امتحان microbiology 01

Q1: Write short notes on the following:1. Classification of bacteria according to their oxygen requirement.
2. Tyndalization.
3.Capsules and their methods of identification.
4. Bacterial growth curve.
5. Principle of Gram stain.
6. Principle of ZN stain.

Q2: Write T in front of the true statement(s) and F in front of false statement(s).

1. A bacterium:
a. Is a unicellular microorganism.
b. Divides by binary fission.
c. Contains mitochondria.

2. Eukaryotes:
a. Have no definite nucleus with nuclear membranes.
b. Have a cell wall made of peptidoglycan.
c. are large in size.
d. Have golgi apparatus.
e. fungi and protoza.

3. To test the efficiency of the autoclave we use:
a. Bacillus stercothermophilus.
b. Methylene blue.
c. Bowie dick test.
d. Brown tube No.1.
e. Brown tube No.3.



4. The following statements are true about the autoclave:
a. Steam under pressure is used for sterilization.
b. It is used to sterilize plastic syringes.
c.  A temperature of 121 C for 15 minutes is used for sterilization.
d. it is used to sterilize surgical instruments
e. Air should be removed before sterilization.

5. The following statements are true about the hot air oven:
a. it is used to sterilize glassware.
b. kills bacteria by oxidation.
c. it is used to sterilize oils.
d. can be used to sterilize lab media.
e. it is used to sterilize plastic-ware.

6.Monotrichous flagellum is :
a.Single flagellum from one side.
b.Single flagellum from two side.
c.Group of flagellum from one side.
d.Group of flagellum from two side.
e.Polar flagellum.

7. The main functions of a cell wall are:
a. gives the bacteria its shape.
b. selective permeability.
c. takes the staining reaction of bacteria.
d. protects the bacteria from external environment and osmotic pressure.
e. Protects from phagocytosis.

8. Bacterial spores:
a. is polysaccharide in nature.
b. is protein in nature.
c. found extracellualarly.
d. resist high temperature, dryness and harsh conditions.
e. Albert's stain.

9. The counter-stain in Gram stain is:
a. Crystal violet.
b. Safranin red.
c. Neutral red.
d. used to stain unstained cells after decolorization.
e. not necessary in Gram stain.

10. The decolorizer in Ziehl-Neelsen stain is:
a. 20% alcohol.
b. 3% acid alcohol.
c. 5% acid alcohol.
d. 20% H₂SO₄.
e. 5% alcohol.

11. Ziehl-Neelsen stain is:
a. Differential stain.
b. special stain.
c. simple stain.
d. used for mycobacteria tuberculosis.

12. Counter-stain used in ZN stain:
a. used to clear the background.
b. is methylene blue.
c. is malachite green.
d. picric acid.
e. neutral red.

13. The following is used in to stain volutine granules:
a. simple stain.
b. Albert's stain.
c. Neisser stain.
d. modified ZN stain.
e. negative stain.

14. Sterilization by radiation kills the microbe by:
a. coagulation of protein.
b. denaturation of enzymes.
c. Mutation.
d. inspissation.
e. stopping synthesis of protein.

15. Thermal death point and thermal death time of the autoclave:

a.115^o C for 15 min.
b.100^oC for 30 min.
c.121^oC for 15 min.
d.121^oC for 10 min.
e.65^oC for 30 min.

16. Halogenic disinfectant includes:
a. alcohol.
b. iodine.
c.. glutaraldehyde.
4. chlorine.
5. flourine.

17. psychrophilic bacteria:
a. are found in oceans.
b. are found in hot springs.
c. grows better at 37 C.
d. grows better at 45 C.
e. grows better at 8 C.

18. The bacteria that use organic materials as a source of carbon and light as a source of energy is referred to as:
a. autotrophes.
b. heterotrophs.
c. autophototrophs.
d. auto-chemotrophs.
e. heterophototrophs.

19. halophilic bacteria:
a. are able to grow at high salt concentrations.
b. are isolated from salty foods.
c. could survive in hypotonic solutions.
d. could survive in hypertonc solutions.
e. resist 7% NaCl.

20. Fimbria:
a. are hair-like structures.
b. found on the surface in all bacteria.
c. used by bacteria to help in adhesion.
d. could be seen clearly under a light microscope in unstained smears.
e. helps bacteria in gene transfer.