BIO 205 LAB MIDTERM EXAM STUDY GUIDE
UPDATED ACTUAL QUESTIONS AND CORRECT
ANSWERS
Question 1.
significance of flaming inoculating loop/wire before and after each inoculation
ANSWER
to sterilize and prevent cross contamination
Question 2.
ubiquity
ANSWER
the state of being everywhere at once
Question 3.
high- and dry- power objective lens
ANSWER
magnifies about 40x
Question 4.
medical importance of gram staining
ANSWER
can determine presence of bacteria in a sample as well as differentiate between 2 species
HELP CHOOSE APPROPRIATE ANTIBIOTIC FOR TREATMENT
Question 5.
Magnification
ANSWER
the ability of a lens to enlarge an object
-ocular lens: 10x
-objective lens: 4x, 10x, 40x, 100x
,Question 6.
Positive staining
ANSWER
microorganisms appear colored against a clear background (basic/cationic dyes)
Question 7.
nutrient broth tubes
ANSWER
contain mineral nutrients dissolved in distilled water and sterilized in autoclave
Question 8.
aseptic techniques
ANSWER
procedures that reduce the risk of unwanted microbes present in the air, bodies, and other lab
equipment from contaminating our cultures or infecting us
Question 9.
significance of holding the test tube caps in the (pinky)
ANSWER
to allow for quick/ easy access to put the cap back on and to prevent it from getting
contaminated by touching other surfaces
Question 10.
various differential staining methods
ANSWER
i. gram negative
ii. gram positive
iii. acid-fast stain
, Question 11.
sterilization
ANSWER
done so that no living microbial forms are present (including endospores and viruses)
Question 12.
ocular lens
ANSWER
Eyepiece of a microscope; magnifies the image (10x)
Question 13.
endospore
ANSWER
dormant cell; resistant to heat, dessication, chemicals, and radiation
Question 14.
Gram staining steps
ANSWER
1. prepare smear (heat fix)
2. place slide in staining rack
3. cover smear with crystal violet stain (let sit 1-2 min)
4. gently wash with distilled water
5. cover smear with iodine (let sit 1-2 min)
6. rinse with distilled water, drain excess water
7. decolorize by washing slide with alcohol for 2-3 seconds
8. immediatly rinse with distilled water to remove alcohol
9. drain exces water
10. cover smear with safranin (let sit 1-2 min)
11. rinse with distilled water
12. blot slide with bitulous paper and allow to air dry
13. examine
UPDATED ACTUAL QUESTIONS AND CORRECT
ANSWERS
Question 1.
significance of flaming inoculating loop/wire before and after each inoculation
ANSWER
to sterilize and prevent cross contamination
Question 2.
ubiquity
ANSWER
the state of being everywhere at once
Question 3.
high- and dry- power objective lens
ANSWER
magnifies about 40x
Question 4.
medical importance of gram staining
ANSWER
can determine presence of bacteria in a sample as well as differentiate between 2 species
HELP CHOOSE APPROPRIATE ANTIBIOTIC FOR TREATMENT
Question 5.
Magnification
ANSWER
the ability of a lens to enlarge an object
-ocular lens: 10x
-objective lens: 4x, 10x, 40x, 100x
,Question 6.
Positive staining
ANSWER
microorganisms appear colored against a clear background (basic/cationic dyes)
Question 7.
nutrient broth tubes
ANSWER
contain mineral nutrients dissolved in distilled water and sterilized in autoclave
Question 8.
aseptic techniques
ANSWER
procedures that reduce the risk of unwanted microbes present in the air, bodies, and other lab
equipment from contaminating our cultures or infecting us
Question 9.
significance of holding the test tube caps in the (pinky)
ANSWER
to allow for quick/ easy access to put the cap back on and to prevent it from getting
contaminated by touching other surfaces
Question 10.
various differential staining methods
ANSWER
i. gram negative
ii. gram positive
iii. acid-fast stain
, Question 11.
sterilization
ANSWER
done so that no living microbial forms are present (including endospores and viruses)
Question 12.
ocular lens
ANSWER
Eyepiece of a microscope; magnifies the image (10x)
Question 13.
endospore
ANSWER
dormant cell; resistant to heat, dessication, chemicals, and radiation
Question 14.
Gram staining steps
ANSWER
1. prepare smear (heat fix)
2. place slide in staining rack
3. cover smear with crystal violet stain (let sit 1-2 min)
4. gently wash with distilled water
5. cover smear with iodine (let sit 1-2 min)
6. rinse with distilled water, drain excess water
7. decolorize by washing slide with alcohol for 2-3 seconds
8. immediatly rinse with distilled water to remove alcohol
9. drain exces water
10. cover smear with safranin (let sit 1-2 min)
11. rinse with distilled water
12. blot slide with bitulous paper and allow to air dry
13. examine
