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Bacteria Reproduction and Metabolism

Bacteria Reproduction and Metabolism. Bacteria Take Over!. Under ideal stable conditions, bacteria can multiply at alarming rates…. Within a week, the bacteria would weigh More than the earth …. So… Why don’t bacteria take over the earth?. Conditions for Growth.

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Bacteria Reproduction and Metabolism

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  1. Bacteria Reproduction and Metabolism

  2. Bacteria Take Over! Under ideal stable conditions, bacteria can multiply at alarming rates… Within a week, the bacteria would weigh More than the earth…

  3. So… Why don’t bacteria take over the earth?

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

  5. Endospores • 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

  6. Endospores • Examples: • Bacillus anthracis (anthrax) • 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

  7. Nutrition • 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 • Chemosynthetic

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

  9. Bacteria and 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 aerobes – organisms that grow only in the presence of free oxygen • Facultative anaerobes – organisms that can grow with or without oxygen

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

  11. Reproduction • 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 • Bacteria exchange DNA through the pili structures

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