16.1 Prokaryotic life began on a young earth

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16.1 Prokaryotic life began on a young earth
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I. The Oldest Fossils

• A. Stromatolites- are thin layers of rock that
  contain ancient fossils
• B.Prokaryotes are simple organisms that lack true
  nuclei and many of the organelles found in
  eukaryotes

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II. How Did Life Begin?

• A. The early Earth was able to produce organic
  molecules that are essential to life and this was
  duplicated by Stanley Miller
• B. Millers experiment was able to produce simple
  molecules but experiments show that even more
  complex molecules could be created by duplicating
  the early Earth

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Miller-Urey
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II. How Did Life Begin?

• C. RNA is thought to be the molecule that started
  to store genetic information and direct protein
  synthesis
• D. Experiments have shown that polypeptides can
  come together and form microscopic, fluid-filled
  spheres
• E. All of the experiments support a hypothetical
  four-stage sequence for how life could have
  developed

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RNA
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III. Where Did Life Begin?

• A. It used to be thought that life began in
  shallow water
• B. Deep Sea vents are populated with prokaryotes
  that resemble some of the earliest cells

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Concept 16.2 Diverse prokaryotes populate the
biosphere
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I. Diversity of Prokaryotes

• A. Most bacteria do not cause disease and many
  can be helpful to humans or other organisms
• B. Prokaryotes help cycle nutrients between
  organisms, the soil and the atmosphere
• C. The are two Types of Prokaryotes
• 1. Archaea- which means ancient live in some
  of the most extreme environments on Earth
• 2. Bacteria- differ from archaea in their
  nucleic acids, enzymes and cell wall

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II. Structure and Function of Bacteria

• A. Cell Shape
• 1. Cocci- Spheres
• 2. Bacilli- Rods
• 3. Spirochetes- Spirals
• B. Cell Wall Structure- Gram
• positive (purple) or Gram negative
  (red)
• C. Motility- About half are motile

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III. Reproduction

• A. Rapid Reproduction-Some bacteria can divide
  every 20 minutes
• B. Genetic Reproduction
• 1. Transformation- Bacteria take up DNA from
  the environment and incorporate it
• 2. Conjugation- Two bacterial cells join
  together and transfer genetic material
• 3. Binary fission- makes a duplicate copy
• C. Endospore Formation- Some bacteria form spores
  when environmental conditions become severe

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Binary Fission
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Nutrition

• D. Modes of Nutrition
• 1. Photo- gets energy from
• photosynthesis
• 2. Chemo- gets energy from chemical
• sources
• 3. Autotrophs- obtain carbon atoms
• from CO2
• 4. Heterotrophs- obtain carbon from
• existing organic molecules

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IV. Cyanobacteria and the Oxygen Revolution

• A. Earths early atmosphere very little or no
  free oxygen
• B. Cyanobacteria release oxygen as a byproduct of
  photosynthesis
• C. Nearly all eukaryotes are aerobic and owe
  their evolution to cyanobacteria

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Concept 16.3 Prokaryotes perform essential
functions in the biosphere
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I. Chemical Recycling

• A.Many prokaryotes perform an essential function
  by breaking down organic waste products and dead
  organisms in the environment
• B.Carbon is returned into the atmosphere as
  carbon dioxide, nitrogen is taken from the
  atmosphere and fixed in nitrogen compounds in
  soil and water

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II. Human uses of Prokaryotes

• A. Humans use bacteria to remove pollutants from
  water, air and soil in a process called
  bioremediation
• B. Pseudomonas bacteria has been shown to be able
  to help clean up oil spills
• C. Bacteria are also used to clean up arsenic,
  copper, zinc, lead and mercury. They can also be
  used to make vitamins and antibiotics
• D. Genetic engineering is finding more and more
  uses for bacteria

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Concept 16.4 Some prokaryotes cause disease
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I. How Bacteria Cause Illness

• A. Bacteria and other microorganisms that cause
  disease are called pathogens
• B. Most pathogenic bacteria cause disease by
  producing one of two types of bacterial poisons.
  One type is secreted by the bacterium and the
  other is a component of the bacterias cell wall

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II. Defense Against Bacterial Diseases

• A. The major reason for the decline in bacterial
  diseases is better hygiene and public health
  measures
• B. The human body has built in defenses against
  disease
• C. The other way to defend against bacterial
  diseases is through the use of antibiotics

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Concept 16.5 Viruses Infect Cells by Inserting
Genes
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I. Virus Structure and Reproduction

• A virus is composed of a short piece of DNA
• or RNA surrounded by a protein coat
• B. There are two ways that viruses reproduce
• 1. Lytic Cycle- the virus attaches itself
  to
• the host and injects its DNA
• 2. Lysogenic Cycle- the virus injects its
• DNA into the host and it is
  incorporated
• into the host cells DNA

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II. Viruses and Disease

• A. A virus that causes disease must use the host
  cell to reproduce
• B. Antibiotics do not work on viral illness so
  the bodys immune system must destroy the virus

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III. HIV A Retrovirus

• A. AIDS is the disease which is caused by the HIV
  virus
• B. HIV is a retrovirus which means their genetic
  information is carried in RNA
• C. The RNA is transcribed into DNA with the help
  of the enzyme reverse transcriptase

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IV. Defense Against Viral Disease

• A. Vaccines are deactivated varieties or small
  pieces of pathogen that stimulate the immune
  system to respond to a particular pathogen
• B. The first vaccine was for smallpox it was
  invented in the 1700s by Edward Jenner
• C. Some viruses mutate rapidly and are not
  recognized by the body, such as the flu and HIV