Transcript APCellOrganelles13

Organization and Function within
the Cell
AP Big Ideas:
#1—Evolution of Eukaryotic Cells
#2—Cellular Organization and Structure
Before there were cells…
Early Cells
• Evidence for heterotrophic hypothesis:
– We have a single method of fermentation:
glycolysis
– Enzymes in glycoloysis are highly conserved;
suggests the ancestral organism needed to break
down materials it got from its environment:
Protobionts
• http://www.youtube.com/watch?v=GOTke2eJ
5K8
• Rock record shows CO2 concentration in the
atomosphere from early fermentation.
Once there was CO2…
• Cells use the CO2 and
sun’s energy to produce
organic compounds
(photosynthesis)
• This produced O2:
– First oxygen produced:
iron + oxygen = iron
oxides
– About 500 m.y. l. free O2
existed.
• Aerobic bacteria evolved
to use O2 for
respiration=more
efficient.
Once there was oxygen…
• Eukaroytic cells
formed…
• Multicellularity
evolved…
• Sexual reproduction
evolved…
• “Explosion” of
multicellular life in the
last 1000 million
years!(CalledPrecambrian)
3 Main Eras in Multicellular Time
• Paleozoic: Diversity in the ocean (500-250
mya)
• Mesozoic: Diversity on Land: Large reptiles;
mammals small (250-65 mya)
• Cenozoic: Age of flowering plants and
mammals (65 mya – present)
• Each era ended with a Mass Extinction
Endosymbiosis—Describe the theory
in words
A theory needs evidence…
• mtDNA and cpDNA
• Ribosomes and
protein synthesis
• Size/Structure
• Double membranes
• Binary Fission
Why is the prevailing hypothesis
that photosynthesis evolved once?
• Look at the principle of parsimony within the
protist kingdom.
Endomembrane System
Exocytosis
• Production and Secretion of an “exogeneous”
protein
– Identify and sequence the organelles involved in
protein synthesis and secretion
What about an “endogenous” protein?
Examples
• Cell cycle proteins…endogenous
• Hormones…exogenous
What are steriod hormones? Where are they
produced?
Endocytosis
• What organelles are involved?
• Lysosome, vacuole, cell membrane,
microfilaments
What types of cells
do this?
• Amoeba, etc. for
food
• Phagocytic white
blood cells