Bacterial Reproduction and Uses The two main mechanisms used by Bacteria for Reproduction How Transformation was investigated. Bacteria as Pathogens and Benefactors Key Terms: Binary Fission, Conjugation, Transformation, Transduction, Endotoxin, Exotoxin.

Binary Fission – Vertical Gene Transfer

Transformation & Transduction Horizontal Gene Transfer

Conjugation - Horizontal Gene Transfer

Conjugation

Mechanisms of Transfer

Boardworks AS Biology Infectious Diseases Mechanisms of disease Boardworks AS Biology Infectious Diseases Pathogens can cause disease in two main ways: damaging cells – for example, malarial parasites cause disease symptoms by bursting red blood cells. producing toxins – exotoxins are secreted by a living, normal pathogen, whereas endotoxins are released when the pathogen is damaged. For example, the symptoms of cholera are caused by an exotoxin secreted by the bacteria Vibrio cholerae. It increases the secretion of chloride ions into the lumen of the intestines, which can lead to severe diarrhoea.

Bacterial Toxins Endotoxins Exotoxins Lipopolysaccharides (this is the substance that makes up the outer layer of Gram –ve bacteria) Rarely fatal – may cause symptoms such as fever, vomiting, diarrhoea Examples include E. coli and salmonella Soluble proteins (produced and released into the body by bacteria) Often very dangerous or even fatal - have a variety of effects such as damage to cell membranes or acting as competitive inhibitors to neurotransmitters Examples include C. botulinum

Beneficial Bacteria In your body bacterial cells out-number your own human body cells by 10:1 !!!!! There are 1014 bacteria in your body !!!! They weigh about 2.2 Kg !!!!

Infectious Diseases Videos Top 10 Infectious Diseases (best one) http://www.youtube.com/watch?v=6xxd63o7Usg 25 most deadly diseases in human history http://www.youtube.com/watch?v=vQb8ILpdfNE 10 deadliest diseases in human history http://www.youtube.com/watch?v=ou7LQOooD_0

Activities 1) Summarise the role of Beneficial bacteria in: a) the gut b) Ecosystems i) as part of the Nitrogen Cycle (Hint: What do Nitrifying, Decomposing and Nitrogen-fixing bacteria do?) ii) as part of the Carbon Cycle 2) Use the sheet ‘Invading the Body’ to show how infections can be passed from person to person. 3) Complete ‘Pathogens and Infection’ (You may need to use the additional textbooks or the Internet to research some of the diseases)