Microbiology final exam Questions and Answers Latest Update 2027

Microbiology final exam Questions and Answers Latest Update
2027

Question 1.
Leeuwenhoek

Correct Answer: Invented the microscope


Question 2.
Pasteur

Correct Answer: - Demonstrated that microorganisms are present in the air
- S-shaped flask
- Showed that microbes are responsible for fermentation
- Pasteurization: high heat for a short time


Question 3.
Koch

Correct Answer: Proved that a bacterium causes anthrax and provided the
experimental stepsKoch's postulates


Question 4.
Koch's postulates

Correct Answer: 1. The microorganism must be found in abundance in all
organisms suffering from the disease, but should not be found in healthy
organisms
2. The microorganism must be isolated from a diseased organism and grown in a
pure culture
3. The cultured microorganism should cause disease when introduced into a
healthy organism
4. The microorganism must be re-isolated from the inoculated, diseased
experimental host and identified as being identical to the original specific
causative agent


Question 5.
Fleming

Correct Answer: Discovered the first antibiotic- penicillin


Question 6.
Brightfield light microscopy

Correct Answer: Dark objects are visible against a bright background

,Question 7.
Darkfield microscopy

Correct Answer: Light objects are visible against a dark background


Question 8.
Transmission electron microscopy

Correct Answer: - Light passes through a ultra-thin section of a specimen, then
an electromagnetic lens, to a screen or film
- Specimen may be stained with heavy metal salts




Question 9.
Scanning electron microscopy

Correct Answer: - An electron gun produces a beam of electrons that scans the
surface of a whole specimen
- Secondary electrons emitted from the specimen produce the image

,Question 10.
Gram stain

Correct Answer: A staining method that distinguishes between two different
kinds of bacterial cell walls.


Question 11.
Gram stain process

Correct Answer: Primary stain: Crystal violet Mordant: Iodine Decolorizing
agent: Alcohol-acetone Counterstain: Safranin


Question 12.
Color after gram stain (gram+ vs. gram-)

Correct Answer: Gram+: Purple Gram-: Red


Question 13.
Gram+ cell wall

Correct Answer: - One plasma membrane
- Cell wall is thicker so there is more peptidoglycan (made up of alternating NAG
& NAM) and teichoic/lipoteichoic acid (hold cell wall together)




Question 14.
Gram- cell wall

Correct Answer: - Two plasma membrane
- Cell wall is thinner so less peptidoglycan and teichoic/lipoteichoic acids
- LPS is the endotoxin in the outer membrane

, Question 15.
Endospore stain

Correct Answer: A differential stain is used to detect the presence and location
of spores in bacterial cells.




Question 16.
Endospore stain- ing process

Correct Answer: Primary stain: Malachite green w/ heat Decolorizing agent:
Water Counterstain: Safranin


Question 17.
Capsule stain

Correct Answer: - Cells stained (positive/basic stain)
- Background stained negative stain)
- Area between stains is the capsule