
net negative charge
what type of stains are mostly used for making bacterial staining techniques?
basic stain (have a net positive charge)
what are 3 broad categories of staining techniques used in the laboratory?
simple stain, differential stain, & structural stain
what is simple staining and what is the main advantage of it?
simple staining uses only one dye or stain and only allows you to observe the shape of bacteria and their
arrangement
what are the 3 most common shapes of bacteria?
bacillus (rod, oblong)
coccus (sphere)
Midterm 2025 – Study Guide & Practice
Questions
what does PPE mean?
personal protective equipment
what does PPE include?
includes but is not limited to lab coats, chemical aprons (if needed), and face masks
what are the general most important safety habits when working in lab?
do not touch face & mouth, disinfect your workplace (with 70% alcohol), wash hands frequently even
when wearing gloves
what is type of microscope did you observe in the video?
compound binocular light microscope
what is the magnification power of the compound microscope at 40X objective and 100X objective lens
power?
the total magnification power of the compound microscope at 40X is 400X and the total magnification
power of the compound microscope at 100X is 1000X
if a bacterium is 2 micrometers long, how many millimeters long does it appear under the 40X objective
lens? how many millimeters long does it appear under the oil immersion lens?
the bacterium is 0.8mm long under 40X objective lens and 2mm long under the oil immersion lens
(show work on this question)
- 2micro x 400 = 800 micro (0.8mm)
- 2 micro x 1000 = 2000 micro (2mm)
staphylococcus aureus
bacillus cereus
spirillum volutans
saccharomyces cerevisiae
what is the meaning of aseptic technique?
without contamination technique
what does the word inoculation mean?
, the process of transferring the microbes from one medium to another
what does the word inoculum mean?
refers to the actual bacteria
what is the commonly used tool for bacterial inoculation?
wire loop
what does the word sterilizing mean?
free of any types of germ; germ free
how are wire loops sterilized in the lab?
held under flame until red hot, waiting 30-45 seconds to cool the wire loop
what is the main purpose of isolation streak plate?
to separate individual bacteria from a mixture of bacteria
what is the definition of bacterial colony?
grows on the surface of solid media. colony: visible mass of microorganisms all originating from a single
mother cell
find and display pictorial examples of isolation streak plates from internet that shows mixture of
bacteria separated into discrete colonies
what is the meaning of bacterial smearing?
thin layer of bacteria placed on a slide
what is the net electric charge on all biological membranes?
net negative charge
what type of stains are mostly used for making bacterial staining techniques?
basic stain (have a net positive charge)
what are 3 broad categories of staining techniques used in the laboratory?
simple stain, differential stain, & structural stain
what is simple staining and what is the main advantage of it?
simple staining uses only one dye or stain and only allows you to observe the shape of bacteria and their
arrangement
what are the 3 most common shapes of bacteria?
bacillus (rod, oblong)
coccus (sphere)
