Bacterial Reproduction and Uses The two main mechanisms

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

Mechanisms of disease Pathogens can cause disease in two main ways: damaging cells – for example, malarial parasites cause disease symptoms by bursting red blood cells. l producing toxins – exotoxins are secreted by a living, normal pathogen, whereas endotoxins are released when the pathogen is damaged. l 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 • Soluble proteins (produced and substance that makes up the released into the body by outer layer of Gram –ve bacteria) • Rarely fatal – may cause symptoms such as fever, vomiting, diarrhoea • 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 E. coli and salmonella • 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=6 xxd 63 o 7 Usg • 25 most deadly diseases in human history http: //www. youtube. com/watch? v=v. Qb 8 ILpdf. NE • 10 deadliest diseases in human history http: //www. youtube. com/watch? v=ou 7 LQOoo. D_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 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)