QOD

1
QOD

• How did the first cells on Earth arise?

2
Chapter 14

• Section 1 Biogenesis

3
Theories of Lifes Beginnings

• Spontaneous generation
• Biogenesis

4
Redis Experiment

• Hypothesis
• Controlled experiment
• Results
• Conclusion

5
Other Scientists

• Anton von Leeuwenhoek
• Needham
• Lazzaro Spallanzani
• Louis Pastuer

6
Spallanzanis Experiment
Section 1 Biogenesis
Chapter 14
7
Pasteurs Experiment
Section 1 Biogenesis
Chapter 14
8
Chapter 14

• Section 2 Earths History

9
Formation of Earth

• Earths formation
• Primordial soup
• Earths age
• Radiometric/Radioactive dating
• Radioactive isotopes
• Radioactive decay
• Half-life
• See table 14.1

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Radioactive Decay
Section 2 Earths History
Chapter 14
11
First Organic Compounds

• Alexander Oparin
• Earths early atmosphere
• Miller and Ureys Experiment
• More recent hypothesis

12
Miller-Urey Experiment
Section 2 Earths History
Chapter 14
13
From Molecules to Cell-Like Structures

• Sidney Fox
• Microspheres
• Coacervates

14
Chapter 14

• Section 3 The First Life-Forms

15
QOD

• What is endocytosis? How does it explain the
  origins of eukaryotes? Evidence?

16
Closer Look at DNA and RNA

• Old DNA ? RNA ? Proteins
• New RNA may have more functions
• Many different shapes
• Shapes determined by hydrogen bonding between
  nucleotides
• Behave like proteins?

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Roles of RNA

• Ribozyme Thomas Cech
• Action
• Self-replicate
• Beginning of life?
• Self-replicate
• Heredity
• Evolve by natural selection?

18
Steps Producing Protocells
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19
The First Prokaryotes

• No oxygen in atmosphere
• First cells heterotrophic prokaryotes
• Autotrophs soon after
• Archaebacteria link to first cells
• Anaerobic
• Autotrophs
• Chemosynthesis

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• Cyanobacteria link to first photosynthetic
  prokaryotes
• Oxygen initially damaging
• Evolution of photoautotrophs
• 3.5-3.8 billion years ago
• Ozone

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First Eukaryotes

• Endosymbiosis Figure 14-11
• Supporting evidence
• Double membraned organelle
• Contain own DNA circular
• Contain own ribosomoes similar to prokaryotes
• Reproduce on own binary fission

22
Endosymbiosis Hypothesis
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