OVERMUGGED 2024 S3 IP NYGH Biology WA2 Revision - Worksheet

REVISION WA2 SEC 3 & SEC 4 KOVAN | BUKIT TIMAH | MARINE PARADE 87702540 OVERMUGGED@GMAIL.COM WWW.OVERMUGGED.COM FOLLOW US ON IG:

© OVERMUGGED | www.overmugged.com | 2024 1 UPPER SECONDARY IP BIOLOGY Infectious Diseases in Humans NYGH S3 WA2 Revision Name: Date: What are pathogens? Pathogen Acellular Virus Prion Cellular Prokaryotic Bacteria Eukaryotic Fungi Protozoa Helminth Algae

© OVERMUGGED | www.overmugged.com | 2024 2 Prion diseases All cell membranes have proteins embedded within for a variety of functions. Prions form when proteins in the brain misfold or mutate into different structures and conformations. These abnormal proteins cause prion diseases (also known as transmissible spongiform encephalopathy, TSE) that are transmissible and unfortunately, untreatable. Some studies have hypothesised that these abnormal proteins may bind to and induce other proteins to also undergo a conformational change. This could result in a chain reaction that propagates the growth of prions and accelerates the progression of the diseases it causes. Prion diseases are rare , affecting approximately 0.0002% of the global population yearly, and are either inherited or acquired . However, prion diseases may even occur without inheriting a genetic muation or exposure to prion infections. Prion disease Characteristics Creutzfeldt-Jakob Disease (CJD) Severe, rapid onset, fatal Cognitive impairment Muscle atrophy Personality changes Kuru Non-immunogenic Arose from ritualistic consumption of tissues from recently deceased family members (including the brain) Loss of bodily control Behavioural changes Random compulsive laughing or crying Bovine Spongiform Encephalopathy (BSE) “Mad Cow disease” Abnormal posture Coordination problems and difficulty in rising Decreased milk production Mad Cow disease: https://youtu.be/Pxojz6grwcU

© OVERMUGGED | www.overmugged.com | 2024 3 Pathogens Pathogen Characteristics Parasitic worm/helminth Worm-like parasite Invertebrates with elongated, flat, or round bodies Complex life cycle involving hosts Helminths: Intestinal Nematodes: https://youtu.be/O1qf3R3zMB0 Colonoscopy Demonstrating a Moving Worm | NEJM: https://youtu.be/AZr36qP14p4 Protozoa Unicellular eukaryotes Individual organisms or parasitic Motile via use of flagella, pseudopodia, or cilia Fungi Eukaryotic Unicellular (yeast) and multicellular (mushrooms, molds) Absorb nutrients from immediate surrounding Prokaryote Cells without endomembrane systems Short generational times result in overwhelming infection rates Adapt to host immune system defenses quickly Anthrax: https://youtu.be/vVD5QtVmC8s Virus Smallest (20 – 400 nm) Single or double-stranded nucleic acids surrounded by a protein coat Requires a host to reproduce using host cell machinery Specific to target cells Prion Mutated cell protein with abnormal structure Cause neurodegenrative diseases No cu