2026 QUESTIONS WITH CORRECT ANSWERS
◉ A;
Conversion of only the slant to a pink color in a Christensen's urea agar
slant is produced by bacterial species that have weak urease activity. The
reaction in the slant to the right is often produced by Klebsiella species,
as an example. Strong urease activity is indicated by conversion of the
slant and the butt of the tube to a pink color, as seen in the tube to the
left. The slant only reaction in the right tube may be seen early on if only
the slant had been inoculated; however, with a strong urease producer,
both the slant and the butt would turn. Therefore, the reaction is
dependent on the strength of urease activity. If the media had outdated
for a prolonged period, either there would be no reaction or the
appearance of only a faint pink tinge, either in the slant, the butt or both,
again depending on the strength of urease production by the unknown
organism.. Answer: The urease reaction seen in the Christensen's urea
agar slant on the far right indicates:
A. Weak activity
B. Strong activity
C. Slant only inoculated
D. Use of outdated medium
◉ D;
,The steps in the PCR process are:
1. Denaturation (Turning double stranded DNA into single strands.)
2. Annealing/Hybrization (Attachment of primers to the single DNA
strands.)
3. Extension (Creating the complementary strand to produce new double
stranded DNA.). Answer: What is the first step of the PCR reaction?
A. Hybridization
B. Extension
C. Annealing
D. Denaturation
◉ B;
Isotonic or normal saline is a 0.85 % solution of sodium chloride in
water.. Answer: The concentration of sodium chloride in an isotonic
solution is :
A. 8.5 %
B. 0.85 %
C. 0.08 %
D. 1 molar
◉ C;
,In DIC, or disseminated intravascular coagulation, the prothrombin time
is increased due to the consumption of the coagulation factors due to the
tiny clots forming throughout the vasculature. This is also the reason that
the fibrinogen levels and platelet levels are decreased. Finally FDP, or
fibrin degredation products, are increased due to the formation and
subsequent dissolving of many tiny clots in the vasculature. The FDPs
are the pieces of fibrin that are left after the fibrinolytic processes take
place.. Answer: Which of the following laboratory results would be seen
in a patient with acute Disseminated Intravascular Coagulation (DIC)?
A. prolonged PT, elevated platelet count, decreased FDP
B. normal PT, decreased fibrinogen, decreased platelet count, decreased
FDP
C. prolonged PT, decreased fibrinogen, decreased platelet count,
increased FDP
D. normal PT, decreased platelet count, decreased FDP
◉ B;
A dilution commonly used for a routine sperm count is a 1:20.. Answer:
A dilution commonly used for a routine sperm count is:
A. 1:2
B. 1:20
C. 1:200
D. 1:400
, ◉ B;
Prozone effect (due to antibody excess) will result in an initial false
negative in spite of the large amount of antibody in the serum, followed
by a positive result as the specimen is diluted.. Answer: The prozone
effect ( when performing a screening titer) is most likely to result in:
A. False positive
B. False negative
C. No reaction at all
D. Mixed field reaction
◉ A;
One of the key characteristics to the identification of Nocardia asteroides
is its inability to hydrolyze casein, tyrosine or xanthine, as shown in this
photograph. Nitrates are reduced to nitrites. Both Nocardia brasiliensis
and Actinomadura madurae hydrolyze both casein and tyrosine;
Streptomyces griseus hydrolyzes all three of the substrates.. Answer:
Illustrated in this photograph is an agar quadrant plate containing casein
(A), tyrosine (B), nitrate (C) and xanthine (D). None of the substrates
have been hydrolyzed and nitrate has been reduced. The most likely
identification is:
A. Nocardia asteroides
B. Nocardia brasiliensis