IMViC- quiz 4

Question 1

IMViC series

Answer 1

• indole
• methyl red
• voges-proskauer
• doesnt matter
• citrate

Question 2

indole
enzyme
molecular mechanism
media

Answer 2

•tryptophanase
•aa (tryptophan) —> pyruvate, —> nh3
—> indole-accumulates + Kovac’s reagent (add 5 drops, wait)=cherry red on top +. negative: no color change.
•tryptophan broth, tryptone broth (SIM used for this test).

Question 3

methyl red
enzyme
molecular mechanism
media

Answer 3

• mixed acid fermentation
• add 5 drops methyl red ph indicator, mix. red +(ph 4). yellow (orange) -(ph 6).
• mr broth and mr-vp broth (glucose)

Question 4

VP
enzyme
molecular mechanism
media

Answer 4

• 2,3-butanediol fermentation
• LOOK ON PAPER. red-positive. negative-copper.
• mr broth and mr-vp broth (glucose)

Question 5

citrate
enzyme
molecular mechanism
media

Answer 5

• citrate permease
• transports into cytoplasm–> respiration (glyalysist TCA)–>co2–> no bicarbonate bapic
• bromothymol blue green (neg)–>blue (pos) no additional reagents added.

Question 6

phenylalanine deamination
enzyme
molecular mechanism
media

Answer 6

•phe. deaminase
LOOK AT PAPER
fecl3 (5 drops)–> green color=positive. yellow=negative.
•phe slants

Question 7

urease
enzyme
molecular mechanism
media

Answer 7

• urease
• release nh3 (nh4+, basic) indicator is phenol red which turns from red–> pink (pos). >8.1 ph.
• urea slants

Question 8

nitrate
enzyme
molecular mechanism
media

Answer 8

•can organism use no3 as term. e- acceptor (anaerobic resp).
•LOOK AT PAPER. after adding reagent a and b, red=nitrite. zinc turns nitrate –> nitrite.
after adding zinc if its red, not capable of nitrate reduction. if not red, ammonia or n2 (was there gas?)
•nitrate broth + food