Health, disease and the development of medicines Study Guide

Infections are caused by pathogenic microorganisms. These pathogens include bacteria, viruses, fungi, and protists, each causing specific diseases with distinct symptoms and effects on their hosts. Understanding the characteristics of these common infections is crucial for their prevention, diagnosis, and treatment. For example, bacterial infections like cholera target the digestive system, leading to severe dehydration, while tuberculosis primarily damages the lungs. Fungal infections, such as Chalara ash dieback, impact plants, causing tissue damage. Protists, like those causing malaria, invade blood cells and the liver. Viruses, exemplified by HIV, compromise the immune system by attacking white blood cells, eventually leading to AIDS.

Antibiotics are a class of antimicrobial drugs specifically designed to combat bacterial infections. Their effectiveness stems from their ability to target and interfere with biological processes vital to bacteria, but which are either absent or sufficiently different in human cells. For instance, many antibiotics inhibit bacterial cell wall synthesis. Bacterial cells possess a rigid cell wall, which human cells lack. By preventing its formation or damaging its structure, the antibiotic weakens the bacterium, leading to its death. Other antibiotics might target bacterial protein synthesis by binding to bacterial ribosomes, which differ structurally from human ribosomes. This specificity is crucial; it allows antibiotics to eliminate the invading bacteria without causing significant harm to the host’s cells. This fundamental difference means antibiotics are ineffective against viral infections or other types of pathogens, as these organisms do not share the targeted bacterial processes.