Under ideal stable conditions, bacteria can multiply at alarming rates… min. Bacteria can grow and divide every min. 1,000,000,000 Within 15 hours, a single cell could have multiplied into 1,000,000,000 cells 2000 tons In 24 hrs. the mass of cells would weigh over 2000 tons Within a week, the bacteria would weigh More than the earth More than the earth…

Several environmental factors must be within a bacterium’s optimal range for it to grow and divide o Moisture o Temperature o pH o Nutrition Different species have specific requirements in order to grow and reproduce

When some bacillus bacteria and other types are exposed to extended periods of unfavorable conditions, they are capable of forming endospores Endospores have several layers of hard materials protecting the bacteria’s DNA This allows them to withstand: 20 hours of boiling Freezing Extreme dryness Extreme pressure Poison gas and harsh chemicals

Examples: Examples: Bacillus anthracis (anthrax) Bacillus anthracis (anthrax) Clostridium tetani (tetanus or lockjaw) Clostridium tetani (tetanus or lockjaw) Bacteria that form endospores are of particular interest because they can survive thousands of years and become resistant to antibiotics Bacteria that form endospores are of particular interest because they can survive thousands of years and become resistant to antibiotics

Bacteria are classified into 2 main groups based on how/where they obtain their food: Bacteria are classified into 2 main groups based on how/where they obtain their food: 1. Autotrophs – Are able to make their own food using sunlight or chemicals Photosynthetic Photosynthetic Chemosynthetic Chemosynthetic

2. Heterotrophs – must obtain their food from other sources than themselves Parasitic – feeding on a living host for nutrients Parasitic – feeding on a living host for nutrients Obligate parasites go a step further and require living tissue in order to grow Obligate parasites go a step further and require living tissue in order to grow Saprophytic – feeding on dead organic matter for nutrients Saprophytic – feeding on dead organic matter for nutrients

Louis Pasteur demonstrated that some bacteria can grow without (and are actually inhibited or destroyed by) free oxygen Louis Pasteur demonstrated that some bacteria can grow without (and are actually inhibited or destroyed by) free oxygen Obligate anaerobes – organisms that grow only in the absence of free oxygen Obligate anaerobes – organisms that grow only in the absence of free oxygen Obligate aerobes – organisms that grow only in the presence of free oxygen Obligate aerobes – organisms that grow only in the presence of free oxygen Facultative anaerobes – organisms that can grow with or without oxygen Facultative anaerobes – organisms that can grow with or without oxygen

Binary Fission Binary Fission Asexual Asexual Time Frame: Time Frame: From once/20 minutes to 2-3 days From once/20 minutes to 2-3 days

Conjugation – a process in which bacteria exchange or transfer genetic information Conjugation – a process in which bacteria exchange or transfer genetic information Since there is no meiosis involved and not all genes are transferred it is not considered true sexual reproduction Since there is no meiosis involved and not all genes are transferred it is not considered true sexual reproduction Bacteria exchange DNA through the pili structures Bacteria exchange DNA through the pili structures