MBIO 3812 Exam 3 with Questions and
Correct Answers Latest Updated 2025-
2026 GRADED A+
coliform ,can ,ferment... ,- ,CORRECT ,ANSWER-lactose
what ,does ,the ,presence ,of ,coliforms ,indicate? ,- ,CORRECT ,ANSWER-whether ,a
,water ,sample ,has ,been ,contaminated ,with ,fecal ,matter
what ,is ,used ,to ,determine ,if ,a ,water ,sample ,is ,contaminated ,with ,coliforms? ,-
,CORRECT ,ANSWER-Most ,Probable ,Number ,(MPN) ,test
MPN ,calculates... ,- ,CORRECT ,ANSWER-1. ,total ,coliform ,counts
2. ,E. ,coli ,counts
what ,was ,the ,objective ,of ,our ,MPN? ,- ,CORRECT ,ANSWER-whether ,duck ,pond
,water ,was ,contaminated ,with ,E. ,coli ,(coliform)
LTB ,- ,CORRECT ,ANSWER-Lauryl ,Tryptose ,Broth
LTB ,contains ,- ,CORRECT ,ANSWER-1. ,Lauryl ,sulfate: ,inhibits ,growth ,of ,non-
coliforms
2. ,lactose: ,coliforms ,can ,ferment ,this
3. ,Durham ,tube: ,indicates ,lactose ,fermentations
LTB ,is... ,- ,CORRECT ,ANSWER-selective ,for ,coliforms ,and ,gives ,a
,PRESUMPTIVE ,determination ,for ,their ,presence
after ,first ,incubation ,period, ,LTB ,broths ,in ,MPN ,are ,examined ,for ,what ,two
,things? ,- ,CORRECT ,ANSWER-1. ,growth ,(considered ,+ ,for ,later ,calculations)
2. ,gas ,bubble
, indicate ,PROBABLE ,coliform
2 ,loops ,of ,culture ,from ,every ,+ ,(growth) ,LTB ,tube ,goes ,into... ,- ,CORRECT
,ANSWER-1. ,Brilliant ,Green ,Lactose ,Bile ,broth ,(BGLB)
2. ,E. ,coli ,broth ,(EC)
Brilliant ,Green ,Lactose ,Bile ,broth ,contains ,- ,CORRECT ,ANSWER-1. ,Lactose:
,fermentable ,by ,coliforms
2. ,Durham ,tube: ,gas ,indicates ,lactose ,fermentation ,(+ ,result ,if ,gas)
3. ,2% ,bile: ,selective ,for ,coliforms
why ,is ,BGLB ,important? ,- ,CORRECT ,ANSWER-it ,is ,selective ,& ,CONFIRMS
,presence ,of ,coliforms
3 ,E. ,coli ,broth ,components ,- ,CORRECT ,ANSWER-1. ,Lactose: ,fermentable ,by
,coliforms
2. ,Durham ,tube: ,gas ,indicates ,lactose ,fermentation ,(+ ,result)
3. ,bile ,salts: ,selective ,for ,coliforms
how ,is ,EC ,broth ,selective ,for ,E. ,coli? ,- ,CORRECT ,ANSWER-when ,incubated ,at
,45°C
P ,value ,in ,MPN? ,- ,CORRECT ,ANSWER-P ,= ,total ,# ,of ,+ ,BGLB ,OR ,EC
Vn ,value ,in ,MPN? ,- ,CORRECT ,ANSWER-Vn ,= ,combined ,volume ,of ,sample ,in
,LTB ,tubes ,that ,produced ,- ,BGLB ,or ,EC
Va ,value ,in ,MPN? ,- ,CORRECT ,ANSWER-Va ,= ,combined ,volume ,of ,sample ,in ,all
,LTB ,tubes
MPN ,calculation ,- ,CORRECT ,ANSWER-MPN/100 ,ml ,= ,100P ,÷ ,√(VnVa)
selective ,media ,- ,CORRECT ,ANSWER-contains ,compounds ,that ,can ,prevent ,the
,growth ,of ,certain ,bacterial ,species
how ,is ,media ,selective? ,- ,CORRECT ,ANSWER-inhibitors
differential ,media ,- ,CORRECT ,ANSWER-distinguishes ,between ,different
,bacterial ,species
two ,important ,components ,of ,differential ,media ,- ,CORRECT ,ANSWER-1.
,substrates ,(only ,certain ,bacterial ,species ,can ,utilize)
2. ,indicators ,(visible ,indicator ,of ,substrate's ,differentiation)
coliforms ,- ,CORRECT ,ANSWER--reside ,in ,guts ,of ,birds ,and ,mammals
Correct Answers Latest Updated 2025-
2026 GRADED A+
coliform ,can ,ferment... ,- ,CORRECT ,ANSWER-lactose
what ,does ,the ,presence ,of ,coliforms ,indicate? ,- ,CORRECT ,ANSWER-whether ,a
,water ,sample ,has ,been ,contaminated ,with ,fecal ,matter
what ,is ,used ,to ,determine ,if ,a ,water ,sample ,is ,contaminated ,with ,coliforms? ,-
,CORRECT ,ANSWER-Most ,Probable ,Number ,(MPN) ,test
MPN ,calculates... ,- ,CORRECT ,ANSWER-1. ,total ,coliform ,counts
2. ,E. ,coli ,counts
what ,was ,the ,objective ,of ,our ,MPN? ,- ,CORRECT ,ANSWER-whether ,duck ,pond
,water ,was ,contaminated ,with ,E. ,coli ,(coliform)
LTB ,- ,CORRECT ,ANSWER-Lauryl ,Tryptose ,Broth
LTB ,contains ,- ,CORRECT ,ANSWER-1. ,Lauryl ,sulfate: ,inhibits ,growth ,of ,non-
coliforms
2. ,lactose: ,coliforms ,can ,ferment ,this
3. ,Durham ,tube: ,indicates ,lactose ,fermentations
LTB ,is... ,- ,CORRECT ,ANSWER-selective ,for ,coliforms ,and ,gives ,a
,PRESUMPTIVE ,determination ,for ,their ,presence
after ,first ,incubation ,period, ,LTB ,broths ,in ,MPN ,are ,examined ,for ,what ,two
,things? ,- ,CORRECT ,ANSWER-1. ,growth ,(considered ,+ ,for ,later ,calculations)
2. ,gas ,bubble
, indicate ,PROBABLE ,coliform
2 ,loops ,of ,culture ,from ,every ,+ ,(growth) ,LTB ,tube ,goes ,into... ,- ,CORRECT
,ANSWER-1. ,Brilliant ,Green ,Lactose ,Bile ,broth ,(BGLB)
2. ,E. ,coli ,broth ,(EC)
Brilliant ,Green ,Lactose ,Bile ,broth ,contains ,- ,CORRECT ,ANSWER-1. ,Lactose:
,fermentable ,by ,coliforms
2. ,Durham ,tube: ,gas ,indicates ,lactose ,fermentation ,(+ ,result ,if ,gas)
3. ,2% ,bile: ,selective ,for ,coliforms
why ,is ,BGLB ,important? ,- ,CORRECT ,ANSWER-it ,is ,selective ,& ,CONFIRMS
,presence ,of ,coliforms
3 ,E. ,coli ,broth ,components ,- ,CORRECT ,ANSWER-1. ,Lactose: ,fermentable ,by
,coliforms
2. ,Durham ,tube: ,gas ,indicates ,lactose ,fermentation ,(+ ,result)
3. ,bile ,salts: ,selective ,for ,coliforms
how ,is ,EC ,broth ,selective ,for ,E. ,coli? ,- ,CORRECT ,ANSWER-when ,incubated ,at
,45°C
P ,value ,in ,MPN? ,- ,CORRECT ,ANSWER-P ,= ,total ,# ,of ,+ ,BGLB ,OR ,EC
Vn ,value ,in ,MPN? ,- ,CORRECT ,ANSWER-Vn ,= ,combined ,volume ,of ,sample ,in
,LTB ,tubes ,that ,produced ,- ,BGLB ,or ,EC
Va ,value ,in ,MPN? ,- ,CORRECT ,ANSWER-Va ,= ,combined ,volume ,of ,sample ,in ,all
,LTB ,tubes
MPN ,calculation ,- ,CORRECT ,ANSWER-MPN/100 ,ml ,= ,100P ,÷ ,√(VnVa)
selective ,media ,- ,CORRECT ,ANSWER-contains ,compounds ,that ,can ,prevent ,the
,growth ,of ,certain ,bacterial ,species
how ,is ,media ,selective? ,- ,CORRECT ,ANSWER-inhibitors
differential ,media ,- ,CORRECT ,ANSWER-distinguishes ,between ,different
,bacterial ,species
two ,important ,components ,of ,differential ,media ,- ,CORRECT ,ANSWER-1.
,substrates ,(only ,certain ,bacterial ,species ,can ,utilize)
2. ,indicators ,(visible ,indicator ,of ,substrate's ,differentiation)
coliforms ,- ,CORRECT ,ANSWER--reside ,in ,guts ,of ,birds ,and ,mammals
