Transcript Earth`s Early History 10-2

Welcome to Class!
10-2
Complete the following:
 New entry “Early Earth History”
 Review of Biochemistry TEST (spoon)
 Homefun:
 Study for your test is on Monday Oct 5 and Tuesday
Oct 6
Earth’s Early History
Learning Objectives
 Identify some of the hypotheses about early Earth and
the origin of life.
 Discuss the hypothesis that explains the origin of
eukaryotic cells.
The Mysteries of Life’s Origins
The Miller–Urey Experiment
2 A mixture of methane,
ammonia, and hydrogen is
added to the water vapor.
1
Water is heated, and
water vapor forms.
3
The circulating
gases are bombarded
by sparks of electricity.
4 Cold water cools the
chambers, causing
droplets to form.
5
After a week,
liquid is collected,
which contains
amino acids and
other organic
compounds.
RNA First?
Inorganic matter
Simple organic molecules
RNA nucleotides
DNA functions in
information storage
and retrieval.
RNA is able to replicate itself,
synthesize proteins, and
function in information storage.
RNA helps in protein synthesis.
Proteins build cell
structures and
catalyze chemical
reactions.
Life Changes the Atmosphere
Origin of Eukaryotic Cells
Ancient
photosynthetic
bacteria
Ancient
aerobic
bacteria
Nuclear
envelope
forming
Plants and
photosynthetic
unicellular
eukaryotes
Primitive
photosynthetic
eukaryote
Ancient
anaerobic
prokaryote
Mitochondrion
Primitive
aerobic
eukaryote
Animals, fungi, and
nonphotosynthetic
unicellular
eukaryotes
Complexity in Eukaryotes
Eukaryotic Structures
Krebs cycle
Ribosomes
Cilia and
flagella
Nearly all key enzymes
in the Krebs cycle were
borrowed from other
pathways in the cell.
The earliest cells may
have produced
proteins using RNA
alone. This RNA
became the ribosome;
proteins were added
to improve efficiency.
Flagella are assembled
from protein subunits
that serve other
purposes elsewhere in
the cell.