Biology Infection and Response

Communicable disease

Diseases that can easily spread from one person to another.

Pathogen

Any microorganism that can produce disease.

Pathogenicity

How pathogenic a microorganism is.

Bacterial pathogens

Prokaryotic, unicellular organisms that can produce toxins (e.g., salmonella).

Viral pathogens

Not cells, they invade cells, duplicate, and burst them to release new viruses (e.g., measles).

Protist pathogens

Eukaryotic, unicellular organisms transferred by vectors (e.g., malaria).

Fungi pathogens

Eukaryotic organisms that can be multicellular or single-celled (e.g., athlete's foot).

Transmission of pathogens

Pathogens can spread through air, contact, poorly prepared food, water, and vectors.

Hygiene in disease prevention

Practices such as washing hands and covering mouth that help reduce disease spread.

Immune system

The system used by the body to protect itself after a pathogen overcomes physical defenses.

Malaria life cycle

Malaria parasites reproduce asexually in human liver and red blood cells but undergo sexual reproduction in mosquitoes.

Antibodies

Proteins produced by white blood cells that neutralize pathogens.

Vaccination

Introducing a weakened pathogen to stimulate the immune system and create immunity.

Herd immunity

Protection given to a population against disease when a high percentage are vaccinated.

Antibiotic resistance

Occurs when bacteria mutate and survive antibiotic treatment, passing resistant genes to offspring.

Monoclonal antibodies

Antibodies produced from a single clone of cells, used in treatments and diagnostic tests.

Aphids

Insects that feed on plant sap and can act as vectors for diseases.

Plant nitrate ions

Essential for converting sugars into proteins; their deficiency stunts growth.

Magnesium ions

Necessary for making chlorophyll; deficiency causes yellowing of leaves (chlorosis).

Double-blind trial

A study where neither the doctor nor the patient knows if they receive the actual drug or a placebo.

Placebo effect

A beneficial effect produced by a placebo, attributed to patient belief in the treatment.

Phagocytes

White blood cells that engulf and destroy microorganisms through phagocytosis.

Lymphocytes

A type of white blood cell that produces antibodies specific to pathogens.

Antitoxins

Substances produced to counteract toxins released by pathogens.