Microbiology, Immunity and Forensics
Microbiology, Immunity and Forensics — Edexcel International A-Level Biology (Unit 4, IA2). Covers culturing microorganisms and measuring growth, bacterial growth curves, bacteria vs viruses (Ebola, TMV, HIV, lambda phage), pathogens and infection routes (TB, HIV), non-specific and specific immune responses (B and T cells), immunity types, evolutionary arms race, antibiotics and resistance, microbes in decomposition, PCR and gel electrophoresis, DNA profiling, and forensic biology (time of death). Includes Core Practicals 13 and 14.
Culturing Microorganisms and Measuring GrowthSign up
understand the principles and techniques involved in culturing microorganisms using aseptic technique · understand methods of measuring microbial growth: cell counts, dilution plating, mass and optical methods (turbidity) · understand the phases of a bacterial growth curve (lag, exponential, stationary, death); calculate exponential growth-rate constants · CORE PRACTICAL 13: investigate the rate of growth of microorganisms in a liquid culture, with safe and ethical use of organisms
Bacteria vs Viruses; Lytic vs Latent CyclesSign up
compare bacteria and viruses (nucleic acid, capsid structure, envelope) with reference to Ebola virus, tobacco mosaic virus, human immunodeficiency virus, and lambda phage · understand the terms lytic and latency
Pathogens, Infection Routes and BarriersSign up
understand how Mycobacterium tuberculosis and human immunodeficiency virus infect human cells, causing symptoms that may result in death · know the major routes pathogens may take when entering the body · understand the role of physical/chemical barriers protecting the body from infection: skin, stomach acid, gut and skin flora
Non-Specific Immune ResponseSign up
understand the non-specific responses to infection: inflammation, lysozyme action, interferon and phagocytosis
Specific Immunity: B Cells and T CellsSign up
understand the roles of antigens and antibodies in the body's immune response, including plasma cells, macrophages and antigen-presenting cells · understand the differences between B cells (B memory and B effector) and T cells (T helper, T killer, T memory) in the host's immune response
Immunity Types, Evolutionary Arms Race and Antibiotic ResistanceSign up
understand how individuals develop immunity (natural, artificial, active and passive) · understand how the evolutionary arms race between pathogens and hosts is supported by pathogen evasion mechanisms · understand the difference between bacteriostatic and bactericidal antibiotics · CORE PRACTICAL 14: investigate the effect of different antibiotics on bacteria · know how understanding the contributory causes of hospital-acquired infections has led to codes of practice on antibiotic prescription and infection control
Microbes in Decomposition and the Carbon CycleSign up
know the role of microorganisms in the decomposition of organic matter and the recycling of carbon
Gene Technology: PCR, Gel Electrophoresis and DNA ProfilingSign up
know how DNA can be amplified using the polymerase chain reaction (PCR) · know how gel electrophoresis separates DNA fragments of different length · understand how DNA profiling is used for identification and determining genetic relationships between organisms (plants and animals)
Forensic Biology: Determining Time of DeathSign up
understand how to determine the time of death of a mammal by examining the extent of decomposition, the stage of succession, forensic entomology, body temperature and degree of muscle contraction