origin of eukaryotic cells - biology for lifeeukaryotic cell eukaryotic cell with mitochondrion...
TRANSCRIPT
![Page 1: Origin of Eukaryotic Cells - BIOLOGY FOR LIFEeukaryotic cell Eukaryotic cell with mitochondrion internal membrane system aerobic bacterium mitochondrion Endosymbiosis Early eukaryotic](https://reader030.vdocuments.mx/reader030/viewer/2022040107/5e7c199e3901b6286307dc3a/html5/thumbnails/1.jpg)
Origin of Eukaryotic Cells
![Page 2: Origin of Eukaryotic Cells - BIOLOGY FOR LIFEeukaryotic cell Eukaryotic cell with mitochondrion internal membrane system aerobic bacterium mitochondrion Endosymbiosis Early eukaryotic](https://reader030.vdocuments.mx/reader030/viewer/2022040107/5e7c199e3901b6286307dc3a/html5/thumbnails/2.jpg)
AP Biology
Earth is 4.6 byo
Life originated
3.5–4.0 bya
Prokaryotes
dominated earth
for about 1by
![Page 3: Origin of Eukaryotic Cells - BIOLOGY FOR LIFEeukaryotic cell Eukaryotic cell with mitochondrion internal membrane system aerobic bacterium mitochondrion Endosymbiosis Early eukaryotic](https://reader030.vdocuments.mx/reader030/viewer/2022040107/5e7c199e3901b6286307dc3a/html5/thumbnails/3.jpg)
Cyanobacteria A type of prokaryote
with much infolding
of the cell membrane
Capable of
performing
photosynthesis,
which releases
oxygen into the
atmosphere
Cyanobacterium heterocyst
![Page 4: Origin of Eukaryotic Cells - BIOLOGY FOR LIFEeukaryotic cell Eukaryotic cell with mitochondrion internal membrane system aerobic bacterium mitochondrion Endosymbiosis Early eukaryotic](https://reader030.vdocuments.mx/reader030/viewer/2022040107/5e7c199e3901b6286307dc3a/html5/thumbnails/4.jpg)
Oxygen atmosphere Oxygen begins to accumulate 2.7 bya
evidence in banded iron in rocks (rusting)
makes aerobic respiration possible
![Page 5: Origin of Eukaryotic Cells - BIOLOGY FOR LIFEeukaryotic cell Eukaryotic cell with mitochondrion internal membrane system aerobic bacterium mitochondrion Endosymbiosis Early eukaryotic](https://reader030.vdocuments.mx/reader030/viewer/2022040107/5e7c199e3901b6286307dc3a/html5/thumbnails/5.jpg)
nearly all are aerobic,
they depend on free oxygen to carry out their metabolic processes
Accordingly, they could not have evolved before at least some free oxygen was present in the atmosphere
Eukaryotes
![Page 6: Origin of Eukaryotic Cells - BIOLOGY FOR LIFEeukaryotic cell Eukaryotic cell with mitochondrion internal membrane system aerobic bacterium mitochondrion Endosymbiosis Early eukaryotic](https://reader030.vdocuments.mx/reader030/viewer/2022040107/5e7c199e3901b6286307dc3a/html5/thumbnails/6.jpg)
![Page 7: Origin of Eukaryotic Cells - BIOLOGY FOR LIFEeukaryotic cell Eukaryotic cell with mitochondrion internal membrane system aerobic bacterium mitochondrion Endosymbiosis Early eukaryotic](https://reader030.vdocuments.mx/reader030/viewer/2022040107/5e7c199e3901b6286307dc3a/html5/thumbnails/7.jpg)
More Recent Fossil Bacteria and Eukaryotes
1 billion yrs old rocks
prokaryotes
eukaryotic cells
![Page 8: Origin of Eukaryotic Cells - BIOLOGY FOR LIFEeukaryotic cell Eukaryotic cell with mitochondrion internal membrane system aerobic bacterium mitochondrion Endosymbiosis Early eukaryotic](https://reader030.vdocuments.mx/reader030/viewer/2022040107/5e7c199e3901b6286307dc3a/html5/thumbnails/8.jpg)
Two processes are thought to have led
to the origin of eukaryotes….
1. Infoldings of the
prokaryotic cell membrane
2. Endosymbiosis
![Page 9: Origin of Eukaryotic Cells - BIOLOGY FOR LIFEeukaryotic cell Eukaryotic cell with mitochondrion internal membrane system aerobic bacterium mitochondrion Endosymbiosis Early eukaryotic](https://reader030.vdocuments.mx/reader030/viewer/2022040107/5e7c199e3901b6286307dc3a/html5/thumbnails/9.jpg)
Development of internal membranes create internal micro-
environments
advantage = increase efficiency
natural selection!
infolding of the plasma membrane
DNA
cell wall
plasma membrane
Prokaryotic cell
Prokaryotic ancestor of eukaryotic
cells
Eukaryotic cell
endoplasmic reticulum (ER)
nuclear envelope
nucleus
plasma membrane
~2 bya
![Page 10: Origin of Eukaryotic Cells - BIOLOGY FOR LIFEeukaryotic cell Eukaryotic cell with mitochondrion internal membrane system aerobic bacterium mitochondrion Endosymbiosis Early eukaryotic](https://reader030.vdocuments.mx/reader030/viewer/2022040107/5e7c199e3901b6286307dc3a/html5/thumbnails/10.jpg)
Endosymbiosis
Ancestral eukaryotic cell
Eukaryotic cell with mitochondrion
internal membrane
system aerobic bacterium mitochondrion
Endosymbiosis
Early eukaryotic cells engulfed aerobic bacteria
but did not digest them
Led to the origin of mitochondria
Mutually beneficial relationship
natural selection!
![Page 11: Origin of Eukaryotic Cells - BIOLOGY FOR LIFEeukaryotic cell Eukaryotic cell with mitochondrion internal membrane system aerobic bacterium mitochondrion Endosymbiosis Early eukaryotic](https://reader030.vdocuments.mx/reader030/viewer/2022040107/5e7c199e3901b6286307dc3a/html5/thumbnails/11.jpg)
mitochondrion
chloroplast
Eukaryotic cell with
chloroplast & mitochondrion
Endosymbiosis
Endosymbiosis
Early eukaryotic cells engulfed
photosynthetic bacteria
but did not digest them
Led to origin of chloroplasts
mutually beneficial relationship
natural selection!
Eukaryotic cell with
mitochondrion
![Page 12: Origin of Eukaryotic Cells - BIOLOGY FOR LIFEeukaryotic cell Eukaryotic cell with mitochondrion internal membrane system aerobic bacterium mitochondrion Endosymbiosis Early eukaryotic](https://reader030.vdocuments.mx/reader030/viewer/2022040107/5e7c199e3901b6286307dc3a/html5/thumbnails/12.jpg)
In this relationship one symbiont lived within the other, which is a special type of symbiosis called endosymbiosis
in some cases of a symbiotic relationship, one symbiont cannot live independently of the other
This may have been the case early symbiotic prokaryotes that became increasingly interdependent until the unit could exist only as a whole
Endosymbiosis
![Page 13: Origin of Eukaryotic Cells - BIOLOGY FOR LIFEeukaryotic cell Eukaryotic cell with mitochondrion internal membrane system aerobic bacterium mitochondrion Endosymbiosis Early eukaryotic](https://reader030.vdocuments.mx/reader030/viewer/2022040107/5e7c199e3901b6286307dc3a/html5/thumbnails/13.jpg)
A model of the origin of eukaryotes
![Page 14: Origin of Eukaryotic Cells - BIOLOGY FOR LIFEeukaryotic cell Eukaryotic cell with mitochondrion internal membrane system aerobic bacterium mitochondrion Endosymbiosis Early eukaryotic](https://reader030.vdocuments.mx/reader030/viewer/2022040107/5e7c199e3901b6286307dc3a/html5/thumbnails/14.jpg)
Theory of Endosymbiosis
Lynn Margulis
![Page 15: Origin of Eukaryotic Cells - BIOLOGY FOR LIFEeukaryotic cell Eukaryotic cell with mitochondrion internal membrane system aerobic bacterium mitochondrion Endosymbiosis Early eukaryotic](https://reader030.vdocuments.mx/reader030/viewer/2022040107/5e7c199e3901b6286307dc3a/html5/thumbnails/15.jpg)
Both mitochondria & chloroplasts
Resemble bacterial structure
Are found in membranous envelopes (like a cell membrane)
are the same approximate size as prokaryotes
have 70s ribosomes
Structural Evidence
![Page 16: Origin of Eukaryotic Cells - BIOLOGY FOR LIFEeukaryotic cell Eukaryotic cell with mitochondrion internal membrane system aerobic bacterium mitochondrion Endosymbiosis Early eukaryotic](https://reader030.vdocuments.mx/reader030/viewer/2022040107/5e7c199e3901b6286307dc3a/html5/thumbnails/16.jpg)
Both mitochondria & chloroplasts
have circular naked DNA
DNA shares common sequences with modern prokaryotes
Genetic Evidence
![Page 17: Origin of Eukaryotic Cells - BIOLOGY FOR LIFEeukaryotic cell Eukaryotic cell with mitochondrion internal membrane system aerobic bacterium mitochondrion Endosymbiosis Early eukaryotic](https://reader030.vdocuments.mx/reader030/viewer/2022040107/5e7c199e3901b6286307dc3a/html5/thumbnails/17.jpg)
Both mitochondria & chloroplasts
move freely within the cell
reproduce independently from the cell through binary fission
are inhibited by antibiotics
Functional Evidence
![Page 18: Origin of Eukaryotic Cells - BIOLOGY FOR LIFEeukaryotic cell Eukaryotic cell with mitochondrion internal membrane system aerobic bacterium mitochondrion Endosymbiosis Early eukaryotic](https://reader030.vdocuments.mx/reader030/viewer/2022040107/5e7c199e3901b6286307dc3a/html5/thumbnails/18.jpg)
Where Did
Organelles Come From ?
Membranous infoldings
Nucleus
ER
Golgi
Lysosomes
Vesicles
Endosymbiosis
Mitochondria
Chloroplasts
![Page 19: Origin of Eukaryotic Cells - BIOLOGY FOR LIFEeukaryotic cell Eukaryotic cell with mitochondrion internal membrane system aerobic bacterium mitochondrion Endosymbiosis Early eukaryotic](https://reader030.vdocuments.mx/reader030/viewer/2022040107/5e7c199e3901b6286307dc3a/html5/thumbnails/19.jpg)
Membrane infolding
Endosymbiotic theory