GTC MICROBIOLOGY ACTUAL TEST PAPER
2026 QUESTIONS WITH SOLUTIONS
GRADED A+
●● Catalase Test purpose.
Answer: Differential Test
To determine which bacteria has the catalase to breakdown hydrogen
peroxide into oxygen and water; also used to differentiate gram positive,
however many Gram negatives use catalase as well
●● Amylase Test.
Answer: 1. Obtain agar culture of bacteria
2. Obtain starch hydrolysis plate and on bottom of plate divide into two
sections
3. Label bacteria names on each side
4. Using an inoculation loop, zig zag a line of bacteria on each side.
5. Incubate at the plates upside down at 37 C remove in 24-24 hours.
On next lab
1. Place 1 ml of Lugol's Iodine solution onto the agar plate. Iodine will
cause starch to turn deep brown-black color if it is still present.
2. Look for a clearing in the agar around the bacteria. Make sure you do
not tip the agar plate as the iodine will leak out. When bacteria produces
, amylase, the starch in the agar will be broken down. Will observe a
clearing around the colonies (amylase positive-clear agar under bacteria)
no visibility through iodine test negative.
●● Amylase Test purpose.
Answer: Differential Test
Used to differentiate gram positive. Amylase extracellular enzyme,
breaks down starch to use sugar to go in cell to be use as energy. Used to
differentiate gram positive
●● Urease Test.
Answer: 1. Obtain agar cultures of bacteria.
2. Obtain 2 urease agar tubes and label them.
3. Using needle inoculate the urease tubes with the stab and streak
technique.
4. Incubate 37 C will be removed after 24-48 hours
Test positive entire tube is pink and yellow if negative
●● Urease Test purpose.
Answer: Differential Test
Used to differentiate gram negatives. Urease is also extracellular enzyme
that breaks down urea to ammonia and carbon dioxide.
Trying to determine which bacteria has the ability to urease enzyme that
catalyze the conversion of urea to ammonium and carbon dioxide, thus
2026 QUESTIONS WITH SOLUTIONS
GRADED A+
●● Catalase Test purpose.
Answer: Differential Test
To determine which bacteria has the catalase to breakdown hydrogen
peroxide into oxygen and water; also used to differentiate gram positive,
however many Gram negatives use catalase as well
●● Amylase Test.
Answer: 1. Obtain agar culture of bacteria
2. Obtain starch hydrolysis plate and on bottom of plate divide into two
sections
3. Label bacteria names on each side
4. Using an inoculation loop, zig zag a line of bacteria on each side.
5. Incubate at the plates upside down at 37 C remove in 24-24 hours.
On next lab
1. Place 1 ml of Lugol's Iodine solution onto the agar plate. Iodine will
cause starch to turn deep brown-black color if it is still present.
2. Look for a clearing in the agar around the bacteria. Make sure you do
not tip the agar plate as the iodine will leak out. When bacteria produces
, amylase, the starch in the agar will be broken down. Will observe a
clearing around the colonies (amylase positive-clear agar under bacteria)
no visibility through iodine test negative.
●● Amylase Test purpose.
Answer: Differential Test
Used to differentiate gram positive. Amylase extracellular enzyme,
breaks down starch to use sugar to go in cell to be use as energy. Used to
differentiate gram positive
●● Urease Test.
Answer: 1. Obtain agar cultures of bacteria.
2. Obtain 2 urease agar tubes and label them.
3. Using needle inoculate the urease tubes with the stab and streak
technique.
4. Incubate 37 C will be removed after 24-48 hours
Test positive entire tube is pink and yellow if negative
●● Urease Test purpose.
Answer: Differential Test
Used to differentiate gram negatives. Urease is also extracellular enzyme
that breaks down urea to ammonia and carbon dioxide.
Trying to determine which bacteria has the ability to urease enzyme that
catalyze the conversion of urea to ammonium and carbon dioxide, thus
