BIO 205L MIDTERM 2025/2026 LAB QUESTIONS
AND ANSWERS/MICROBIOLOGY GRADED A+
Why do transient microbiota (flora) not become entrenched?
Come into contact with skin constantly, but most are unable to multiply there and
will die. pH of skin is usually acidic (ranging from 4-6). The epidermis (outer layer
of skin) has a low water content and is frequently dry, so normal skin flora is
associated with the apocrine and sebaceous glands in the skin which provide not
only moisture, but also other nutrients for microbial growth. Washing skin with
soap and water sloughs off dead outermost layers of skin and may expose normal
flora.
Person safety
Ø Lab coat or apron
Ø Gloves
Ø Safety glasses
Ø Closed toe and covered heel shoes
Ø Hair should be tied up
disposal - Microscope slides
white paper biohazard discard pouches or the red plastic biohazard boxes
,disposal - broken glass
white paper biohazard discard pouches or the red plastic biohazard boxes
disposal - petri dishes
orange/red biohazard trash bags in the white metal cans with foot pedal to open
disposal - plastic tubes
orange/red biohazard trash bags in the white metal cans with foot pedal to open
disposal - paper trash contaminated with microbial culture
orange/red biohazard trash bags in the white metal cans with foot pedal to open
disposal - tube and flask media
plastic discard tubs on the bottom of the cart, use racks for tubes, remove all labels
disease-causing for humans
pathogenic
,Handwashing procedure
1. Turn on faucet and preferably adjust temperature to warm.
2. Wet hands and apply soap.
3. Rub hands vigorously and scrub all surfaces and nails.
4. 10-15 seconds
5. Rinse well and dry hands. Use paper towel to turn off faucet.
hospital-acquired infections
Nosocomial
the number of microorganisms or viruses sufficient to establish an infection
inefectious dose
establish themselves on or in the body, but do not produce disease under normal
conditions
Normal or resident microbiota (flora)
, diphtheroid Corynebacterium and Propionibacterium, species of Staphylococcus
such as Staphylococcus aureus and Staphylococcus epidermis, and Malassezia
yeast
Common resident microbes of the skin include...
may be present on the body temporarily but do not become firmly entrenched
Transient microbiota (flora)
the top 2 reasons for nosocomial infections in the US
Staphylococcus aureus and Pseudomonas aeruginosa
disposal - micropipette tips
plastic discard beakers on the bench tops or in the orange/red biohazard trash bags
in the white metal cans with foot pedal to open
disposal - swabs
plastic discard beakers on the bench tops or in the orange/red biohazard trash bags
in the white metal cans with foot pedal to open
AND ANSWERS/MICROBIOLOGY GRADED A+
Why do transient microbiota (flora) not become entrenched?
Come into contact with skin constantly, but most are unable to multiply there and
will die. pH of skin is usually acidic (ranging from 4-6). The epidermis (outer layer
of skin) has a low water content and is frequently dry, so normal skin flora is
associated with the apocrine and sebaceous glands in the skin which provide not
only moisture, but also other nutrients for microbial growth. Washing skin with
soap and water sloughs off dead outermost layers of skin and may expose normal
flora.
Person safety
Ø Lab coat or apron
Ø Gloves
Ø Safety glasses
Ø Closed toe and covered heel shoes
Ø Hair should be tied up
disposal - Microscope slides
white paper biohazard discard pouches or the red plastic biohazard boxes
,disposal - broken glass
white paper biohazard discard pouches or the red plastic biohazard boxes
disposal - petri dishes
orange/red biohazard trash bags in the white metal cans with foot pedal to open
disposal - plastic tubes
orange/red biohazard trash bags in the white metal cans with foot pedal to open
disposal - paper trash contaminated with microbial culture
orange/red biohazard trash bags in the white metal cans with foot pedal to open
disposal - tube and flask media
plastic discard tubs on the bottom of the cart, use racks for tubes, remove all labels
disease-causing for humans
pathogenic
,Handwashing procedure
1. Turn on faucet and preferably adjust temperature to warm.
2. Wet hands and apply soap.
3. Rub hands vigorously and scrub all surfaces and nails.
4. 10-15 seconds
5. Rinse well and dry hands. Use paper towel to turn off faucet.
hospital-acquired infections
Nosocomial
the number of microorganisms or viruses sufficient to establish an infection
inefectious dose
establish themselves on or in the body, but do not produce disease under normal
conditions
Normal or resident microbiota (flora)
, diphtheroid Corynebacterium and Propionibacterium, species of Staphylococcus
such as Staphylococcus aureus and Staphylococcus epidermis, and Malassezia
yeast
Common resident microbes of the skin include...
may be present on the body temporarily but do not become firmly entrenched
Transient microbiota (flora)
the top 2 reasons for nosocomial infections in the US
Staphylococcus aureus and Pseudomonas aeruginosa
disposal - micropipette tips
plastic discard beakers on the bench tops or in the orange/red biohazard trash bags
in the white metal cans with foot pedal to open
disposal - swabs
plastic discard beakers on the bench tops or in the orange/red biohazard trash bags
in the white metal cans with foot pedal to open
