Microbiology and Immunology Quiz

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Questions and Answers

What is the primary function of endospores in certain bacteria?

Identification of bacterial species

Survival during adverse conditions (correct)

Nutrient absorption and synthesis

Reproduction in favorable conditions

Which type of bacteria is characterized by a thick peptidoglycan layer and stains purple?

Gram-positive bacteria (correct)

Mycoplasma bacteria

Capsulated bacteria

Gram-negative bacteria

What distinguishes viruses from living pathogens?

Viruses can reproduce independently

Viruses lack cellular structure (correct)

Viruses can be killed by antibiotics

Viruses have complex metabolic pathways

What is the primary function of the thymus during infancy?

Training lymphocytes, specifically T lymphocytes (C) Signup and view all the answers

What are lipopolysaccharides (LPS) primarily associated with?

Gram-negative bacteria (C) Signup and view all the answers

What happens to the thymus after puberty?

It begins to atrophy (shrink) (A) Signup and view all the answers

Which of the following pathogens is a living organism?

Ascaris lumbricoides (C) Signup and view all the answers

Which type of bone marrow is involved in the production of blood cells?

Red Bone Marrow (A) Signup and view all the answers

What is the primary characteristic of bacteria that lack a cell wall?

They possess sterols for structural support (C) Signup and view all the answers

Which method is effective for killing endospores?

High-pressure steam at 121°C (C) Signup and view all the answers

What role does thymosin play in the immune system?

It aids in the maturation of T lymphocytes (D) Signup and view all the answers

Who is known as the 'Father of Microbiology'?

Antonie van Leeuwenhoek (C) Signup and view all the answers

What role do teichoic acids play in Gram-positive bacteria?

Structure and immune evasion (B) Signup and view all the answers

What significant contribution did Louis Pasteur make to microbiology?

Demonstrated that microorganisms cause disease (D) Signup and view all the answers

What was Joseph Lister known for in the context of surgery?

Introducing aseptic techniques (D) Signup and view all the answers

Which of the following statements describes Robert Koch's contribution to microbiology?

He developed Koch’s Postulates (A) Signup and view all the answers

What component of the immune system is considered the first line of defense against pathogens?

Skin and mucous membranes (B) Signup and view all the answers

Which of the following is NOT a characteristic of the body's second line of defense?

Chemical barriers (B) Signup and view all the answers

What term describes the process where phagocytes stick to the capillary walls near an infection site?

Margination (D) Signup and view all the answers

What is the main purpose of vasodilation during inflammation?

To increase blood flow to deliver more immune cells (A) Signup and view all the answers

Which of the following correctly explains the steps in phagocytosis?

Chemotaxis, adhesion, ingestion, phagolysosome formation (D) Signup and view all the answers

Which type of fluid is characterized by regular leakage and consists of water, ions, and small proteins?

Transudate (A) Signup and view all the answers

What is the primary function of the thymus in the immune system?

Matures T lymphocytes (A) Signup and view all the answers

What are the four classic signs of inflammation?

Calor, dolor, rubor, tumor (D) Signup and view all the answers

What role do lysozymes found in saliva and tears play in the immune response?

Break down bacterial cell walls (A) Signup and view all the answers

Where is the spleen located in the human body?

Upper left abdominal cavity (B) Signup and view all the answers

What are the two types of tissue found in the spleen?

Red pulp and white pulp (C) Signup and view all the answers

Which of the following pathogens is known for being highly transmissible and highly virulent?

Ebola (D) Signup and view all the answers

How does lymph move through the body?

Via unidirectional flow and valves in lymphatic vessels (C) Signup and view all the answers

What role do tonsils serve in the immune system?

Screen pathogens entering through air and food (C) Signup and view all the answers

What happens to individuals after a splenectomy concerning their immune response?

They may be more vulnerable to infections (A) Signup and view all the answers

What distinguishes extracellular fluid (ECF) from intracellular fluid (ICF)?

ECF is divided into two categories, while ICF is considered singular (B) Signup and view all the answers

What is the primary function of pyrogens in the immune response?

Raise body temperature to slow pathogen growth (C) Signup and view all the answers

Which type of antibody is primarily responsible for long-term immunity?

IgG (A) Signup and view all the answers

What role do major histocompatibility complexes (MHC) play in the immune system?

Present antigens to T cells (C) Signup and view all the answers

What structure is unique to the Fab region of an antibody?

It binds to antigen-specific sites (C) Signup and view all the answers

Which immune cells function as antigen presenting cells (APCs)?

Macrophages, dendritic cells, and B cells (C) Signup and view all the answers

What is the main function of complement proteins in the immune system?

Enhance inflammation and promote phagocytosis (B) Signup and view all the answers

Which antibody type is primarily involved in allergic reactions?

IgE (D) Signup and view all the answers

What is the process called when antibodies coat pathogens to enhance phagocytosis?

Opsonization (A) Signup and view all the answers

What role does the capsid serve in a virus?

It protects the viral genome and assists in attachment to host cells. (C) Signup and view all the answers

What distinguishes an enveloped virus from a naked virus?

Enveloped viruses have a membrane envelope derived from host cell components. (C) Signup and view all the answers

Which enzyme is specifically associated with retroviruses?

Reverse transcriptase (B) Signup and view all the answers

What occurs after viral DNA from a retrovirus integrates into the host's genome?

The host cell produces viral proteins and new virus particles. (B) Signup and view all the answers

Which of the following is NOT a symptom of prion infection?

Flu-like symptoms (B) Signup and view all the answers

How do enzymes, when present in some viruses, contribute to viral replication?

They aid in copying RNA or converting it to DNA. (C) Signup and view all the answers

What is the primary function of spikes in a virus?

To enable attachment to specific receptors on the host cell. (D) Signup and view all the answers

Which characteristic is unique to retroviruses compared to other viruses?

They contain RNA as their genetic material. (A) Signup and view all the answers

Study Notes

Blood Components

Formed elements make up 44% of blood, including red blood cells (RBCs), white blood cells (WBCs), and platelets.
The remaining 55% is plasma, containing nutrients, electrolytes (like sodium, potassium, and chloride), nitrogenous waste products (urea), and dissolved gases.

Red Blood Cell Structure and Function

RBCs are biconcave disks.
Lacking organelles, they use anaerobic respiration.
This shape maximizes surface area for gas exchange.
Hemoglobin, containing iron, facilitates oxygen transport.
Lifespan is ~120 days.

Hematopoiesis

Hematopoiesis is the production of red blood cells in red bone marrow.
It occurs constantly due to RBCs' inability to reproduce.
It is hormonally controlled.

White Blood Cell Types and Function

Granulocytes:
- Neutrophils: Most abundant (70%), first responders to infections, phagocytic.
- Eosinophils: Fight parasitic infections and regulate allergic reactions (acidic-red).
- Basophils: Involved in inflammatory responses (basic blue).
Agranulocytes:
- Lymphocytes: Produce antibodies (B cells) and destroy infected cells (T cells); spherical nucleus.
- Monocytes: Differentiate into macrophages for long-lasting immune responses; large, U-shaped nucleus.

White Blood Cell Production

WBC production is stimulated by colony-stimulating factors released from red bone marrow.

Platelets in Blood Clotting

Platelets initiate hemostasis (stopping blood loss) through vascular spasm, platelet plug formation, and clot formation.
The process involves converting prothrombin to thrombin, and fibrinogen to fibrin.

Immune System Components

Intracellular Fluid (ICF): Fluid inside cells.
Extracellular Fluid (ECF): Fluid outside cells, divided into plasma and interstitial fluid.
Tissue Fluid Types: Transudate (regular leakage) and Exudate (during inflammation).

Lymphatic Drainage

Interstitial fluid enters lymphatic capillaries and becomes lymph.
Lymph flows through vessels with valves, filtered by lymph nodes.
Two main lymphatic ducts: right lymphatic duct and thoracic duct.

Tonsils

Tonsils (pharyngeal, palatine, lingual) help screen pathogens entering from air/food.

Primary and Secondary Immune Organs

Primary: Thymus and bone marrow.
Secondary: Spleen and lymph nodes.

Spleen Function

Filters blood (not lymph).
Destroys old or damaged RBCs.
Acts as a blood reservoir.
Contributes to immune competence.

Thymus Function

Located in the superior mediastinum.
Important for T lymphocyte maturation.
Aids in the development of self-tolerance (preventing autoimmune disorders).
Produces thymosin (hormone).

Red Bone Marrow Function

Produces blood cells (hematopoiesis) from hematopoietic stem cells.

Pathogens

Living: bacteria, fungi, protozoa, parasitic animals.
Non-living: viruses, prions.

Bacterial Cell Wall

Peptidoglycan provides structural support and protection from osmotic pressure.
Gram-positive bacteria: Thick peptidoglycan layer.
Gram-negative bacteria: Thin peptidoglycan layer with an outer membrane (endotoxins).
Mycoplasma lack a cell wall; some bacteria possess a capsule.

Sterilization Methods

Autoclaving (high-pressure steam at 121°C) is used to kill endospores.

Types of Antibiotics

Bactericidal: Kill bacteria directly, inhibiting cell wall synthesis (penicillins, cephalosporins), or altering ribosomes (streptomycin)
Bacteriostatic: Inhibit bacterial growth by blocking protein synthesis (tetracyclines), folic acid production (sulfonamides), or DNA replication (trimethoprim).
Broad-spectrum: Affect many types of bacteria.
Narrow-spectrum: Affect a smaller range of bacteria.

Antibiotic Resistance

Antibiotic resistance arises from bacterial mutations, overuse, and incomplete courses.
Common resistant strains include MRSA (methicillin-resistant Staphylococcus aureus) and MDR-TB (multidrug-resistant tuberculosis).

Discovery of Penicillin

Alexander Fleming's accidental discovery of penicillin from Penicillium notatum.

Virus Structure

Viruses consist of a nucleocapsid (genome + capsid), and sometimes, an envelope.
The capsid protects the genetic material.
Envelopes derive from host cells.
Spikes (glycoproteins) on the envelope aid in attachment to host cells.

Retroviruses

Retroviruses use reverse transcriptase to convert RNA to DNA and integrate it into the host's genome.
HIV is an example.

Prions

Misfolded proteins causing fatal neurodegenerative diseases (e.g., Creutzfeldt-Jakob disease, Mad Cow disease).

Immune System Defense Mechanisms

First Line: Skin, mucus membranes, chemical barriers (acidic pH), and beneficial microbiota.
Second Line: Phagocytosis, inflammation, fever, and antimicrobial proteins.
Third Line: Antibody-mediated immunity and cell-mediated immunity.

Antibody Structure and Function

Y-shaped protein with two heavy and two light chains, including Fab (variable antigen-binding region) and Fc (constant region).
Classified into IgG, IgA, IgM, IgE, and IgD, with different functions based on location and role in immune responses like opsonization and agglutination.

Antigen-Presenting Cells (APCs)

Cells (macrophages, dendritic cells, B cells) that process and present antigens to T cells through MHC molecules.

Primary vs. Secondary Immune Responses

Primary: First encounter with an antigen; slow response, IgM first, then IgG production.
Secondary: Subsequent encounters; faster and stronger response, IgG-dominated.

Immunity

Natural: Acquiring immunity through infection or maternal antibodies.
Artificial: Acquiring immunity through vaccines or immune serum.
Active: Acquiring immunity through exposure to the antigen, inducing immune responses.
Passive: Acquiring immunity through obtaining pre-formed antibodies.

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Description

Test your knowledge on key concepts in microbiology and immunology. This quiz covers topics like endospores, Gram-positive bacteria, and immune system functions. Challenge yourself with questions about historical contributions to the field and essential biological components.