Introduction to Virology Lecture Notes PDF

Lecture 1 Orientation and Introduction BSc III Molecular Virology (MVI3MV1) Department of Virology 2025  Course Handout Please read the course handout, posted on Learn2025 , for detailed information on this course  Resources...

Lecture 1 Orientation and Introduction BSc III Molecular Virology (MVI3MV1) Department of Virology 2025  Course Handout Please read the course handout, posted on Learn2025 , for detailed information on this course  Resources Textbooks: Optional reading material Easy to read: COMPULSORY MATERIAL 1. Virology : an illustrated colour text Author: Stephen N J Korsman Learn2025(https://learn2025.ukzn.ac.za/) Westville Library (3 copies) 579.2 VIR 2. Principles of molecular virology Author: Alan Cann All compulsory reading material Westville Library (1 copy) 579.2 CAN will be posted on Learn2025 Reference books: 3. Principles of virology Course handout Author: S Jane Flint Updated Timetable Westville Library (2 copies ) 616.9101 PRI V. 1 Lectures (PowerPoint Presentations) 4. Fields Virology Mini-quizzes Author: Bernard N Fields; David M Knipe; Announcements Westville Library (2 copies ) 616.9101 FIE Reputable websites e.g. http://www.virology.ws/course/ https://hivbook.com/  Introduction to virology What is a virus? “A virus is a piece of bad news wrapped in protein” Peter Medawar  Introduction to virology A complete, mature, infectious viral particle is called a virion When a virion infects a host cell, it is disassembled Building blocks for new virions are then made by the infected host cell The virus then exits the cell and enters a new cell to start another round of replication Viruses infect all living things Size and scale of viruses Properties of viruses Smaller than bacteria almost all viruses are submicroscopic i.e. can only be visualised by electron microscopy Diameter: 10 – 1000 nm (most 20 – 300 nm) Contain only one type of nucleic acid, either DNA or RNA, but never both. Nucleic acid is surrounded by a protein coat Some have additional lipoprotein envelope. Viruses replicate by “tricking” cells into making multiple copies of viral nucleic acid and protein, which then self- assemble to form new virus particles Properties of viruses Do not have organelles, such as mitochondria and ribosomes Cannot replicate outside living cells Do not undergo binary fission Do not grow Cannot generate their own energy/metabolism Do not move on their own i.e. movement is passive Viruses vs. unicellular microorganisms Property Unicellular Viruses microorganisms Size Microscopic Sub-microscopic i.e. i.e. light microscope electron microscope Grow in non-living media Yes No Binary fission Yes No Contain both RNA and Yes No (only 1) DNA Infectious nucleic acid No Yes Ribosomes Yes No Generate energy Yes No Why study viruses? Almost everyone has had a viral infection (and most of us are chronically infected) Most viral infections are minor However, viruses are a significant cause of morbidity and mortality worldwide Consequences include Severe infections +/- hospitalisation Chronic infections +/- sequelae such as cancer Requirement for long term therapy Death Burden on patients, healthcare system and society Viruses have been a threat to mankind throughout history, and will continue to be, despite advances in medicine.  Ancient evidence of viral infections Ramses V died in 1196 BC 3700 BC – Ruma 1193 BC - Pharaoh Siptah Polio Influenza HIV SARS-CoV-2 Learning Goals Define a virus Define virion List the properties of a virus Differentiate viruses from other micro-organisms Examples of Quiz/exam questions A virus comprises genetic material surrounded by a ___________ Examples of Quiz/exam questions A virus comprises genetic material surrounded by a protein coat Examples of Quiz/exam questions List three properties of a virus Example of Quiz/exam questions List three properties of a virus Contains nucleic acid (either RNA or DNA) Has a protein coat Can only replicate inside a cell Examples of Quiz/exam questions Is the following statement TRUE or FALSE: Most viruses are about the same size as bacteria Examples of Quiz/exam questions Is the following statement TRUE or FALSE Most viruses are about the same size as bacteria FALSE Examples of Quiz/exam questions Which one of these properties describes a virus rather than a unicellular organism Can grow in media without cells Undergoes binary fission May contain infectious nucleic acid Contains both RNA and DNA Examples of Quiz/exam questions Which one of these properties describes a virus rather than a unicellular organism Can grow in media without cells Undergoes binary fission May contain infectious nucleic acid Contains both RNA and DNA Examples of Quiz/exam questions Label the following diagram Examples of Quiz/exam questions Label the following diagram 1 = envelope 2 = protein coat (or capsid) 3 = genome (or nucleic acid or RNA/DNA)