IAL Biology Unit 4

Topic 6 – Microbiology, Immunity and Forensics

6.1 Culturing Microorganisms

Understand the principles and techniques involved in culturing microorganisms , using aseptic technique

6.2 Measuring Growth of Microorganisms

Understand the different methods of measuring the growth of microorganisms , as illustrated by cell counts , dilution plating , mass and optical methods (turbidity)

6.3 Bacterial Growth Curve

Understand the different phases of a bacterial growth curve ( lag phase , exponential phase , stationary phase and death phase ) and be able to calculate exponential growth rate constants

6.4 CORE PRACTICAL 13

Investigate the rate of growth of microorganisms in a liquid culture, taking into account the safe and ethical use of organisms.

6.5 Structure of Bacteria and Viruses

(i) Be able to compare the structure of bacteria and viruses ( nucleic acid , capsid structure and envelope ) with reference to Ebola virus , tobacco mosaic virus (TMV) , human immunodeficiency virus (HIV) and lambda phage (λ phage)

(ii) Understand what is meant by the terms lytic and latency

6.6 Infection by Mycobacterium tuberculosis and HIV

Understand how Mycobacterium tuberculosis and human immunodeficiency virus (HIV) infect human cells, causing symptoms that may result in death

6.7 Pathogen Entry and Barriers to Infection

(i) Know the major routes pathogens may take when entering the body

(ii) Understand the role of barriers in protecting the body from infection, including skin , stomach acid , and gut and skin flora

6.8 Non-Specific Responses to Infection

Understand the non-specific responses of the body to infection, including inflammation , lysozyme action , interferon and phagocytosis

6.9 Antigens and Antibodies

Understand the roles of antigens and antibodies in the body’s immune response including the involvement of plasma cells , macrophages and antigen-presenting cells

6.10 Roles of B Cells and T Cells

Understand the differences between the roles of B cells ( B memory and B effector cells ), and T cells ( T helper , T killer and T memory cells ) in the host’s immune response

6.11 Development of Immunity

Understand how individuals may develop immunity ( natural , artificial , active and passive )

6.12 Evolutionary Race between Pathogens and Hosts

Understand how the theory of an ‘ evolutionary race ’ between pathogens and their hosts is supported by evasion mechanisms shown by pathogens

6.13 Bacteriostatic and Bactericidal Antibiotics

Understand the difference between bacteriostatic and bactericidal antibiotics

6.14 CORE PRACTICAL 14

Investigate the effect of different antibiotics on bacteria

6.15 Hospital-Acquired Infections

Know how an understanding of the contributory causes of hospital-acquired infections has led to codes of practice regarding antibiotic prescription and hospital practice that relate to infection prevention and control

6.16 Role of Microorganisms in Decomposition

Know the role of microorganisms in the decomposition of organic matter and the recycling of carbon

6.17 Polymerase Chain Reaction (PCR)

Know how DNA can be amplified using the polymerase chain reaction (PCR)

6.18 Gel Electrophoresis

Know how gel electrophoresis can be used to separate DNA fragments of different lengths

6.19 DNA Profiling

Understand how DNA profiling is used for identification and determining genetic relationships between organisms (plants and animals)

6.20 Determining Time of Death

Understand how to determine the time of death of a mammal by examining the extent of decomposition , stage of succession , forensic entomology , body temperature and degree of muscle contraction