Lecture 9 - First Eukaryotes

Question 1

oldest unicellular and multicellular organisms

Answer 1

Oldest UNIcellular

• > 2.0 billion yo

Oldest MULTIcellular

• > 1.2 billion yo
• > likely red alga, found in the Canadian Arctic
• > cellular differentiation and reproduction evident

Question 2

List the 4 main eukaryote “supergroups”

Answer 2

1. Excavata
2. “sar” dade
3. Archaeplastida
4. Unikonta

Question 3

Are protistis monophyletic

Answer 3

NO

Question 4

Key innovation of early eukaryotic evolution

Answer 4

1. Cytoskeleten
2. Compartments
3. Mitosis, diploidy, meiosis and sex

Question 5

which processes use the cytoskeleton for internal cellular movement

Answer 5

1. Cytoplasmic streaming
2. Mitosis and meisois

Question 6

which processes/structures use the cytoskeleton for external cellular movement

Answer 6

1. Flagella
2. Pseudopods (amoeboid motion)
3. Phagotrophy

Question 7

compartmentalization

Answer 7

• > allows cells to maintain separate internal environments

Question 8

primary endosymbiosis hypothesis

Answer 8

• > early eukaryotes engulfed aerobic prokartyotes (use O₂/ mitochondria) and photosynthetic prokaryotes (w/chloroplasts) and established a symbiotic relationship rather then digesting prokaryotic the organism

Question 9

Evidence of primary endosymbiosis hypothesis in terms of the mitochondria

Answer 9

1. Two membranes
   - > outer from host food vacuole
   - > inner from bacterial endosymbiont
2. Chromosomes are circular
   - > mitochondria DNA is closely related to alphaproteobacteria DNA

Question 10

Evidence of primary endosymbiosis hypothesis in terms of the chloroplast

Answer 10

1. Two membranes
   - > outer from host food vacuole
   - > inner from bacterial endosymbiont
2. Chromosomes are circular
3. DNA is closely related to cyanobacterial DNA

Question 11

Endogenous origin vs Endosymbiotic Origin of cells

Answer 11

Endogenous origin

• > Endogenous substances and processes are those that originate from within a system such as an organism, tissue, or cell

Endosymbiotic origin

• > organism/organelle was engulfed and used by cell