SMSA BigBrother General Microbiology & Immunology Qs Book

MICROBIOLOGY

Questions For 1st year

Bacterial structure 1

Previous exams & Formative:

1- Bacterial chromosome is composed of:

a. Double stranded DNA

b. Double stranded RNA

c. Single stranded DNA

d. Single stranded RNA

2- When flagella are distributed all around a bacterial cell, the arrangement is called:

a. Polar

b. Peritrichous

c. Encapsulated

d. Monotrichous

3- Differences between eukaryotic and prokaryotic cells include all of the followings Except:

a. Eukaryotic cells have mitochondria

b. Prokaryotic cells have more complex cell walls

c. Eukaryotic cells have cilia and flagella with complex structure

d. The prokaryotic cells divide by binary fission.

4- The envelope surrounding the nucleocapsid of some viruses is made up of which of the following structures:

a. Lipoproteins

b. Peptidoglycan

c. Lipopolysaccharides

d. Chitin

5- A small circular double stranded DNA that is capable of autonomous replication is called:

a. Bacterial chromosome.

b. Plasmid

c. Phage

d. Transposon

6- Genetic material of bacterial cell is composed of:

a. Single linear bacterial chromosome only

b. Single circular bacterial chromosome only

c. Single circular bacterial chromosome and extra-chromosomal elements.

d. Plasmids and phages only

7- Causes of marked resistance of spores include the following Except:

a. Thick spore cortex and tough coat.

b. Their dehydrated state.

c. Their very high metabolic and enzymatic activity.

d. The bacterial spores contain large amount of dipicolinic acid

8- The significance of the plasma membrane includes all the following Except:

a. It selectively allows some molecules to pass into the organism

b. Supplies the cell with energy

c. Provides enzymes and lipid carriers for cell wall synthesis.

d. Responsible for the staining affinity of the bacterial cell

9- All the following represent bacterial cell wall functions Except:

a. It is a rigid structure that maintains shape of bacteria.

b. Excretion of pathogenicity proteins and some exotoxins

c. Protects the cytoplasmic membrane from bursting in hypotonic solutions

d. Determine the reaction to Gram stain

10- Functions of flagella include all the following Except:

a. Organ of locomotion and chemotaxis

b. Antigenic function used for typing and diagnosis.

c. Responsible for adhesion and attachment to mucosa

d. Penetrating through viscid mucus secretions and epithelial barriers and spreading throughout body fluids and tissues

11- The genetic material in virus is:

a. DNA only

b. RNA only

c. DNA or RNA

d. DNA and RNA

12- A main component of the cell wall of gram -ve bacteria that is concerned with pathogenesis is:

a. Enterotoxin.

b. Teichoic acid

c. Endotoxin

d. Peptidoglycan

e. Pili

13- What is responsible for the endotoxin activity of LPS:

a. Core polysaccharide

b. O antigen

c. Lipid A

d. H antigen

e. K antigen

14- Which of the following structures is involved in bacterial attachment cell surfaces:

a. Flagella

b. Pili

c. Mesosomes

d. Peptidoglycan

e. Teichoic acid

15- Peptidoglycan layer is present in large quantity in:

a. Gram-positive bacteria

b. Gram-negative bacteria

c. Fungi

d. Algae

16- Which of the following is NOT the basic shape of the bacteria:

a. Rod shape

b. Square shape

c. Comma shape

d. Spiral shape

17- Differential staining of bacteria on Gram staining is due to:

a. Difference in the cell wall layer components of Gram positive and Gram negative bacteria

b. Difference in the cell structure of Gram positive and Gram negative bacteria

c. Difference in the mode of nutrition of Gram positive and Gram negative bacteria

d. None of the above

18- The ability of bacteria to change their morphological form frequently is:

a. Lysogeny

b. Pleomorphism

c. Alter morphism

d. None of these

19- bacterial flagella is made up of:

a. Microtubules

b. Tubulin

c. Flagellin

d. Spinin

20- Surface appendage of bacteria meant for cell-cell attachment during conjugation:

a. Pilli

b. Bacterial structure

c. Flagella

d. Spinae

e. Cilia

21- The region where bacterial genome resides is termed as:

a. Nucleus

b. Cytoplasm

c. Nucleoid

d. Ribosome

22- The organ of locomotion of bacteria is:

a. Capsule

b. Flagella

c. Slime

d. Fimbriae

23- H antigen is a:

a. Somatic antigen

b. Flagellar antigen

c. Capsular antigen

d. Virulent antigen

24- Plasmid is a:

a. Extrachromosomal genetic element in the bacterial chromosome

b. Segment of DNA carrying codons specifying for a particular polypeptide

c. Triple nucleotide group, coding one specific amino a

d. Segment of rna

25- Bacterial cell wall is made up of:

a. Chitin

b. Cellulose

c. Dextran

d. Peptidoglycan

26- K antigen is a:

a. Somatic antigen

b. Flagellar antigen

c. Capsular antigen

d. Virulent antigen

27- Gram positive microorganisms have:

a. Violet color

b. Pink-red color

c. Green color

d. Black color

28- An outer covering in some bacteria that protects them from phagocytosis by host cells is:

a. Capsule

b. Cell wall

c. Flagellum

29- A nontoxic virulence factor that promotes survival of a pathogen by protecting it from phagocytosis is :

a. Pili

b. Capsule

c. An enzyme

d. Mucous membrane

30- Which of the following is not true related to endotoxins:

a. Endotoxins are secreted from cells

b. Cause of endotoxic shock

c. Produced by gram negative microorganisms

d. Cause fever

Bacterial growth 2

Previous exams & Formative:

1- Bacterial chromosome is composed of:

a. Double stranded DNA

b. Single stranded DNA

c. Double stranded RNA

d. Single stranded RNA

2- All genetic material of bacteria is composed of;

a. Single linear bacterial chromosome only

b. Single circular bacterial chromosome only

c. Single circular bacterial chromosome and extra-chromosomal elements

d. Plasmid and phages only

3- Bacteria which need oxygen for growth are called:

a. Thermophilic bacteria

b. Anaerobic bacteria

c. Facultative anaerobic bacteria

d. Mycobacteria

4- PH required for the growth of bacteria is:

a. 6.8-7.2

b. 5.6-8.2

c. 3.0-6.0

d. 8.0-14.0

5- The orderly increase in the quantity of all cellular components is known as:

a. Reproduction

b. Growth

c. Binary fission

d. None of the above

6- Optimum growth temperature is greater than 45C is:

a. Mesophiles

b. Thermophiles

c. Psychrophiles

d. None of these

7- The organism that can grow both in presence and absence of oxygen:

a. Aerobes

b. Anaerobes

c. Facultative anaerobes

d. Strict aerobes

8- The organism that can grow best in a low concentration of oxygen:

a. Aerophilic

b. Microaerophilic

c. Aerobic

d. Anaerobic

9- Tubercular bacilli grow best in:

a. Absence of oxygen

b. Presence of Co2

c. Presence of O2

d. None of these

10- Bacteria are more sensitive to antibiotic at which phase of growth curve:

a. Decline of phase

b. Stationary phase

c. Lag phase

d. Log phase

11- An organism that lack superoxide dismutase and catalase to remove toxic superoxide are:

a. Obligate anaerobes

b. Obligate aerobes

c. Facultative anaerobes

d. Microaerophilic

12- In bacterial growth curve, maximum growth occurs during:

a. Decline phase

b. Stationary phase

c. Lag phase

d. Log phase

13- During the bacterial growth, death rate exceeds the multiplication rate in:

a. The lag phase

b. The log phase

c. The stationary phase

d. The decline phase

Extra:

1- The group of bacteria which depends on organic sources in nature for their energy requirement are said to be:

a. Phototrophs

b. Autotrophs

c. Chemotrophs

d. Heterophils

2- The lag phase of bacterial growth curve correlates in vivo with which of the following:

a. Symptoms and signs of disease

b. Incubation period

c. Invasive period

d. Convalescence

3- Only one of the following is true about the bacterial growth curve:

a. Can be obtained by growing bacteria on solid media.

b. Decline phase is absent in some bacteria.

c. Lag phase is equal in all bacteria.

d. Logarithmic phase correlate with convalescent phase of disease.

e. Stationary phase accompanied by bacterial death.

4- The rate of the bacterial growth during the stationary phase is:

a. Zero

b. Constant

c. Increasing

d. Decreasing

Bacteriophages 3

Previous exams & Formative:

1- The genome of bacteriophage can be:

a. DNA only

b. Both DNA and RNA

c. Either DNA or RNA

d. RNA only

2- Bacteriophage responsible for lysogenic cycle is called:

a. Temperate phage

b. Virulent phage

c. Lytic phage

d. None of the above

3- Which of the following is true about the lysogenic phage cycle?

a. It is caused by lytic phage.

b. The phage does not insert itself in the bacterial chromosome.

c. Specialized transduction occurs as an error of the temperate phage from the bacterial chromosome.

d. Specialized transduction occurs as an error in assembly.

4- About the lytic cycle, select one:

a. The phage is said to be virulent.

b. The phage is known as temperate phage.

c. The phage DNA is inserted into the bacterial chromosome.

d. Ends by bacterial cell replication.

5- The virulence factor that acquired by lysogenic conversion is encoded by the DNA of:

a. Conjugative plasmid

b. Lytic phage

c. Temperate phage

d. Integron

6- The error that occurs during the assembly phase of bacterial phage replication and that leads to incorporation of part of bacterial DNA into the phage particle is termed as:

a. Transformation

b. Generalized transduction.

c. Transposition

d. Specialized transduction

e. Conjugation

1-c 2-a 3-c 4-a 5-c 6-b

Extra:

1- Lysogenized bacterial cell is the cell containing:

a. Inclusion bodies

b. Bacteriocins

c. Endopigments

d. Prophage

2- Host specificity of the phage is usually determined by:

a. Type of enzyme that the phage has

b. Type of nucleic acid in the head

c. Shape of the capsid

d. The tail

e. Contractile sheath

3- The generalized transduction is a process of gene transfer when:

a. Free DNA is transferred to bacteria.

b. Transfer of any segment of donor DNA randomly by bacteriophage.

c. A specific bacteriophage transduces only a particular gene.

d. Transfer by sex factor.

e. Transfer by temperate phage

4- Bacteriophages are:

a. Bacteria attack viruses

b. Viruses attack bacteria

c. Free living viruses

d. All of the above

5- Bacteriophage undergoes replication by:

a. Binary fission and fragmentation

b. Lytic and lysogenic cycles

c. Both

d. None

6- The order of lytic cycle is:

a. Adsorption-Injection of genetic material-maturation-biosynthesis-lysis and release.

b. Adsorption-Injection of genetic material- prophage.

c. Adsorption-Injection of genetic material-biosynthesis- maturation- lysis and release.

d. Adsorption- Injection of genetic material- lysis

7- The viral genome integrated to the bacterial genome is called:

a. Plasmid

b. Prophage

c. Virion

d. Capsid

8- Lysogenic strains are also called:

a. Temperate phages

b. Avirulent phages

c. Both a & b

d. None of the above

Previous exams & Formative:

1. A small circular double stranded DNA that is capable of autonomous replication is called:

a. Bacterial chromosome

b. Transpose

c. Phage

d. Pathogenicity island

e. Plasmid

2. The error that occurs during the assembly phase of bacterial phage replication and that leads to incorporation of part of bacterial DNA into phage particle is termed:

a. Transformation

b. Generalized transduction

c. Transposition

d. Specialized transduction

e. Conjugation

3. Uptake by recipient cell of soluble DNA released from a donor cell is defined as:

a. Conjugation

b. Recombination

c. Competence

d. Transformation

e. Transduction

4. All of the following are methods of gene transfer from one bacterial cell to another except

a. Conjugation

b. Mutation

c. Transformation

d. Generalized transduction

5. All the following is true about plasmids except:

a. They are circular molecules

b. They are double stranded

c. They are capable of autonomous replication

d. They cannot move from one bacterial strain to another

6. Which of the following is true about lysogenic phage cycle:

a. It is caused by lytic phage

b. The phage doesn't insert itself in the bacterial chromosome

c. Specialized transduction occurs as an error in excision of the temperate phage from the bacterial chromosome

d. Specialized transduction occur as an error in assembly

7. All genetic material of bacteria is composed of:

a. Single linear bacterial chromosome only

b. Single circular bacterial chromosome only

c. Single circular bacterial chromosome and extra-chromosomal elements

d. Plasmids and phages only

8. A process that allows defective viruses to replicate and spread is called:

a. Recombination

b. Reassortment

c. Complementation

d. Interference

9. Bacterial chromosome is composed of:

a. Double stranded DNA

b. Double stranded RNA

c. Single stranded DNA

d. Single stranded RNA

10. Which of the following is not true regarding criteria of good cloning vector:

a. It should be small in size

b. It should be capable of autonomous replication

c. It should be well characterized regarding restriction endonuclease cleavage site

d. It should have a wide host range

11. Direct transfer of a plasmid between two bacteria is defined as

a. Conjugation

b. Recombination

c. Competence

d. Transformation

e. Transduction

12. Mutations that can multiply under some conditions but not under other conditions are:

a. Plaque-size mutants

b. Conditional-lethal mutants

c. Host-range mutants

d. Drug-resistant mutant

1. Plasmid is a:

a. Plasma protein

b. Cytoplasmic granules

c. Genetic factor

d. Part of plasma membrane

e. Serum factor

2. The transfer of specific parts of bacterial DNA to another bacteria cell can be mediated by:

a. Transformation

b. Specialized transduction

c. Conjugation

d. Generalized transduction

e. Recombination

3. Plasmids that can mediate gene transfer by conjugation are Known as:

a. F factor

b. Conjugative transposon

c. R factor

d. Cosmid

e. Col factor

4. Which one of the following processes involves a sex pilus?

a. Conjugation resulting in transfer of an R factor

b. Transposition of a mobile genetic element

c. Integration of a temperate bacteriophage

d. Transduction of a chromosomal gene

e. Recombination of a homologous genetic element

5. A form of genetic transfer in which donor DNA is introduced in the recipient by a bacterial virus:

a. Conjugation

b. Transduction

c. Vertical gene transfer

d. Transcription

e. Transformation

6. Plasmid could be transmitted to other bacteria in:

a. Transformation

b. Generalized transduction

c. Conjugation

d. Specialized transduction

e. Fusion

7. The mode of transfer in which naked DNA is directly taken by the recipient cell is known as:

a. Transformation

b. Cell transmission

c. Transduction

d. Cell fusion

8. Drug resistance in bacteria is mainly determined by:

a. F factor

b. R factor

c. Col factor

d. Lysogenic factor

9. Genetic information essential for bacterial life is a function of:

a. Plasmid

b. Chromosome

c. Mesosomes

d. Ribosome

10. Plasmid governs the following functions in bacteria EXCEPT:

a. Drug resistance

b. Bacteriocin production

c. Virulence

d. Production of endotoxin

e. Production of capsule

11. Heritable changes in genome are called:

a. Conjugation

b. Mutation

c. Transduction

d. Replication

12. Transformation is a process of gene transfer in bacteria. It involves:

a. Taking up of DNA from the environment

b. Transfer of DNA from mother cell to its progeny

c. Transfer of genes between bacteria during cell contact

d. Transfer of genes from bacterial viruses to bacterial cell

e. Transfer of genes from plasmid to chromosome

13. The transfer of a portion of the DNA from one bacterium to another by bacteriophage is known as:

a. Transcription

b. Complementation

c. Transduction

d. Conjugation

14. The generalized transduction is a process of gene transfer when:

a. Free DNA is transferred to bacteria

b. Transfer any segment of donor DNA at random by bacteriophage

c. A specific bacteriophage transduces only a particular gene

d. Transfer by sex factor

e. Transfer by temperate phage

15. All the following is true about plasmids except:

a. They are circular molecules

b. They are double stranded

c. They are capable of autonomous replication

d. They cannot move from one bacterial strain to another

16. Extra-chromosomal double stranded DNA that is capable of autonomous replication is:

a. Bacterial chromosome

b. Plasmid

c. Bacteriophage

d. None of the above

17. If a base replaces by another base pair sequence the mutation the resulting replacement is known as

a. Alternation

b. Substitution

c. Missense

d. Nonsense

18. When one or more base pair are deleted or added in the sequence shifts the reading frame on the ribosome called

a. Substitution mutation

b. Missense mutation

c. Nonsense mutation

d. Frameshift mutation

19. Transfer of genes between cells that are in physical contact with one another is known as transformation.

a. True

b. False

Previous exams & Formative:

1- Selective toxicity:

a. Is the ability of an antimicrobial agent to protect a pathogen without harming the host.

b. Is the ability of an antimicrobial agent to harm a pathogen with harming the host.

c. Is the ability of an antimicrobial agent to harm a pathogen without harming the host.

d. Is the ability of an antimicrobial agent to harm the pathogen and the host.

2- Which of the following is the Complication of antimicrobial chemotherapy

a. Hypersensitivity

b. Emergence of resistant mutants.

c. Toxicity

d. All of the above

3- All of the following are Mechanisms of action of antimicrobial agents except

a. Inhibition of bacterial protein synthesis

b. Inhibition of bacterial nucleic acid synthesis

c. Reduction of the intracellular concentration of the antibiotic

d. Interference with the cell membrane function

4- PABA (para-aminobenzoic acid) is important in bacteria for

a. Synthesis of folic acid

b. Molecularly similar to Cephalosporins

c. A substrate used in the production of sulphonamides

d. Synthesis of bacterial cell wall

5- The most selective antibacterial agents are those that interfere with bacterial cell wall synthesis. This is because

a. Eukaryotic cells inactivate the drugs before they can do any damage

b. Eukaryotic cells do not take up the drugs

c. Bacterial cell walls have a unique structure not found in eukaryotic host cells

d. Bacterial cell wall synthesis is easily inhibited whereas eukaryotic cell wall synthesis is more resistant to the actions of the drugs

6- The mechanism of action of Aminoglycoside antibiotics is to:

a. Inhibit cell wall synthesis

b. Bind to bacterial DNA polymerase

c. Inhibit folic acid biosynthesis

d. Bind to the 30s ribosomal subunit

7- Chloramphenicol inhibits the growth of the microbes by carrying out which of the following actions?

a. Inhibition of cell wall synthesis

b. Damage to cytoplasmic membrane

c. Inhibition of nucleic acid synthesis

d. Inhibition of specific enzyme systems

e. Inhibition of protein synthesis

8- The antimicrobial action is through inhibition of cell wall synthesis for all of the following drugs EXCEPT:

a. Cephalosporins

b. Cycloserine

c. Penicillins

d. Vancomycin

e. Aminoglycosides

9- Resistance to Penicillin and other B lactams is due to

a. Modification of target pbps

b. Impaired penetration of drug to target pbps

c. Presence of an efflux pump

d. Inactivation of antibiotics by B lactamase

e. All of the above

10- Which one of the following antibiotics inhibits dihydrofolate reductase?

a. Penicillin

b. Chloramphenicol

c. Trimethoprim

d. Tetracycline

e. Sulfonamides

11- All of the followings are considered mechanism of action of antibiotic except:

a. Inhibition of bacterial cell wall synthesis

b. Interference with the cell membrane function

c. Modification of the target site for the antibiotic

d. Inhibition of bacterial nucleic acid synthesis

12- B-lactam antibiotics: e.g., penicillins, cephalosporins, carbapenems and monobactams:

a. Inhibit the last steps of peptidoglycan synthesis

b. Inhibit early steps of peptidoglycan synthesis

c. Inhibit the Intermediate steps of peptidoglycan synthesis

d. All of above

13- B-lactam antibiotics: e.g., penicillins and cephalosporins act by:

a. Interference with the cell membrane function

b. Inhibition of bacterial cell wall synthesis

c. Inhibition of bacterial protein synthesis

d. Inhibition of bacterial nucleic acid synthesis

14- Cell wall biosynthesis is inhibited by antibiotics by inhibiting the biosynthesis of which of the following?

a. Lipopolysaccharide

b. Cellulose

c. Peptidoglycan

d. Proteins

e. Teichoic acid

15- Which of the following inhibits protein synthesis by combining with the 50S subunit ribosome?

a. Streptomycin

b. Tetracycline

c. Chloramphenicol

d. Penicillin

e. Vancomycin

16- Polymyxins inhibit the growth of the microbes by carrying out which of the following actions?

a. Inhibition of cell-wall synthesis

b. Damage to cytoplasmic membrane

c. Inhibition of nucleic acid

d. Inhibition of specific enzyme systems

e. Inhibition of protein synthesis

17- All of the following are B-Lactam antibiotics except

a. Vancomycin

b. Benzylpenicillin

c. Cephalosporin

d. Monobactam

e. Carbapenems

18- A hospitalized patient develops dysuria and suprapubic pain and is treated with a quinolone. What is the mechanism of action of this antibiotic?

a. It inhibits dihydrofolate reductase.

b. It inhibits DNA- dependent RNA polymerase.

c. It inhibits protein synthesis by binding to the 30s ribosomal subunit.

d. It inhibits protein synthesis by binding to the 50s ribosomal subunit.

e. It inhibits DNA gyrase.

19- Inhibitors of DNA synthesis include which of the followings?

a. Penicillins

b. Polymyxins

c. Quinolones

d. Chloramphenicol

e. Cephalosporins

20- Certain enzymes catalyze the cross-linking of peptidoglycan, a unique constituent of bacterial cell walls. Which of the following may be a factor in antibiotic resistance, the target of which is cell-wall synthesis?

a. RNA polymerase

b. Reverse transcriptase

c. Penicillin-binding proteins (pbps)

d. DNA gyrase

e. Restriction endonuclease

Bacterial Pathogenesis 7

Previous exams & Formative:

1- All the following are characters of carriers Except:

a. They are not confined to bed

b. They carry the pathogenic organism in the inter-epidemic periods

c. They communicate with public without being noticed

d. They have symptoms of disease

2- Endotoxin produced by gram negative bacteria is present in

a. Peptidoglycan

b. Lipopolysaccharide (Lipid A)

c. Teichoic acid

d. Inner membrane

3- Mediate adherence to epithelial surfaces:

a. Capsule

b. Ordinary pili

c. Glycocalyx

d. Sex pili

e. Cell wall

4- Which part of a microbial cells causes an endotoxin?

a. Cell wall

b. Cell membrane

c. Pili

d. Flagella

5- Which of the following is not true related to endotoxins?

a. Endotoxins are secreted from cells

b. Cause of endotoxins shock

c. Produced by gram negative microorganisms

d. Can cause fever

6- Which of the following is the most important structure related to microbial attachment to cells?

a. Flagellum

b. Plasmid

c. Peptidoglycan

d. Glycocalyx

7- What is defined as the number of microbes required to produce a disease?

a. Infectious Dose

b. Pathogen

c. Pathogenesis

d. Disease

8- Hyaluronidase causes damage to which of the following?

a. Connective tissue

b. Nails

c. Collagen

d. All of the above

9- Which of the following is considered an adherence factor?

a. Fimbriae

b. Capsule

c. Slime layer

d. Both a & c

6- d 7-a 8-a 9- d

Extra:

1- Which of the following applies to hyaluronidase?

a. It acts as a spreading factor

b. It promotes blood clotting.

c. It is an example of an adhesin

d. It is produced by immune cells to target pathogens.

2- The most important virulence factors are:

a. Adhesions

b. Invasiveness

c. Toxigenicity

d. Enzymes

e. All of the above

3- Which is the following enzyme acts as a spreading factor?

a. Hyaluronidase

b. Coagulase

c. Catalase

d. DNase

4- The bacterial pili mainly contain:

a. Carbohydrates

b. Lipids

c. Proteins (pilins)

5- Toxoid is:

a. Toxin lost its toxicity but still antigenic

b. Toxin lost its toxicity and antigenicity

c. Toxin lost its antigenicity but not toxicity

d. Toxin lethal in very minimal dose

e. Toxin lethal to bacteria

6- The exotoxins are usually:

a. Thermolabile

b. Thermostable

c. Not affected by formalin

d. Neurotoxins

e. Enterotoxins

7- The ability of a pathogen to spread in the host tissues after establishing the infection is known as

a. Adhesion

b. Invasiveness

c. Toxigenicity

d. None of these

8- A toxic material within the bacterial cell, non -diffusible usually lipopolysaccharideprotein complex, heat and formalin stable and poorly antigenic. This material is:

a. Endopigment

b. Endotoxin

c. Endogenous pyrogen

d. Exotoxin

e. B & C are correct

9- All of the following are characters of endotoxin EXCEPT:

a. Heat stable

b. Polysaccharide lipid complex

c. Action is often enzymatic

d. Produced by gram negative bacteria

e. Poorly immunogenic

10- Coagulase enzyme is able to accelerate the formation of fibrin cl from its precursor fibrinogen. It is considered an important virulent factor for bacteria. Which bacterial species can produce it?

a. Streptococcus pyogenes

b. Staphylococcus aureus

c. Staphylococcus epidermidis

d. Staphylococcus saprophyticus

e. Streptococcus agalactiae

11- Exotoxin have all of the following characters EXCEPT:

a. Enzymatic action

b. Specific tissue affinity

c. Active in minute dose

d. Polysaccharide lipid in nature

e. Strong immunogen

12- The role of bacterial capsules as virulence factors is usually related to their ability to interfere with:

a. Antibody binding

b. B lymphocyte activation

c. Antibacterial penetration of bacterial cells

d. Phagocytosis

e. The release of interferon-gamma and other macrophage activating cytokines

13- Carriers constitute an important source of infection. The following is CORRECT regarding carriers:

a. They carry pathogenic organisms but have mild symptoms

b. They carry pathogenic organisms only for short periods

c. They are apparently healthy

d. They cannot transmit pathogenic organisms to others

e. They transmit infections to others only during epidemics

14- A quantitative measure for pathogenicity is known as:

a. True pathogenicity

b. Virulence

c. Transmissibility

d. Toxicity

e. Reproducibility

15- All the following is correct regarding opportunistic pathogens EXCEPT:

a. Frequently cause infection in healthy subjects

b. Cause infection in immunocompromised patients

c. Are usually members of normal flora

d. Known as potential pathogens

e. Are not true pathogens

16- Virulence of an organism is a quantitative measure for pathogenicity. All the following is correct with regard to virulence EXCEPT:

a. Measured by the number of organisms required to cause disease

b. Expression could be regulated by environmental factors

c. Cannot be transmitted between bacteria

d. Genes could be plasmid or phage encoded

e. Genes are usually aggregated in pathogenicity associated islands

17- Invasiveness of bacteria could be facilitated by:

a. Coagulase enzyme

b. Collagenase enzyme

c. Catalase enzyme

d. Urease enzyme

e. Exotoxin with enzymatic activity

18- Which one of the following microbial structures has anti-phagocytic action? Select one:

a. Spores

b. Capsule

c. Cell wall

d. Flagella

19- Pathogens that can cause serious infections in immunocompromised patients are called Select one:

a. Infectious pathogens

b. Lethal pathogens

c. Virulent pathogens

d. Opportunistic pathogens

20- Which of the following choices lists the steps of pathogenesis in the correct order?

a. Invasion, infection, adhesion, exposure

b. Adhesion, exposure, infection, invasion

c. Exposure, adhesion, invasion, infection

d. Disease, infection, exposure, invasion

21- Which of the following would be a virulence factor of a pathogen?

a. A surface protein allowing the pathogen to bind to host cells

b. A secondary host the pathogen can infect

c. A surface protein the host immune system recognizes

d. The ability to form a provirus

22- Which of the following applies to hyaluronidase?

a. It acts as a spreading factor.

b. It promotes blood clotting.

c. It is an example of an adhesin.

d. It is produced by immune cells to target pathogens.

23- Phospholipases are enzymes that do which of the following?

a. Degrade antibodies

b. Promote pathogen spread through connective tissue.

c. Degrade nucleic acid to promote spread of pathogen

d. Degrade cell membranes to allow pathogens to escape phagosomes

21- a 22-a 23- d

Viral structure

Previous exams & Formative:

1- Which of the following statements about viruses are not true:

a. Viruses contain DNA or RNA

b. The virus' nucleic acid is surrounded by a protein coat

c. Viruses multiply inside living cells using viral mRNA, viral tRNA, and viral ribosomes

d. For DNA viruses (except pox viruses) assembly occurs in nucleus. In RNA viruses and pox viruses assembly occurs in the cytoplasm

e. Early viral proteins are enzymes required for replication of the viral genome

2- Naked viruses are:

a. Enveloped

b. Non enveloped

c. Prions

d. Viruses are genetically deficient and so incapable of producing infectious daughter virion

e. Infective agents with protein free, with low molecular weight RNA

3- The capsid is composed of:

a. Peplomers

b. Nucleic acid

c. Capsomers

d. Envelope

e. Glucose

4- Prions are:

a. Viruses are genetically deficient and so incapable of producing infectious daughter virion

b. Infective agents with protein free, with low molecular weight rna

c. Protein infections particles lack detectable nucleic acid

d. Extrachromosomal genetic elements

e. Defective viruses

5- Enveloped viruses obtain their envelopes by:

a. Modifying vesicles that may be used in the exporting of cellular proteins

b. Breaking down the membrane of the cell they infect and incorporating the lipid into the capsids

c. Budding through the cells or nuclear membrane as the leave the infected cell

d. Encoding an enzyme which synthesizes the necessary lipids for the envelope

e. All of the above

6- The envelope surrounding the nucleocapsid of some viruses is made up of which of the following structures:

a. Lipoproteins

b. Lipopolysaccharides

c. Peptidoglycan

d. Chitin

7- The genetic material in virus is:

a. DNA only

b. RNA only

c. DNA or RNA

d. DNA and RNA

8- Virus multiplies in:

a. Living tissues

b. Culture media

c. Dead tissue

d. Soil

9- Infectious particles that are formed of proteins only is called:

a. Prions

b. Virion

c. Phage

d. Viroid

10- Viruses that consist of only a nucleocapsid are considered:

a. Naked viruses

b. Incomplete viruses

c. Simple viruses

d. Viroids

11- How do enveloped viruses exit their host?

a. Rupturing the virus

b. Bursting the host cell

c. Budding or exocytosis

d. None of these are correct

e. Endocytosis

12- Which of the following statements is correct about capsomers:

a. It is an individual unit of the capsid

b. It is a viral protein for replication

c. It is a unit of nucleic acid in viruses

d. All of the above

13- Which of the following viruses have a complex symmetry:

a. Alphavirus

b. Morbillivirus

c. Poxvirus

d. Parvovirus

14- A structural component that is found in all viruses is:

a. The envelope

b. DNA

c. Capsid

d. Tail fibers

15- Which of the following is true about envelope:

a. Derived from host cell membrane

b. Lipoprotein in nature

c. Has projecting spikes on the surface

d. All of the above

16- Capsid in nature is a:

a. Protein

b. Lipid

c. Polysaccharide

d. Lipoprotein

17- The following properties about viruses are true except:

a. Very small in size

b. Treated by antibiotics

c. Can pass through bacterial filters

d. Most of them can be seen only by electron microscopy

18- Defective viruses are:

a. Virus can replicate only if the cells are co infected with helper virus

b. Infective agents with protein free, with low molecular weight RNA

c. Protein infections particles, lack detectable nucleic acid

d. Extrachromosomal genetic elements

19- Contain host cell DNA Instead of viral DNA within the capsid virus:

a. Defective viruses

b. Pseudovirions

c. Virion

d. Prions

Extra:

1- Which of the following is the single stranded DNA virus:

a. Pox virus

b. Parvo virus

c. Herpes virus

d. Mumps virus

2- Which of the following statements are true about the viruses:

a. Free-living

b. Obligate parasites

c. Both (a) and (b)

d. None of the above

3- Which of the following are the main functions of the capsid:

a. Determines the antigenic specificity of the virus

b. Protects genetic material from nuclease attack

c. Both A and B

d. None of these

4- The outer viral proteins also act as:

a. Antibody

b. Receptor

c. Antigen

d. Coat

5- The component(s) of a virus that is/ are extended from the envelope for attachment is/are the:

a. Capsomeres

b. Spikes

c. Nucleic acid

d. Viral whiskers

Virus Classification 9

Previous exams & Formative:

1- The viruses which known as Pneumotropic viruses are classified according to:

a. Baltimore classification

b. Tissue tropism

c. Type and character of viral genome

d. Morphology of virion

2- Nidovirales were named according to level..........of virus taxonomy of International Committee on Taxonomy of Viruses:

a. Orders

b. Families

c. Genus

d. Species

3- The virus classification which depends on their mode of replication and type of viral genome is:

a. International Committee on Taxonomy of Viruses

b. Baltimore classification

c. Tissue tropism

d. None of the above

4- AII DNA viruses are dsDNA except:

a. Parvoviruses.

b. Adenoviruses.

c. Herpesviruses.

d. Hepadnaviruses

5- All RNA viruses are ssRNA except:

a. Paramyxoviruses

b. Togaviruses

c. Reoviruses

d. Picornaviruses

6- According to the universal system of virus taxonomy, which of the following is considered family?

a. Herpesviridae

b. Herpesvirinae

c. Herpesvirales

d. Herpesvirus

EXTRA

1- Which of the following is a type VI virus according to the Baltimore classification?

a. Poxvirus

b. Parvovirus

c. Reovirus

d. Retrovirus

2- All of following families contain dsDNA except:

a. Polymaviridae

b. Parvoviridae

c. Poxviridae

d. Papillomaviridae

3- According to the universal system of virus taxonomy, one of the following is considered subfamily:

a. Poxviridae

b. Poxvirales

c. Capripoxvirus

d. Chordopoxvirinae.

4- What is the most important factor for virus classification?

a. Chemistry of the DNA and RNA

b. The geometry of the virus

c. The disease a virus causes

d. How many proteins the virus has

e. How many enzymes the virus has

5- The suffix "viridae" is used with which of the following:

a. Genus

b. Order

c. Family

d. Species

e. Subfamily

6- The suffix "virinae" is used with which of the following?

a. Species

b. Order

c. Family

d. Subfamily

e. Genus

7- The study of classification is called:

a. Systematics

b. Taxonomy

c. Analytics

d. Phylogeny

8- Which of the following groups affect the respiratory system?

a. Dermotropic

b. Viscerotropic

c. Neurotropic

d. Pneumotropic

9- In the Viscerotropic group the tissue affected:

a. Subcutaneous tissues

b. Gastrointestinal organs

c. Cardiovascular system

d. Central nervous system

10- According to Baltimore classification, viruses having ss-DNA as their genome can be put in which group number?

a. Group I

b. Group II

c. Group III

d. Group IV

11- All of the following are respiratory virus except:

a. Adenovirus

b. Orthovirus

c. Rotavirus

d. Rhinovirus

12- The Subfamily end with suffix:

a. Virinae

b. Viridae

c. Virus

d. Virion

13- Tissue tropism, host range, and mode of transmission are considered to be:

a. Properties of protein

b. Virus replication

c. Physical & chemical properties

d. Biological properties

14- All DNA viruses are double stranded except:

a. Papovavirus

b. Adenovirus

c. Parvovirus

d. Rotavirus

15- Virus classified by ICTV based on all of the following except:

a. Type and character of viral genome

b. Mode of transmission and pathogenesis

c. The strategy of viral replication

d. Morphology and structure of virion

16- Disease affects central nervous system:

a. Yellow fever

b. Mumps

c. Measles

d. Polio

17- All RNA viruses are single stranded except:

a. Reovirus

b. Coronavirus

c. Orthovirus

d. Filovirus

18- All are TRUE about enterovirus except:

a. These viruses enter the host by ingestion

b. E.g., Rotaviruses

c. Transmitted by droplet infection

d. Replicate primarily in gastrointestinal tract

Genetic variation of viruses 10

Previous exams & Formative:

1- Mutations that can multiply under some conditions but not under other conditions are:

a. Plaque-size mutants

b. Conditional-lethal mutants

c. Host-range mutants

d. Drug-resistant mutants

2- Mutation that induce changes in diameter of the zone of viral lysis in infected cell monolayers are:

a. Plaque-size mutants

b. Conditional-lethal mutants

c. Host-range mutants

d. Drug-resistant mutants

3- A sudden change in the sequence of DNA or RNA is called:

a. Change

b. Alteration

c. Mutation

d. Transduction

Extra:

1- A mutation is defined as:

a. A change in the cells structure

b. Anything that changes in an embryo

c. Any change in the physical features of a human

d. A change in the DNA sequence

2- The mutation results in the replacement of an amino acid codon by a termination (stop) codon called:

a. Host-dependent mutants:

b. Enzyme-deficient mutants

c. Hot mutants

d. None of the above

3- When a single nucleotide base pair is substituted, the type of mutation occurs is:

a. random mutation

b. point mutation

c. inversion

d. mispairing

4- The mutations that are valuable in determining the function of the viral gene is called:

a. Substitution

b. Frameshift mutation

c. Conditional lethal mutation

d. Point mutation

5- Mechanism of virus interference includes all of the following except:

a. Blocking its receptors or by destroying its receptors.

b. The cell enzymes necessary for viral growth are under the direction of the1st virus.

c. The 1st virus stimulates the infected cell to produce an inhibitor (interferon) that prevents the replication of the 2nd virus

d. Phenotypic mixing

6- Between two chromosomes the exchange of gene is called as:

a. Interaction

b. Mutation

c. Recombination

d. Point mutation

7- Drug-resistant mutants are:

a. The mutation usually affects an enzyme that is inhibited by the antiviral drug.

b. mutants occur when a whole segment of the viral genome is lost.

c. Mutations here induce changes in the diameter of the zone of viral lysis seen in infected cell monolayers.

d. All of the above

8- In the virus growth cycle; transmission of the virus particle or the nucleic acid from the surface of the infected cell to the interior of the cells is known as:

a. Penetration

b. Recognition

c. Assembly

d. None of the above

9- When Two viruses enter the same cell, replicate independently and produce their own characteristic type of infection, this is known as:

a. Dual infection

b. Recombination

c. Reassortment

d. Complementation

Previous exams & Formative:

1- Genetic reassortment occurs in:

a. Viruses with segmented genome

b. Defective viruses

c. Viroids

d. Prions

2- Exaltation means:

a. One virus enhances the growth of the other virus

b. No sense mutation

c. Genetic reassortment of virus genome

d. Point mutation in the genome

3- Which of the following is the genome of the virus?

a. DNA

b. RNA

c. DNA or RNA

d. DNA and RNA

Extra:

1- In some mixed infection one virus may enhance the growth of the second virus occurs in:

a. Dual infection

b. Exaltation

c. Recombination

d. Reassortment

2- Two viruses can enter the same cell, replicate independently and produce their own characteristic type of infection in:

a. Dual infection

b. Exaltation

c. Recombination

d. Reassortment

3- Which the This mechanism applies only to viruses with segmented genomes:

a. Exaltation

b. Dual Infection

c. Recombination

d. Reassortment

4- Which This is the way in which defective tumor causing retroviruses propagate and spread in nature:

a. Exaltation

b. Reassortment

c. Interference

d. Complementation

5- In the process of assembly of progeny virions, hybrid capsids constituted by subunits coded by the two different viruses may be generated is:

a. Phenotypic mixing

b. Pseudotype formation

c. All of the above

d. None of the above

6- Phenotypic masking is a:

a. The genetic process resulting in pseudotype formation

b. The genetic process resulting in Phenotypic mixing

c. All of the above

d. None of the above

7- Antigenic drift of viruses is caused by Select one:

a. Recombination

b. Reassortment

c. Mutation

d. Mutation and reassortment

8- All of the following are Mechanisms of viral interference except:

a. One virus may inhibit the ability of the 2nd to adsorb to the cell, either by blocking its receptors or by destroying its receptors

b. The cell metabolites or enzymes necessary for viral growth are taken by or are under the direction of the 1st virus

c. The 1st virus may stimulate the infected cell to produce an inhibitor (interferon) that prevents the replication of the 2nd virus

d. None of the above

9- In Interference the first virus is called:

a. Activated virus

b. Suppressed virus

c. Interfering virus

d. None of the above

10- In Interference the second virus is called:

a. Activated virus

b. Suppressed virus

c. Interfering virus

d. None of the above

Viral replication

Previous exams & Formative:

1- In the virus growth cycle; transmission of the virus particle or the nucleic acid from the surface of the infected cell to the interior of the cells is known as:

a. Penetration

b. Recognition

c. Assembly

d. None of the above

2- Un coating of virus particles occur in:

a. Cell membrane

b. Cytoplasm

c. Nucleus

d. All of the above

3- All of the following are true as regarding properties of virus particles except;

a. They are obligate extracellular pathogens.

b. Viruses have no metabolic activity.

c. They depend on living host cells for providing energy and the synthetic machinery.

d. Virus genome provides the host cell with genetic information needed for its replication

4- Release of progeny virus particles from host cell occur by:

a. Cytolysis

b. Budding

c. Both a and b.

d. None of the above

5- During release of RNA enveloped viruses from host cells, they acquire their envelope from:

a. Nuclear membrane

b. Cell wall

c. Mitochondria

d. Cytoplasmic membrane

6- Reverses transcriptase enzyme is:

a. RNA dependent DNA polymerase.

b. RNA dependent R NA polymerase.

c. DNA dependent DNA polymerase.

d. DNA dependent RNA polymerase.

7- The role of protease enzyme in the virus replication cycle is:

a. Cleavage of precursor polypeptides into functional structural proteins.

b. Facilitate uncoating

c. mRNA transcription

d. None of the above

8- Early synthesized viral proteins are:

a. Envelope glycoproteins

b. Enzymes required for replication of the viral genome.

c. Structural proteins of the progeny virus

d. All of the above.

9- Adsorption of virus particles to host cells characterized by all the following except:

a. Virus and host cell are brought into contact by random collision.

b. Attachment occurs if the host cell membrane contains specific receptors for the virus.

c. The presence of receptors determines the cell tropism and viral

d. Pathogenicity

e. Fusion of viral envelope with cell membrane

10- Which viruses appear to be hypermutable?

a. DNA viruses

b. 'Emerging' viruses

c. Influenza and HIV

d. RNA viruses

11- Genetic variation in viruses contributes to their ability to evade the immune response. Select the principal means by which antigenic shift occurs in influenza A virus:

a. Low fidelity of DNA dependent DNA polymerase.

b. Low fidelity of RNA dependent RNA polymerase.

c. Low fidelity of reverse transcriptase.

d. Reassortment of fragments of the RNA genome.

e. Recombination between RNA genomes

12- When Two viruses enter the same cell, replicate independently and produce their own characteristic type of infection, this is known as:

a. Dual infection

b. Recombination

c. Reassortment

d. Complementation

13- Mechanism of virus interference includes all of the following except:

a. Blocking its receptors or by destroying its receptors.

b. The cell enzymes necessary for viral growth are under the direction of the 1st virus.

c. The 1st virus stimulates the infected cell to produce an inhibitor (interferon) that prevents the replication of the 2nd virus.

d. Phenotypic mixing

14- Reassortment occurs in:

a. Viruses with segmented genome.

b. Defective viruses

c. Host range mutants.

d. Prions

15- Viral genome of one virus that may be encapsulated in the capsid of the second virus is called:

a. Point mutation

b.

c.

EXTRA

1- The viral DNA replicate in:

a. Cytoplasm

b. Vacuole

c. Nucleus

d. Mitochondria

2- The protein coat of the virus remains outside the host cell:

a. True

b. False

3- Viruses require ______ for growth:

a. Bacteria

b. Plants

c. Animals

d. Living cells

4- The first step in infection of a host bacterial cells by a phage is:

a. Adsorption

b. Absorption

c. Penetration

d. Replication

5- In ........... Virus and host cell are brought into contact by random collision:

a. Adsorption

b. Penetration and uncoating

c. Eclipse

d. Assembly

6- In general, most DNA viruses multiply in the host cell's _, while most RNA viruses multiply in the host cell's:

a. Nucleus, cytoplasm

b. Cell membrane, cytoplasm

c. Cytoplasm, nucleus

d. Cytoplasm, cell membrane

7- In DNA viruses (except pox viruses) assembly occurs in:

a. Nucleus

b. Cytoplasm

c. Mitochondria

d. Extracellular

8- How do enveloped viruses exit their host:

a. Rupturing the virus

b. Bursting the host cell

c. Budding or exocytosis

d. None of these are correct

9- Transmission of the virus particle or the nucleic acid from the surface of the infected cell to the interior of the cells in:

a. Adsorption

b. Penetration and uncoating

c. Eclipse

d. Synthesis of new viral components

10- Attachment of the viruses to the cells:

a. random

b. should contain specific receptor

11- Viropexis occurs in:

a. Enveloped viruses

b. Non-enveloped viruses

c. All viruses

d. None of the above

12- Fusion occurs in:

a. enveloped viruses

b. Non-enveloped viruses

c. All viruses

d. None of the above

13- Uncoating of bacteriophage occurs in:

a. Nucleus

b. Cytoplasm

c. Cell surface

d. None

14- Uncoating of poliovirus occurs in:

a. Nucleus

b. Cytoplasm

c. Cell surface

d. None

15- Uncoating of herpes virus occurs in:

a. Nucleus

b. Cytoplasm

c. Cell surface

d. None

16- Synthesis of new viral components It includes synthesis of:

a. Viral nucleic acid

b. Proteins

c. Both viral nucleic acid and proteins

d. None of the above

17- In RNA viruses and pox viruses it occurs in:

a. Nucleus

b. Cytoplasm

c. Mitochondria

d. Extracellular

18- Release of Progeny Virions from the Cell by cytolysis in:

a. Non-enveloped viruses

b. enveloped RNA viruses

c. enveloped DNA viruses

d. none of the above

19- The last step of Viral growth cycle is ......

a. Adsorption

b. Eclipse

c. Release of Progeny Virions from the Cell

d. Assembly