MICROBIOLOGY REVIEW QUIZ 9

                                      Microbiology Quiz-09 Review

1. What is the difference between exotoxin and endotoxin?

Exotoxin

·       Protein released by bacterium during exponential growth phase.

·       Can act at sites other than the location of infection.

·       More potent and more specific than endotoxin

Endotoxin

·       Lipopolysaccharides of gram-negative cell wall

·       Release during lysis initiated by effective host defense or by action of antibiotics

·       Less potent and less specific than exotoxins

2. What are the different types of blood cells?

·       RBC: 4–6 million cells per cubic millimeter

·       WBC: 5000-10000 cells per cubic millimeter

·       Platelets: 150000-450000 cells per cubic millimeter

3. What are the different types of white blood cells?

Granulocyte

·       Neutrophil: most abundant WBC, first line responder and most numerous phagocytes.

·       Eosinophil: Increase in number in hypersensitivity reactions

·       Basophil: Least common. Contains chemical mediators’ histamine and heparin

Agranulocyte

Lymphocyte: Make up 30% to 40% of white blood cells

·       B lymphocytes: Transform into plasma cells and memory cells, produce antibody

·       T lymphocytes: Different types - Helper T cells, Cytotoxic T cells, Suppressor T cells

Monocytes

·       Large circulating phagocytes

·       Leave blood vessel during inflammatory reaction

4. What is antibody? What are the types of antibodies? Mention the character of different types of antibodies?

·       Antibodies are proteins Produced by B-lymphocytes àPlasma cell

·       Also known as immunoglobulins (Ig)

·       They Recognize and bind to foreign antigens

Types of antibodies

·       Ig G: Major antibody in the circulation that can cross the placenta

·       IgA: Present in secretions—tears, saliva, etc. It provides local protection

·       IgM: Largest of the immunoglobulins. It provides first activity in an immune response.

·       IgD: Present in the surface of B cells. It plays a role in B-cell activation

·       IgE: Implicated in allergic reactions.

5. What are the lymphatic organs?

·       Lymph node

·       Tonsils

·       Spleen

·       Thymus

6. Write a short note about thymus gland.

·       Located in the mediastinum

·       Produces thymosins; a hormone that stimulate the maturation of T lymphocytes.

·       Large after birth, capacity slows down during puberty and get atrophy thereafter.

·       Essential in the development of the immune system in the infant.

7. What are the different types of transplants?

·       Autografts: Transplanted from one site of an individual to another site

·       Isografts: Tissues or organs transplanted between identical twins

·       Allografts: Transplants between genetically different individuals

·       Xenografts: Transplants between different species.

8. What is Iatrogenic HAIs?

·       Iatrogenic infections are a set of infections that may result from the use of medical procedures such as the use of catheters, invasive diagnostic procedures, and surgery.

9. What are the portal of entry?

·       Skin

·       Gastrointestinal tract

·       Respiratory tract

·       Urogenital tract

·       Conjunctiva

·       Placenta

10 Define Virulence. What are the virulence factors?

Virulence is the degree of pathogenicity or disease-provoking power of a specific microbe.

Virulence factors

·       Pili: Bacteria must bind to host cell by pili, fimbriae, or specific membrane receptor sites for adhesion.

·       Capsule: A protective outer layer that can help bacteria avoid phagocytosis (engulfment by immune cells).

·       Toxins: Proteins that can damage host cells or interfere with their functions (e.g., exotoxins, endotoxins).

·       Enzymes: Molecules that can break down host tissues or antibodies, aiding in invasion or immune evasion.

·       Flagella: Enable motility and can be used for chemotaxis (movement towards or away from stimuli).

11. What are the different pattern of infection?

·       Local infections: Organism enters the body and remains confined to a specific tissue

·       Focal infections: Pathogen spreads from a local infection to other tissues

·       Systemic infections: Infection spreads to several sites and tissue fluids, usually by the way of the circulatory system.

12. Mention the different category of the disease.

·       Endemic disease: Repeatedly present in a given population or geographical area. An example of an endemic disease is the common cold.

·       Sporadic disease: Breaks out only occasionally. Ex- Typhoid fever in the United States.

·       Epidemic disease: Occurs with greater frequency than usual in a population of a given area

·       Pandemic disease: Is a worldwide epidemic.

13. What are the different lines of defense against microbes?

A. First Line of Defense

Physical barriers

·       Skin, Mucous membranes, ciliary escalator

·       Perspiration, tears, saliva, flow of urine, peristalsis

Chemical barriers

·       PH: Skin, sebaceous and oil glands, mucus.

·       Lysozymes present in perspiration, nasal secretions, saliva, and tears.

B. Second Line of Defense

·       Phagocytosis

·       Inflammation

·       Production of interferons

·       Activation of complement system

C. Third Line of Defense

·       Specific or adaptive defense (Triggered by specific antigen)

·       Cell-mediated and humoral immunity

14. What are the different types of vaccine?

·       Live attenuated: MMR, Varicella, Rotavirus, Oral polio, yellow fever, Influenza (nasal spray).

·       Killed vaccine: Hepatitis A, Rabies, Influenza (flu shot), Hepatitis B, Inactivated polio.

·       DNA vaccines: Recombinant DNA which contain a gene that codes for an antigen.

·       Toxoids: Altered toxins. Example- tetanus, diphtheria, and pertussis.