Question 27

 

What are the current models for the origin of biological macromolecules, prokaryotic cells, and eukaryotic cells? [Chapters 26, 27, and 28]

 

The Origin of Life (read pages 516-522)

 

1.      The first cells may have originated by chemical evolution on a young Earth.

 

2.      Abiotic synthesis of organic monomers is a testable hypothesis.

 

3.      Laboratory simulations of early-Earth conditions have produced organic polymers.

 

4.      RNA may have been the first genetic material.

 

5.      Protobionts can form by self-assembly.

 

6.      Natural selection could refine protobionts containing hereditary information.

 

7.      Debate about the origin of life abounds.

 

The Major Lineages of Life (read pages 522-523)

 

1.      The five-kingdom classification system reflected increased knowledge of life’s diversity.

 

2.      Arranging the diversity of life into the highest taxa is a work in progess.

 

The Structure, Function, and Reproduction of Prokaryotes (read pages 528-532)

 

  1. Nearly all prokaryotes have a cell wall external to the plasma membrane.

 

  1. Many prokaryotes are motile

 

  1. The cellular and genomic organization of prokaryotes is fundamentally different from eukaryotes.

 

  1. Prokaryotes adapt rapidly.

 

Nutritional and Metabolic Diversity of Prokaryotes (read pages 532-535)

 

  1. Prokaryotes can be grouped into four categories based upon how they obtain energy and carbon.

 

  1. Photosynthesis evolved early in prokaryote history.

 

The Ecological Impact of Prokaryotes (read pages 540-542)

 

  1. Prokaryotes recycle chemical elements in ecosystems.

 

  1. Many prokaryotes are symbiotic.

 

  1. Pathogenic prokaryotes cause many human diseases.

 

  1. Humans use prokaryotes in research and technology.

 

Introduction to the Protista (read pages 546 to 548)

 

  1. Systematists have split Protista into many Kingdoms.

 

  1. Protists are the most diverse of all eukaryotes.

 

The Origin and Diversity of Eukaryotes (read pages 548-554)

 

  1. Endomembranes contributed to larger and more complex cells.

 

  1. Mitochondria and plastids evolved from endosymbiotic bacteria.

 

  1. The eukaryote cell is a chimera of prokaryote ancestors.

 

  1. Secondary endosymbiosis increased the diversity of algae.

 

  1. Research is changing ideas about the relationships of prokaryotes and eukaryotes.

 

  1. The origin of eukaryotes catalyzed a second great wave of diversification.

 

 

 

 

 

 

 

John C. Murphy

           Science

Phone:  (815) 436-3200, ext. 2120

 

jmurphy@learningcommunity202.org

 


 

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