Topic 11: Origin of Eukaryotes Flashcards
5 Ways Eukaryotes differ from Prokaryotes
- Nucleus and Linear Chromosomes
- Membrane Bound Organelles
- Much Larger
- Possess a Cytoskeleton
- Sexual Reproduction
Sexual Reproduction in Euk.
Undergoes meiosis and fertilization to promotes genetic diversity.
Endosymbiosis
One organism lives inside another organisms cell or tissues, typically mutualistic.
Endosymbiotic Theory
Proposes that mitochondria (proteo) and chloroplasts (cyano) were once small prok. residing in host cells.
What is the main take away from the Serial Endosymbiosis Steps?
The heterotrophic eukaryotes followed by photosynthetic eukaryotes.
What are the three hypothetical steps of Serial Endosymbiosis?
1) Infolding’s of the prok. membrane create the Er and Nuclear envelope
2) Endosymbiosis (of a-proteobacteria) created the mitochondria
3) Another endosymbiont ( a cyanobacteria) became the chloroplast
Primary Endosymbiosis
Prok. cells are engulfed as endosymbionts by either prok. or euk. cells
Secondary Endosymbiosis
euk. cells themselves become endosymbionts, being taken up by euk. cells
Evidence of Endosymbiont Theory
Structural similarities; double membrane, circular DNA, size. Both replicate independently.
Advantages of Multicellularity
Cell Specialization
Increased Size and Complexity
Extended Life Span
Predator Avoidance
Three Domains of Life?
Bacteria, Archaea, Eukarya
Origin of Eukaryotes
Based on significant genetic exchange between domains through horizontal gene transfer.
Protists
An informal term for a diverse group of mostly unicellular eukaryotes.
Protist Diversity
Structural, function, and nutritional diversity as a result of significant endosymbiosis.
Mixotrophs
Able to switch between photoautotrophy and chemoheterotrophy
