Basic Immunology Practice Flashcards

A comprehensive set of question-and-answer flashcards covering key topics in basic immunology, including pathogens, bacterial and viral structures, the immune system, vaccination, and antibiotics.

What is the primary difference between infectious and non-infectious diseases?

Infectious diseases are caused by pathogens and can be transmitted from person to person, whereas non-infectious diseases are not caused by pathogens and cannot be spread from one person to another.

What is the difference between a sign and a symptom?

A sign can be observed or measured (e.g., rashes, fever), while a symptom is described or felt by the patient (e.g., headaches, fatigue).

What are four ways infectious diseases can be spread?

1. Airborne droplets 2. Direct contact 3. Contaminated food and water 4. Disease vectors.

What is a disease vector?

Any organism that acts as a carrier of an infectious disease between organisms of a different species, such as the Aedes mosquito carrying the dengue virus.

Identify four examples of non-infectious diseases mention in the notes.

1. Coronary heart disease 2. Type 2 diabetes 3. Sickle-cell anaemia 4. Atherosclerosis.

What are the standard structural features of a typical bacterial cell?

A small, unicellular organism with a peptidoglycan cell wall, circular DNA, $70S$ ribosomes, and a lack of membrane-bound organelles.

Name the three shapes of prokaryotic cells identified in the text.

1. Bacillus (rod-shaped) 2. Coccus (spherical) 3. Spirillum (spiral).

How do bacterial cells reproduce?

Through a process called binary fission.

In terms of size, how do prokaryotic cells compare to eukaryotic cells?

Prokaryotic cells are typically smaller ($< 5 \text{ }μ\text{m}$ in diameter) than eukaryotic cells ($> 10 \text{ }μ\text{m}$ in diameter).

Where is the genetic material located in prokaryotes versus eukaryotes?

In prokaryotes, DNA is in the nucleoid region; in eukaryotes, DNA is in the nucleus surrounded by a nuclear envelope.

What is the specific causative agent of pneumococcal disease?

The bacterium Streptococcus pneumoniae.

How is Streptococcus pneumoniae transmitted?

Through respiratory droplets and from contaminated objects or surfaces; infection occurs when inhaled droplets reach the alveoli.

Why are viruses described as obligate intracellular parasites?

They can only reproduce within a host cell because they lack cellular components and metabolic enzymes to synthesize proteins or carry out metabolism independently.

What characterizes the extracellular state of a virus?

The virus particles (virions) are metabolically inert.

What are the two primary components that make up a basic virus structure?

Genetic material (nucleic acid) enclosed within a protein coat (capsid).

In the structure of the influenza virus, what are the roles of Hemagglutinin and Neuraminidase?

Hemagglutinin attaches the virus to a host cell for entry, while Neuraminidase is an enzyme important for the release of newly formed viruses.

What distinct physical signs help distinguish influenza from a common cold?

High fever (between $39^{\text{o}}\text{C}$ and $41^{\text{o}}\text{C}$) and the lack of excessive mucus production.

From which stem cells do all blood cells arise, and where are they found?

Hematopoietic stem cells (HSCs) found in the bone marrow.

What are the distinct characteristics of a neutrophil's nucleus and its function?

It has a multi-lobed nucleus and functions to engulf and destroy foreign bodies via phagocytosis.

How do B lymphocytes contribute to the immune response?

They mature into plasma B cells that produce and secrete antibodies, or into memory B cells that provide long-term immunity.

Describe the structural appearance of a macrophage.

It has a kidney bean-shaped nucleus and contains few or no granules.

How do vaccines prevent infectious diseases?

They contain an agent resembling a pathogen that stimulates B lymphocytes to differentiate into plasma B cells to produce antibodies and form memory B cells for future protection.

Why are antibiotics ineffective against viruses?

Antibiotics target cellular structures and metabolic pathways specific to bacteria (like cell wall synthesis or $70S$ ribosomes), which viruses do not possess.

How does penicillin specifically kill bacteria?

It inhibits the synthesis of the peptidoglycan cell wall, causing the cell to expand, lyse, and die as water enters via osmosis.

How does the misuse of antibiotics lead to the emergence of "superbugs"?

If a course is insufficient to kill all bacteria, those with mutations for resistance survive and multiply, passing the resistant genes to the next generation.

What is the difference between active and passive immunity?

Active immunity is gained when an immune response is triggered and the body produces its own antibodies; passive immunity is gained by receiving antibodies from an external source (e.g., mother to child).

Define artificial active immunity.

Immunity gained through vaccination, where the body is intentionally exposed to a pathogen-resembling molecule to trigger its own antibody production.