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تحميل الدليل التدريبي

أسئلة شائعة


 

 

CLINCAL LABORATORY SCIENCES

EXAMINATION- SAMPLE FOR CLS-311

(Prof.Dr. Talat EL-KERSH)

 

 

 

I-Circle the best SINGLE answer

 

1.      Transmission of HIV & HBV is by:

 A.semen and vaginal secretions.         B.blood and blood products.

 C. chlorinated swimming pools.         D.kitchen utensils.      E. Both A & B

 

2.      An Example of phenotypic  variation is :

a.       Induced enzyme formation in presence of substrate or substrate analogues

b.      Variation of motility in relation to temperature (37/27 C)

c.       Protoplasts & spheroplasts

d.      All of above are examples of phenotypic variations.

 

3.      An example of genotypic variation is:

 A. Conversion of smooth (capsule) to rough (no capsulated) colonies

 B. Toxigenic and non- toxigenic  Corynebacterium diphtheriae

 C. Toxigenic and none-toxigenic Streptococcus pyogenes causing scarlet fever

 D. L.forms (irreversible spheroplasts)

 E.All of above are true genotype

 

4.      Formaldehyde & ethylene oxide  kill microorganisms by :

a.       Protein inactivation by alkylation (CH2-bridge formation)

b.      DNA & RNA fragmentation and breakdown

c.       Protein inactivation by direct oxidation

d.      Protein inactivation by water hydration (opening catalytic sites ) then clotting

         & heat coagulation irreversibly.

 

5.      The mechanism by which moist heat autoclaving kills microorganisms is by:

a.       Protein inactivation by alkylation (CH2-bridge formation)

b.      DNA & RNA fragmentation and breakdown

c.       Protein inactivation by direct oxidation

d.      Protein inactivation by water hydration (opening catalytic sites ) then clotting

 & heat coagulation irreversibly.

 

6.      The mechanism by which dried heat sterilization(HAO)kills microorganisms is by:

a.       Protein inactivation by alkylation (CH2-bridge formation)

b.      DNA & RNA fragmentation and breakdown

c.       Protein inactivation by direct oxidation

d.      Protein inactivation by water hydration (opening catalytic sites ) then clotting

 & heat coagulation irreversibly.

 

7.      The mechanism by which ionizing gamma irradiation kills microorganisms is by:

a.       Protein inactivation by alkylation (CH2-bridge formation)

b.      DNA & RNA fragmentation and breakdown

c.       Protein inactivation by direct oxidation

d.      Protein inactivation by water hydration (opening catalytic sites ) then clotting

 & heat coagulation irreversibly.

 

8.      Genes of bacterial multiple antibiotic resistance-determinants are  found on:

  A .The chromosome                 B. The mitochondrial DNA    

  C. Plasmid or transposon        D. an insertion sequence                 

 

9.      Point-mutation(one base substitution), may still show no phenotypic change because:

A. the changed base of the codon still code for the same amino acid

B. because all amino acids have more than one code (61/20)

C. None of the above

 

Answer:1(A&B),2(d),3(E),4(a),5(d),6(c),7(b),8(C),9(A)

 

 

II-Complete the followings:

 

1.      In complement fixation test when RBCs lyses occurred means it is …….test

2.      In Ag-Ab agglutination reaction(as blood grouping) the antigen is……..

3.      In Ag-Ab precipitation reaction (as Elecks –diphtheria) the antigen is…….

4.      The Direct Immune Fluorescence test is always for the detection of ……..

5.      The antigen is attached to its specific antibody by weak ……..

6.      Halophilic organism means it requires ………….to grow

7.      Microaerophilic organism grow in a limited amount of……….by 10% CO2

8.      Example of a thermophil used as QC in autoclaving is ………. stearothermophilus

9.      The first reagent used in spore staining is………………

The first reagent in ZN(AFB )staining is ………….and in capsule staining is…………

 

ANSWE:1(negative),2(particulate insoluble),3(soluble),4(Antigen),5(bonds),6(salts),7(O2)

                8(Bacillus), 9(Hot Malachite green),10(carbol fuchsin), and (Nigrosine,India ink).

 

 

Another sample is the following with answer in RED

 

1.    The rate of reproduction equals the death rate in the stationary phase.

2.    Moist heat is a(n) more effective killing agent than/as dry heat.

3.    An organism that can make ATP only by aerobic respiration is called a(n) obligate aerobe

4.    The temperature required to kill all bacteria in 10 minutes is known as the thermal death point.
Strict anaerobes cannot break down superoxides.

5.    The process of making ATP in which the final electron acceptor is an organic compound is known as fermentation.

6.    Each mole of FADH2 yields sufficient energy for two moles of ATP.

7.    Gamma rays and X-rays are considered ionizing radiation.

8.    A(n) halophile requires a high concentration of salt in order to grow.

9.    Ultraviolet light targets the DNA causing the formation of dimers.

 

 

III-put at LEFT number from Column  B TO  APPROPRIATE  statements in A

 

No

Column        A

 

Column          B

 

Ultra violet-killing effects by

1

Free radicals-nicks DNA& proteins

 

Ionizing radiation(gamma) killing effect

2

Covalent thymine-dimmers-formn.

 

Ethylene oxide & CH2O killing effect by

3

Protein-alkylation(inactivation)

 

Autoclaving-moist heat killing effect by

4

Protein-denaturizing& coagulation

 

Dry heat 160,2hrs killing effect by

5

Mechanical –removal of M.Os

 

Thermo-labile soln.-filtration sterilization

6

Direct protein-oxidation(inactivation)

 

Normal flora of mouth& innate defense

7

Bacteroide fragilis,E.coli,& peristaltic

 

Normal flora-vagina& first line -defense

8

Viridians-Strept.Lactobacilli-enzymes

 

N. flora –GIT & first line -defense

9

S.epidemidis,tears,lyzozyme,mechanic

 

N. flora skin, eye & first line defense

10

Lactobacilli, yeasts, acidic pH

 

None-specific 2nd line defenses

11

B& T cells, memory cells, antibodies

 

Specific acquired immunity

12

WBC, complement,interferon,inflamn.

 

Ag-Ab-agglutination (Blood grouping)

13

Both  antigen & Abs are soluble

 

Ag-Ab-precipitation (Toxin-Antitoxin ppt)

14

The antigen is suspended -particulate

 

Ag-Ab direct immune fluorescent test-DIF

15

Recent infection-1ry immune-respon.

 

IgM-Detection in specimen is a marker for

16

Detect Ag in specimen-UV apple flures.

 

In 2nd immune response ,concentration of

17

IgA is higher & no other Igs

 

Respiratory,mucus,urine, concentration of

18

IgG s higher and almost no Ig M

 

In Ag-Ab complement fixation test(-) give

19

& enzyme-conjugate with Ag or Ab

 

ELISA,measure color formation,substrate

20

RBCs,lysis means complement is free

 

 

 

THE FOLLOWING IS THE ANSWER TO THE ABOVE QUESTION(III)
III-put at LEFT number fromCOLUMN  B TO APPROPRIATE statements in A

 

No

Column        A

 

Column          B

2

Ultra violet-killing effects by

1

Free radicals-nicks DNA& proteins

1

Ionizing radiation(gamma) killing effect

2

Covalent thymine-dimmers-formn.

3

Ethylene oxide & CH2O killing effect by

3

Protein-alkylation(inactivation)

4

Autoclaving-moist heat killing effect by

4

Protein-denaturizing& coagulation

6

Dry heat 160,2hrs killing effect by

5

Mechanical –removal of M.Os

5

Thermo-labile soln.-filtration sterilization

6

Direct protein-oxidation(inactivation)

8

Normal flora of mouth& innate defense

7

Bacteroide fragilis,E.coli,& peristaltic

10

Normal flora-vagina& first line -defense

8

Viridians-Strept.Lactobacilli-enzymes

7

N. flora –GIT & first line -defense

9

S.epidemidis,tears,lyzozyme,mechanic

9

N. flora skin, eye & first line defense

10

Lactobacilli, yeasts, acidic pH

12

None-specific 2nd line defenses

11

B& T cells, memory cells, antibodies

11

Specific acquired immunity

12

WBC, complement,interferon,inflamn.

14

Ag-Ab-agglutination (Blood grouping)

13

Both  antigen & Abs are soluble

13

Ag-Ab-precipitation (Toxin-Antitoxin ppt)

14

The antigen is suspended -particulate

16

Ag-Ab direct immune fluorescent test-DIF

15

Recent infection-1ry immune-respon.

15

IgM-Detection in specimen is a marker for

16

Detect Ag in specimen-UV apple flures.

18

In 2nd immune response ,concentration of

17

IgA is higher & no other Igs

17

Respiratory,mucus,urine, concentration of

18

IgG s higher and almost no Ig M

20

In Ag-Ab complement fixation test(-) give

19

& enzyme-conjugate with Ag or Ab

19

ELISA,measure color formation,substrate

20

RBCs,lysis means complement is free

 

IV-_Short Notes, Choose one of the followings:

1-Dfine plasmids, induced enzymes, restriction enzymes and primers

2-priciples of Plasmid & chromosome DNA isolation and engineering an insulin gene in E.coli

 

 

V-PUT  F for FALSE and T for TRUE statement ABOUT DNA replication

 

1.    The parent strand (3’ to 5’) acts as a template for the Leading strand (5’ to 3’. be replicated in right direction of 5’ to 3’  very fast .

2.    The parent strand 5’ to 3’ has to be replicated in pieces (Okazaki, in 5’ to 3’)  slowly  to form the Lagging strand .as DNA polymerase CAN NOT work 3’to 5’ direction.

3.    In either case replication starts with RNA primer(primase)

4.    Later on primers are  cut off &replaced  by DNA using a special DNA polymerase.

5.    Only okazaki pieces that are need to be joined by DNA –ligase 

 

ANSWER:1(T) ,2 (T),3(F),4(T),5(T)

 

 

 

 
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