2013年《微生物学》实验双语测试题

《微生物学》实验双语测试题

《Experiment for microbiology》test

1.Multiple Choice (choose one answer)（每小题2分，共20分）

1.The first microscopes were developed by:

A.Ehrlich

B.Metchnikoff

C.Leewenhoek

D.Lister

2.Light microscopy is dependent on the interaction of light with on object. The ability of light to pass through an object is referred to as:

A.transported light

B.transmitted light

C.reflected light

D.refracted light

3.The resolving power (R) of a microscope is dependent on the wavelength of light (;~) and the numerical aperture (NA) of the lens. The formula for R is:

A.R = 0.5~. xNA

B.R = 0.5;~/NA

C.R = NA/0.5Jr

D.R = Square root of 0.5)./NA

4.The gram stain uses ~ as a mordant to fix the primary stain:

A.iodine

B.alcohol

C.acetone

D.safranin

5.The acid-fast stain is useful in the identification of which of the following organisms:

A.Staphylococcusaureus

B.Mycoplasmamycoides

C.Mycobacteria tuberculosis

D.Moraxellaosloensis

6.Which of the following types of microscopes utilizes electron beams to visualize objects?

A.Nomarski

B.TEM

C.PCM

D.Confocal

7.Sterilization of material with an autoclave utilizes steam to kill microorganisms. The correct procedure for sterilization with an autoclave is:

A.15 min at 121℃at 15 lb/in2

B.15 min at 256℃at 15 lb/in2

C.15 min at 121℃at 1 lb/in2

D.15 rain at 121℃at 30 lb/in2

8.An antibiotic was added to a culture of bacteria to determine its effect. What method of

enumeration would you use to determine the efficacy of the antibiotic?

A.direct count

B.viable count

C.turbidimetric count

D.absorbance

9.The transfer of DNA from one organism to another through the use of a viral vector is referred to as:

A.electroporation

B.conjugation

C.transformation

D.transduction

10. In bacterial cultures, growth can be demonstrated by an increase in:

A.mass

B.cell size

C.cell number

D.cell length

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2．Fill in the Blank（每小题1分，共20分）

1. The structure of the bright-field microscope

Fig 1 Bight-field microscope

1. Ocular lens.

2. Tube.

3. Nosepiece.

4. Objective lens.

5. Stage.

6. Condenser lens.

7. Iris diaphragm.

8. Reflector.

9. Arm. 10. Stage adjustment knob. 11. Condenser adjustment knob. 12. Fine-adjustment knob. 13.Coarse-adjustment knob. 14. Base.

2. IMViC Series include 15.Indole production、16.The Methyl Red Test、17.The Voges-Proskauer Test、18.Citrate Utilization

3. Pasteurization Inoculate Bacillus subtilis and Escherichia coli respectively to nutrient broth, place the tubes to a 63℃water bath for 30 minutes.

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3．Matching（每小题2分，共24分）

Matching I:

l. Primary stain for gram stain a. Negative stain

2. Stains bacterial cell b. Carbohlfuchsin

3. Used to fix stain c. Crystal violet

4. Decolorize d. Malachite green

5. Spore stain e. Safranin

6. Acid-fast stain f. Positive stain

7. Gram- bacteria take up this counterstain g. Alcohol

8. Stains background h. Mordant

1.c

2.f.

3.h

4.g

5.d.

6. b

7.e

8.a

Matching II:

1. Media used to inhibit growth of unwanted organisms a. Enrichment

2. Media where all components are not known b. Selective

3. Media used to contrast organisms on same plate c. Differential

4. Media used to enhance growth d. Complex

1.b

2.d

3.c

4.a

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4．Discussion（每小题12分，共36分）

1. What’s the principle of Gram stain?

A: Gram stain is a popular compound staining technique and differential staining processes are required by the use of crystal violet, Gram’s iodine, 95% ethyl alcohol, and safranin sequentially. It divides bacterial cells into two major groups named gram positive (G ) and gram negative (G-), which makes it an essential tool for classification and differentiation of microorganisms. According to Gram stain, Gram positive bacteria bind crystal violet, couldn’t be decolorized by 95% ethyl alcohol, and appear violet, while Gram negative bacteria are decolorized by 95% ethyl alcohol, bind safranin , and appear red.

Generally, the principle of gram stain are as follows. ①The isoelectric point of gram positive bacteria is lower (pI=2~3) than that of gram negative bacteria (pI=4~5). So it contains much more negative charge and bind to crystal violet tightly. ②The cell wall of gram negative bacteria is composed of outer membrane containing much lipid composition, which is sensitive to ethyl alcohol. When decolorizing with 95% ethyl alcohol, the complex of crystal violet and iodine is extracted from cell wall. ③The cell wall of gram positive bacteria contain less lipid composition that is not sensitive to ethyl alcohol decolorizing. In addition, it contains multiplayer of high percentage of peptidoglycan and teichoic acid with large amount of negative charges. The complex of crystal violet and iodine binds to cell wall tightly and can not be extracted by 95% ethyl alcohol. So it appear purple.

2.What’s the difference of the mycelia and spore between antinomycetes and molds?

A: The primary cell structure of antinomuycetes is similar to bacteria. Antinomycetes have

filament which contain substrate filament and aerial filament and sporebearing filament. Sporebearingfilament differentiate to spore. The shape of sporebearing filament are sphere, ellipse and rod. The morphology and color of aerial filament and spore are important for the classification and characterization of antinomycetes.

Molds are eukaryotic cells and most of them are multicellular and filamented. The filament of molds is often wider than that of antinomycetes. Spores have different shapes and are divided into asexual or sexual ones.

The morphology of mycelia and spore for antinomycetes and molds can be observed by microscope and cultivated on concavity slide or cover slip.

After inoculated on agar culture media and cultured at approximate temperature for some time, microorganisms grow to form colonies from single cell which can been seen by the naked eye. The characteristics of colonies depends on their cell structure and growth behavior which is further used to the identification of microorganisms.

3.How to judge if a pharmaceutical preparation is qualified for microbial contaminations or not? A: According to the pharmacopoeia, drugs for external or oral use need microbial limitation check except for aseptic inspection. That is the number of bacteria and molds and yeast, the pathogenic bacteria such as Escherichia coli, Salmonella species, Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus tetani and living mite.

The microbial standards of drugs are as shown in Table 44.1. In addition, no Salmonella species should be checked in preparations from any animal organs. The number of molds in oral antibiotics should be controlled to be less than 100 CFU/g and bacteria in antifungi orals less than 100 CFU/g too. On the other hand, mildewed and mite contaminated drugs are not qualified. The number of bacteria and molds can be determined by agar plate. Pathogenic bacteria can be confirmed by its morphology biochemical tests while living mite is observed by microscope.

The number of bacteria and molds in the plates is reported in the following way. At first, it is suitable for bacteria counting when there are 30 to 300 colonies in plates while 30 to 100 for molds.

(1) When the number of colonies at one dilution series is among 30 to 300 for bacteria or 30 to 100 for molds, report it.

(2) When the number of colonies at two dilution series is among 30 to 300 for bacteria or 30 to 100 for molds, calculate the ratio as follows:

Where NH and NL are colonies of high and low dilution series respectively, DH、DL are dilution times for two dilution series respectively. When R≤2, the average number of two dilution series is reported and the number of low dilution series is reported for R>2.

(3) When the average number of colonies at three dilution series is among 30 to 300 for bacteria or 30 to 100 for molds, report it based on the two of low dilution series.

(4) When the average number of colonies at all dilution series is not in the range of 30 to 300 for bacteria or 30 to 100 for molds, report colonies number which is most close to the range above.

(5) When the average number of colonies at all dilution series is more than 300 for bacteria or 100 for molds, report colonies number based on the highest dilution series.

(6) When the average number of colonies at all dilution series is less than 30, report colonies

number based on the lowest dilution series.

(7) When the average number of colonies at 1:10 or 1:100 dilution series is not less than colonies of drug or 1:10, media dilution determination should be used.