Jess’s Infection and Response Revision Cards

This set of flashcards covers key concepts related to infection and response, including definitions, mechanisms of disease, and the immune response.

Pathogens

Microorganisms that cause infectious disease, including bacteria, viruses, fungi, and protists.

How do bacteria cause disease?

Bacteria produce toxins that damage tissues and make you feel ill.

How do viruses cause disease?

Viruses live and reproduce inside cells, causing cell damage when they burst out.

Examples of common diseases

Measles – virus; HIV – virus; Salmonella – bacteria; Gonorrhoea – bacteria; Malaria – protist; Rose black spot – fungus.

Symptoms of measles

Fever and red skin rash; can cause blindness or brain damage in severe cases.

HIV transmission

HIV is transmitted through sexual contact or the exchange of body fluids such as blood (e.g., sharing needles).

Late-stage HIV infection

The immune system is so damaged that it cannot fight infections or cancers (AIDS).

Salmonella food poisoning

Caused by ingesting food contaminated with Salmonella bacteria; symptoms include fever, stomach cramps, vomiting, and diarrhoea.

Reducing Salmonella spread

Vaccinating poultry, ensuring proper food hygiene, and thorough cooking.

Gonorrhoea transmission and treatment

Sexually transmitted; treated with antibiotics, though antibiotic resistance is an issue.

Malaria

A protist disease spread by mosquito vectors that transfer the pathogen via blood.

Common symptoms of malaria

Recurrent fevers and fatigue due to bursting of infected red blood cells.

Preventing malaria

Using mosquito nets, insecticides, and antimalarial drugs.

Body's protection from pathogens

The body protects itself through physical and chemical barriers: skin, mucus, cilia, stomach acid.

Main parts of the immune system

White blood cells: phagocytes (ingest pathogens), lymphocytes (produce antibodies and antitoxins).

Function of antibodies

Antibodies bind to specific antigens on pathogens, marking them for destruction.

Function of antitoxins

Antitoxins neutralise toxins produced by bacteria.

How vaccination works

A small, harmless amount of pathogen is introduced to stimulate white blood cells to produce antibodies.

Advantages of vaccination

Vaccination prevents illness, reduces spread, and can lead to herd immunity.

Disadvantages of vaccination

Mild side effects, not always effective, some objections on ethical grounds.

Why antibiotics aren't effective against viruses

Viruses live inside host cells, making them difficult to target without damaging body cells.

Painkillers

Painkillers are used to relieve symptoms but do not cure the underlying disease.

New drug development process

Preclinical testing on cells and animals → clinical trials on humans → double-blind trials for safety and efficacy.

Why drugs are tested

To check for safety, effectiveness, and correct dosage.

What is a double-blind trial?

Neither the patient nor the doctor knows who receives the real drug or placebo to prevent bias.

How to test antibiotic effectiveness

Grow bacteria on agar plates, place antibiotic discs, incubate, measure clear zones where bacteria do not grow.

Reducing spread of communicable diseases

Implementing hygiene, isolation, vaccination, and destroying vectors.

Examples of plant diseases

Tobacco mosaic virus (TMV), rose black spot, and aphid infestations.

Plant physical defences

Cellulose cell walls, waxy cuticle, bark, and leaf fall to remove infected tissues.

Plant chemical defences

Antibacterial chemicals and poisons to deter herbivores.

Plant mechanical defences

Thorns, hairs, and leaves that droop or curl to avoid being eaten.