Infectious Disease and the Immune System

A disease caused by a pathogen, such as bacteria, fungi, protozoa, or viruses.

Any organism or virus that causes disease in another organism.

A type of pathogen that is not considered alive because it cannot perform essential life processes (replication or protein synthesis) on its own.

The process by which a virus enters a host cell and uses the host's enzymes to replicate its own DNA, taking energy and resources away from the host.

Proteins found on the surface of viruses that allow them to attach to specific host cells.

The process where a virus enters a host cell by matching its proteins with complementary proteins on the host cell's membrane.

The genetic material of a virus, which can be either DNA or RNA.

A range of size typically between 20 and 30 nanometers (nm).

The protein coat that encloses a virus's genetic material before it is released from the host cell.

A virus that infects a bacterium.

Bacteriophage DNA that has been incorporated into the host bacteria's circular DNA.

A bacteriophage that specifically infects E. coli bacteria.

A virus that uses the lysogenic cycle.

The process by which a virus bursts out of a host cell, releasing new viral particles.

A virus that acquires an additional membrane from the host cell's plasma membrane.

A virus that does not have an additional membrane from the host cell's plasma membrane.

The viral reproductive cycle where the virus takes over the host cell's machinery and produces new viral particles, ultimately destroying the host cell.

The viral reproductive cycle where the virus's genetic material integrates into the host's DNA and remains dormant, replicating along with the host cell.

The process where unrelated organisms develop similar traits due to adapting to similar environments or selective pressures.

The rapid rate of evolution observed in viruses.

Small infectious agents containing only a short strand of RNA and no protein coat, infecting flowering plants.

Sequences of DNA or RNA that can move around an organism's genome.

Ancient cells that lost their ability to live independently and became dependent on other cells for reproduction.

A process where an activated B-cell makes copies of itself, resulting in numerous identical cells that produce antibodies and memory cells.

A type of B-cell that immediately produces antibodies upon activation, providing short-term immunity to the current infection.

A type of B-cell that 'remembers' a specific pathogen, remaining dormant until re-exposure, then rapidly producing antibodies.

The ability of the immune system to recognize and defend against specific pathogens or antigens.

A substance containing a weakened or inactive form of a pathogen, designed to stimulate an immune response without causing disease.

The process of introducing a vaccine to stimulate immunity.

The collective immunity of a population, where a large percentage of individuals are immune to a disease, preventing its spread.

A measure of the average number of people that an infected person infects.

The ability of a disease to spread from animals to humans.

The ability of a pathogen to infect specific host cells based on recognition of specific antigens.

White blood cells, also known as leukocytes, are responsible for fighting infections and foreign invaders in the body.

The innate immune system provides an immediate, non-specific defense against a broad range of pathogens.

The adaptive immune system mounts a targeted and specific response to individual pathogens, developing memory for future encounters.

Phagocytes are a type of white blood cell that engulf and destroy foreign invaders through a process called phagocytosis.

Macrophages are a type of phagocyte that engulf, digest, and destroy foreign invaders.

Antigens are proteins on cell surfaces that act as identity markers, allowing the immune system to distinguish between self and non-self cells.

Phagocytosis is the process by which phagocytes engulf and destroy foreign invaders through enzymatic breakdown.

The lymphatic system is a network of vessels, tissues, and organs that transports lymph fluid, containing white blood cells and other immune factors, throughout the body.

Lymph nodes are small, bean-shaped organs that filter lymph fluid and house immune cells, particularly lymphocytes.

Antibodies, also known as immunoglobulins, are proteins produced by lymphocytes that specifically bind to antigens on foreign invaders.

Neutralization is a mechanism by which antibodies render pathogens ineffective by blocking their ability to attach to host cells or neutralize toxins.

Opsonization is a process where antibodies coat pathogens, making them more susceptible to phagocytosis by macrophages.

Agglutination is a mechanism by which antibodies cause pathogens to clump together, making them less likely to infect cells and easier for the immune system to remove.

The complement system is a group of proteins that work together to lyse (break down) the membranes of pathogens.

Antigen presentation is the process by which macrophages display fragments of foreign antigens on their cell surfaces, activating helper T-cells.

The process where a gene for antibiotic resistance is passed on to other bacteria through different mechanisms such as conjugative pili, allowing for wider spread of resistance.

The rapid increase in the frequency of a resistance gene within a bacterial population due to the constant exposure to an antibiotic.

A chemical produced by microorganisms that can kill or inhibit the growth of other microorganisms.

The ability of a bacterium to survive and reproduce in the presence of an antibiotic.

A type of genetic material that carries genes for antibiotic resistance and can be transferred between bacteria through conjugation.

A physical connection formed between two bacteria that allows for the transfer of genetic material, including resistance genes.

A type of protein that is essential for blood clotting and is initially inactive in the blood.

An enzyme that converts prothrombin into thrombin, a key step in blood clotting.

A protein that is initially soluble in blood and then converted into insoluble fibrin by thrombin, forming the mesh-like network of a clot.

A fibrous protein that forms a network to trap blood cells and platelets, forming a stable clot to prevent further blood loss and pathogen entry.

Small, irregularly shaped cells in the blood that are essential for blood clotting.

The process of blood clotting, where a cascade of reactions leads to the formation of a clot to seal a wound.

The body's first line of defense against pathogens, primarily consisting of physical barriers like the skin and mucous membranes.

The body's second line of defense, which involves the activation of leukocytes (white blood cells) to fight off infections.

The successful invasion of a pathogen into the body, leading to symptoms of illness.

The process by which populations of organisms change over time due to variations in traits, and the survival and reproduction of those with advantageous traits.

Variations within a species are caused by random changes in the DNA sequence called mutations.

Mutations are more frequent in viruses, especially RNA viruses, since they lack error-checking mechanisms during replication.

The ability of a virus to change its surface proteins, making it harder for the immune system to recognize and fight it.

A process where two different strains of a virus infect the same host, leading to a combination of their genetic material.

The rapid evolution of viruses like influenza is driven by high mutation rates and reassortment, making them difficult to control with vaccines.

Antibiotics are chemicals that inhibit the growth of bacteria, often by disrupting their essential processes like replication, protein synthesis, or cell wall formation.

Antibiotics are ineffective against viruses because viruses don't have the same cellular mechanisms that antibiotics target.

The development of resistance to antibiotics in bacteria is driven by natural selection, where bacteria with mutations that grant resistance survive and reproduce, passing on the resistance trait.

The widespread use of antibiotics in humans and animals has accelerated the evolution of antibiotic-resistant bacteria.

Antibiotic resistance is a major public health threat because it can lead to untreatable bacterial infections, making medical procedures and treatments less effective.

The process by which an organism learns to perform a behavior that is rewarded.

A change in the strength or likelihood of a behavior due to its association with a stimulus.

A type of learning where the learner actively seeks out information and processes it.

A type of learning that occurs through observation and imitation.

A pathogen that can cross the species barrier, infecting both animals and humans.

A pathogen that is capable of infecting multiple host species. This makes them harder to control and can lead to complex transmission pathways.

Increased contact between humans and animals, especially livestock, can lead to a greater chance of zoonotic transmission.

Disruption of animal habitats by human activities can force wildlife to move to areas with higher human populations, increasing the risk of encountering humans and spreading zoonotic diseases.

It is a retrovirus that infects and weakens the immune system, making individuals more susceptible to infections and diseases.

HIV's high mutation rate makes it difficult to develop a long-lasting vaccine and for the immune system to recognize and fight it.

HIV can lead to a severe weakening of the immune system, making individuals vulnerable to opportunistic infections that a healthy immune system would easily combat.

Antiviral drugs can slow down the rate at which HIV destroys lymphocytes, but they cannot completely eliminate the virus.

The COVID-19 pandemic has highlighted the importance of being able to analyze data effectively. Basic math skills, such as calculating percentages and percent change are essential for understanding pandemic-related statistics.