Bacteria Chapter 18.2 p. 484

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BacteriaChapter 18.2p. 484
http//ccl.northwestern.edu/netlogo/models/communi
ty/run.cgi?Bacteria.711.524.0
http//www.cellsalive.com/howbig.htm
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2 Kingdoms (both prokaryotic)

• 1. Archaebacteria
• Extreme environments
• 2. Eubacteria
• Normal environments

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Important Bacterial Diseases
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Importance of Bacteria
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Make antibiotics
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Recycle Nutrients
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Help Digest Food
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Nitrogen Fixation
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Bacterial Shapes
ROD SPIRAL SPHERE
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Bacteria can be

• 1.Heterotrophs
• parasites
• saprophytes
• Feed on dead organisms or organic waste
• 2. Photosynthetic Autotrophs
• 3. Chemosynthetic
• Break down and release energy of inorganic
  compounds containing sulfur and nitrogen

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In favorable conditions bacteria can reproduce
very quickly. Some bacteria can reproduce every
20 minutes, producing an enormous number of
bacteria quickly. If bacteria always reproduced
this fast, they would cover the surface of the
earth within a few weeks. Look at the data below
and graph.
Time (Minutes) Bacteria Cells
20 2
40 4
60 8
80 16
100 32
120 64
140 128
160 256
180 512
200 1,024
220 2,048
240 4,096
260 8,192
280 16,384
300 32,768
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Importance of Bacteria

• Nitrogen fixation
• Recycling of nutrients
• Foods and medicine
• Digestion of food

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Identifying Bacteria

• Gram Staining (page 489)
• Stain reflects a basic difference in the
  composition of cell wall
• Gram Positive
• Purple
• Gram Negative
• Pink

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Shape of bacteria

• Page 489 figure 18.12
• Spheres
• Rods
• Spirals

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How do bacteria reproduce?

• Not by mitosis or meiosis
• Binary Fission or
• Conjugation

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Binary Fission (p. 489)

• Asexual
• Chromosomes are copied
• Chromosomes attach to cell membrane
• Cell grows
• Chromosomes move to opposite sides
• Partition forms
• Two new cells

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Conjugation (p. 490)

• Sexual Reproduction
• One bacterium transfers all or part of its
  chromosome to another cell through or on pili
  that connects the two cells