Lect.

5 : Bacterial Genetics
1. Which of the following has no cell wall?
a) E. coli
b) Mycobacterium
c) Mycoplasma
d) Streptococcus
Correct answer: c) Mycoplasma

2. Teichoic and Lipoteichoic acids are present in which type of cell wall?
a) Gram-negative
b) Gram-positive
c) Mycobacteria
d) Fungi
Correct answer: b) Gram-positive

3. Which of the following contains the largest amount of normal flora?

a) Stomach
b) Small intestine
c) Colon
d) Skin
Correct answer: c) Colon

4. Which of the following is a cell of innate immunity?

a) B cells
b) T cells
c) Neutrophils
d) Plasma cells
Correct answer: c) Neutrophils

5. In which phase are the new cells equal to the dying cells?
a) Lag phase
b) Log phase
c) Stationary phase
d) Death phase
Correct answer: c) Stationary phase

6. Which one of the following can only grow in the presence of oxygen?
a) Facultative anaerobes
b) Obligate anaerobes
c) Microaerophiles
d) Obligatory aerobes
Correct answer: d) Obligatory aerobes

7. In which phase are dying cells more than newly formed cells?
a) Lag phase
b) Log phase
c) Stationary phase

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Lect.5 : Bacterial Genetics
d) Death phase

Correct answer: d) Death phase

8. Which of the following has no cell wall?

a) E. coli
b) Mycobacterium
c) Mycoplasma
d) Streptococcus
Correct answer: c) Mycoplasma
9. Teichoic and Lipoteichoic acids are present in which type of cell wall?
a) Gram-negative
b) Gram-positive
c) Mycobacteria
d) Fungi
Correct answer: b) Gram-positive
10. Which of the following contains the largest amount of normal flora?
a) Stomach
b) Small intestine
c) Colon
d) Skin
Correct answer: c) Colon
11. Which of the following is a cell of innate immunity?
a) B cells
b) T cells
c) Neutrophils
d) Plasma cells
Correct answer: c) Neutrophils
12. In which phase are the new cells equal to the dying cells?
a) Lag phase
b) Log phase
c) Stationary phase
d) Death phase
Correct answer: c) Stationary phase
13. Which one of the following can only grow in the presence of oxygen?
a) Facultative anaerobes
b) Obligate anaerobes
c) Microaerophiles
d) Obligatory aerobes
Correct answer: d) Obligatory aerobes

14. Regarding the adaptive specific immune system, which of the following statements is correct?
a) A targeted and non-specific response to a single pathogen or molecule
b) A generalized and non-specific set of defenses against a class or group of pathogens
c) A set of barrier mechanisms that adapts to specific pathogens after repeated exposure

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Lect.5 : Bacterial Genetics

d) The production of antibody molecules against pathogens

Correct answer: d) The production of antibody molecules against pathogens

15. Which one of the following sets of chemical and biochemical inhibitors act as a first line in
innate immunity?
a) Lysozyme in tears and HCl in lungs
b) Proteolytic enzyme in intestine and acidic pH of saliva
c) Lysozyme in tears and HCl of the stomach
d) Hydrolytic enzymes in saliva and HCl of tears
Correct answer: c) Lysozyme in tears and HCl of the stomach

16. Regarding the cell wall structure of Gram-negative bacteria, which one of the following
statements is most accurate?
a) The peptidoglycan layer is the major constituent (50%-80%)
b) The outer membrane is a phospholipid bilayer composed of an inner and outer leaflet
c) The teichoic acids are the major surface antigen
d) The lipoprotein is responsible for the toxicity

Correct answer: b) The outer membrane is a phospholipid bilayer composed of an inner and
outer leaflet

17. Which one of the following statements is correct regarding transposons?

a) They encode enzymes that degrade the ends of the bacterial chromosome
b) They are a family of transfer RNAs
c) They are short sequences of RNA
d) They are short sequences of DNA that often encode enzymes that mediate antibiotic
resistance

Correct answer: d) They are short sequences of DNA that often encode enzymes that mediate
antibiotic resistance

18. Regarding Streptococcus viridans, which of the following is most accurate?

a) It is a pathogenic microorganism
b) It can cause skin infection
c) It is a normal flora in the mouth
d) It is a normal flora in the skin
Correct answer: c) It is a normal flora in the mouth

19. Organisms that can grow in the presence of a little amount of oxygen are called:
a) Obligate aerobes
b) Microaerophilics
c) Obligate anaerobes
d) Facultative anaerobes
Correct answer: b) Microaerophilics

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Lect.5 : Bacterial Genetics
20. The relationship of an organism and host cell which is characterized by the exchange of benefits
from each other is called:
a) Parasitism
b) Commensalism
c) Mutualism
d) Amensalism
Correct answer: c) Mutualism

21. The component of typical bacteria that determines the shape of their cell is:
a) The inner membrane
b) The cell wall
c) The cytoplasmic membrane
d) The outer membrane
Correct answer: b) The cell wall
22. Which of the following statements about plasmids is correct?
a) It consists of genetic information and is found in eukaryotes.
b) It is a strand of DNA that carries the essential genetic information.
c) Present in cytoplasm that carries the gene essential for antibiotic resistance.
d) It is the main chromosome in Gram-negative bacteria.

Correct answer: c) Present in cytoplasm that carries the gene essential for antibiotic
resistance.

• Which one is most dangerous to the host? →Answer: Parasitism

• Streptococcus mutans normal flora location:→Answer: Teeth
• These organisms grow best in the presence of little oxygen? →Answer: Microaerophilics

1. **The bacteria is multiplied by:**

a) Spore formation
b) Conjugation
c) Gametes
d) Simply binary fission
**Correct answer: d) Simply binary fission**

2. **One of the following is a chief distinguishing characteristic of eukaryotes:**

a) They have no nucleus
b) They contain organelles
c) They divide by binary fission
d) They have true nucleoli
**Correct answer: d) They have true nucleoli**

3. **The 80s ribosome is found in which of the following cells?**

a) Eukaryote cells
b) Viruses
c) Animal cells

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Lect.5 : Bacterial Genetics
**Correct answer: a) Eukaryote cells**

4. **What is the structure that protects bacteria from host defenses and harmful substances, and is
called a slime layer?**
a) Capsule
b) Flagella
c) Spore
d) Fimbriae
**Correct answer: a) Capsule**

5. **What is the name of bacteria with one flagellum on each side?**

a) Peritrichous
b) Lophotrichous
c) Monotrichous
d) Amphitrichous
**Correct answer: d) Amphitrichous**

6. **Which one of these organisms contains Mycolic acid?**

a) Mycobacterium
b) Bacillus anthracis
c) Clostridium botulinum
d) Streptococcus pyogenes
**Correct answer: a) Mycobacterium**

7. **The shape of bacilli bacteria is:**

a) Circular shape
b) Rod shape
c) Cocci shape
d) Spiral shape
**Correct answer: b) Rod shape**

8. **What group of bacteria did we find that lacked peptidoglycan on their cell wall?**
a) G+ve bacteria
b) G-ve bacteria
c) Viruses
d) Parasite
**Correct answer: b) G-ve bacteria**

9. **Teichoic acid is considered unique for:**

a) Virus
b) Parasite
c) G+ve bacteria
d) G-ve bacteria
**Correct answer: c) G+ve bacteria**

10. **The cell may be unicellular or multicellular, and many may be dimorphic:**
a) Bacteria

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Lect.5 : Bacterial Genetics
b) Virus
c) Protozoa
d) Fungi
**Correct answer: d) Fungi**

**1. In which type of bacterial cell wall are teichoic acid and lipoteichoic acid present?**
a) Gram-negative
b) Gram-positive
c) Fungi
d) Viruses

**Correct answer:** b) Gram-positive

**2. The site that is considered sterile from normal flora in the human body is:**
a) Skin
b) Lungs
c) Muscles
d) Intestines

**Correct answer:** c) Muscles

**3. Which of the following organisms is more common as normal flora in the colon?**
a) Staphylococcus aureus
b) Escherichia coli
c) Clostridium difficile
d) Lactobacillus

**Correct answer:** b) Escherichia coli

**5. The endotoxin produced by Gram-negative bacteria is present in:**

a) Lipoproteins
b) Lipopolysaccharides
c) Teichoic acid
d) Glycolipids

**Correct answer:** b) Lipopolysaccharides

**6. The species of Lactobacillus which decreases the pH of its original sites colonizes in:**
a) Stomach
b) Small intestine
c) Vagina
d) Oral cavity

**Correct answer:** c) Vagina

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Lect.5 : Bacterial Genetics

8. The bacterial capsule present in some bacteria as a non-essential component is used for:
a) Reproduction
b) Adherence and protection
c) Protein synthesis
d) Metabolism
Correct answer: b) Adherence and protection

9. An outbreak of post-surgical wound infection caused by Staphylococcus aureus has occurred in the
hospital. Using your knowledge of normal flora, which one of the following body sites is the more likely
location for this organism?
a) Skin
b) Mouth
c) Nose
d) Intestines
Correct answer: c) Nose

10. It consists of specialized cells, organs, tissues, and proteins designed to identify and destroy
foreign bodies and abnormal substances before they can damage the body. This is called the:
a) Circulatory system
b) Digestive system
c) Respiratory system
d) Immune system
Correct answer: d) Immune system

1. Which of the following differentiates bacteria into two main classes?

a) Capsule stain
b) Endospore stain
c) Gram stain
d) Acid-fast stain
Correct answer: c) Gram stain

2. What is the relationship between the microorganisms and the host that affects the host harmfully?
a) Commensalism
b) Mutualism
c) Parasitism
d) Symbiosis
Correct answer: c) Parasitism

3. In which stage are bacteria more infective?

a) Lag phase
b) Stationary phase
c) Death phase
d) Log phase
Correct answer: d) Log phase

4. What is the most common bacteria in the colon?

a) Escherichia coli
b) Staphylococcus aureus
c) Bacillus subtilis
d) Lactobacillus
Correct answer: a) Escherichia coli

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Lect.5 : Bacterial Genetics
5. Lipo-oligosaccharides are present in gonococci, but what is present in meningococci?
a) Lipopolysaccharide
b) Peptidoglycan
c) Capsule
d) Teichoic acid
Correct answer: a) Lipopolysaccharide

6. What is the total genetic material of bacteria called?

a) Plasmid
b) Chromosome
c) Genome
d) Nucleoid
Correct answer: c) Genome

7. Which component of bacteria contains the resistant gene for antibiotics?

a) Capsule
b) Plasmid
c) Cell wall
d) Flagella
Correct answer: b) Plasmid

8. The total DNA material of bacteria consists of?

a) Chromosome + plasmid
b) Nucleoid + ribosomes
c) Plasmid + cytoplasm
d) Ribosomes + chromosome

22. The main function of the capsule is?

a) Protection
b) Reproduction
c) Motility
d) Communication
Correct answer: a) Protection

23. The classification of bacteria depends on the ____________ layer in the cell wall?
a) Peptidoglycan
b) Lipid
c) Protein
d) Lipopolysaccharide
Correct answer: a) Peptidoglycan

24. The major surface antigen of Gram-positive bacteria is?

a) Teichoic acid
b) Lipopolysaccharide
c) Capsule
d) Flagella
Correct answer: a) Teichoic acid

4. The typical bacteria are differentiated into two main groups based on:
a) Acid fast stain
b) Malkite green stain
c) Giemsa stain
d) Gram stain
Correct answer: d) Gram stain

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Lect.5 : Bacterial Genetics
19. Escherichia coli is the most common bacteria that can cause urinary tract infection, it is
considered as:
a) Gram positive bacilli
b) Gram negative bacilli
c) Gram negative cocci
d) Gram positive cocci
Correct answer: b) Gram negative bacilli

3. The major constituent of the peptidoglycan layer in Gram-positive bacteria is:

a) 7% to 55%
b) 50% to 89%
c) 50% to 80%
Correct answer: c) 50% to 80%

4. The major surface antigen of Gram-positive bacteria is:

a) Teichoic
b) Teichoic and Lipoteichoic
c) Lipoteichoic
Correct answer: b) Teichoic and Lipoteichoic

5. What is a protein that stabilizes the outer membrane and fixes it to peptidoglycan?
a) Lipoprotein
b) Essential protein
c) Semi-essential protein
Correct answer: a) Lipoprotein

6. Which is responsible for the toxicity of Gram-negative bacteria?

a) T cytotoxin
b) Lipid A
c) Toxins
Correct answer: b) Lipid A

7. Which is the major surface antigen of Gram-negative bacteria?

a) Lipopolysaccharide
b) Lipoteichoic
c) Polysaccharide O-antigen
Correct answer: c) Polysaccharide O-antigen

8. Where is the location of the O antigen and the internal toxins in Gram-negative bacteria?
a) LPS
b) LBS
c) LSS
Correct answer: a) LPS

1. What is the entry of a new organism and multiplication on the body surface (like on the skin, mouth,
intestines) without causing infection or disease?
a) Infection
b) Colonization
c) None of the above
Correct answer: b) Colonization

2. Growth and multiplication of a microbe in or on the body of the host with the production of disease.

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Lect.5 : Bacterial Genetics
a) Infection
b) Colonization
c) None of the above
Correct answer: a) Infection

3. Resident flora consists of organisms that are regularly present in a given area, for example:
a) E. coli
b) Meningococcus
c) None of the above
Correct answer: a) E. coli

4. The consists of both pathogenic and non-pathogenic organisms that inhabit the skin or mucous
membrane for a limited time.
a) Transient Flora
b) Resident Flora
c) Meningococcus
Correct answer: a) Transient Flora

5. The normal flora of the large intestine benefits from each other, which is correct?
a) Commensalism
b) Mutualism
c) None of the above
Correct answer: b) Mutualism

6. The microbe receives benefit but does harm or benefit the host. They are called:
a) Commensalism
b) Mutualism
c) None of the above
Correct answer: a) Commensalism

7. Skin yeast, if it enters the person’s bloodstream when needles penetrate the skin and cause
endocarditis, peritonitis. Which of the following is the yeast?
a) Streptococcus
b) Candida albicans
c) None of the above
Correct answer: b) Candida albicans

1. Function of immune system?

• A: Defends body against foreign invaders
• B: Toxin stimulates
• C: None of the above
Answer: A

2. Which of the following Chemical & biochemical inhibitors?

• A: Hydrolytic enzymes in saliva
• B: Blinking reflex and tears
• C: Dendritic cells
Answer: A

3. Which of the following cells of Innate immunity?

• A: Natural killer (NK) cells
• B: Hydrolytic enzymes in saliva
• C: Blinking reflex and tears
Answer: A

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Lect.5 : Bacterial Genetics

4. Which of the following Mechanical barriers?

• A: Natural killer (NK) cells
• B: Coughing and sneezing reflex
• C: Acidic pH in the adult vagina
Answer: B

5. Which of the following Acute phase protein?

• A: Coughing and sneezing reflex
• B: Acidic pH in the adult vagina
• C. Complemet
Answer: C

10. Is made up of T and B lymphocytes and has an active immune response through humoral and cell-
mediated pathways.
• A: Spleen
• B: Red pulp
• C: White pulp
Answer: C

11. Cells, situated in mucous membranes, endocytose antigens from the lumen of the digestive,
respiratory, and urogenital tracts. Which of the following is this?
• A: T-cells
• B: B-cells
• C: M-cells
Answer: C

12. "The cell of innate immunity stimulates adaptive immunity?"

A. Macrophage
B. Neutrophil
C. Basophil
D.NK cell

....... doesn't have a membrane and no nucleus.

• A) bacteria
• B) animal
• C) plant
• D) fungi
Answer: A) bacteria
Is a type of bacteria, it is the smallest bacteria
• A) Borrelia
• B) RBC
• C) E.coli
• D) mycoplasma
Answer: D) mycoplasma
It gives bacteria gram + or -
• A) cytoplasmic membrane
• B) peptidoglycan
• C) plasmids
• D) capsule
Answer: B) peptidoglycan
Peptidoglycan found in:
• A) cell wall
• B) capsule

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Lect.5 : Bacterial Genetics
• C) pili
• D) pilus
Answer: A) cell wall

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