Evolution And Structure Of Eukaryotic Cells Flashcards
What is a phylogenetic tree used for
Shows evolutionary history of organisms
What are the 3 domains
Archaea , bacteria , eukaryota
First 2 are prokaryotes
What is the phylogenetic marker used to track history
Small subunit rrna (SSU rRNA)
Can phylogenetic history be inferred from nucleotides/amino acid sequences?
Yes but SSU rRNA is better
Why is using rRNA as a phylogenetic marker ideal
All cells have ribosomes
How did the first eukarya differ from the rest
They had no mitochondria
What is the process called in which a eukaryotic cell developed (Archeoza hypothesis)
Eukaryogenesis
Explain phase 1 of the archaezoa hypothesis (endomembranes from endogenous origin)
An ancient procaryote started off with dna and no nucleus and membrane bound ribosomes
This then later developed by envaginosis of the ancient eukaryotic cell which had endomembranes such as ER, nuclear envelope, cytosol
Explain the phase 2 of archaezoa hypothesis : endomembranes from exogenous origins
An ancestor of a eukaryote cell engulfed a proteobacterium (endosymbiosis) and this then later turned into mitochondria with its own genome - this is the early eukaryotic cell
What type of bacteria was engulfed (endosymbiosis) by an ancestor cell to produce mitochondria
Proteobacterium (aerobic)
Why is it that the ancestor cell did engulf the proteobacterium?
Because it was anaerobic and the bacterium was aerobic
Why was the archaezoa hypothesis proven wrong
Archaezoa found to have mitochondria in organelles called mitosomes
They also were found to carry genes for mitochondria in their genomes
What is the ‘homogenoes’ organelle to mitochondria found on archaezoa
Mitosomes
Explain how chloroplasts developed in early eukaryotic cells
Endosymbiosis of photosynthesising bacteria in an early cell
This then became chloroplasts in eukaryotes with own genome (rRNA and genes)
What is phagocytosis
A cell engulfing another cell
Either the macrophages engulfing bacteria
Or heterotrophs can engulf other organisms for energy
What is the closest ancestor to eukaryotes in the newest tree of life
Asgard
What is the function of an endosome
Sorts intercellular material (endocytosed)
What is function of a peroxisome
Oxidation of toxic molecules
Function of lysosomes
Intercellular degradation (digestive enzymes)
What is the name of cytoplasm proper
Cytosol
2 functions of mitochondria
Oxidative phosphorylation
FeS cluster biosynthesis
What kind of bacteria was endocytosed to produce mitochondria and chloroplasts
Mitochondria - proteo bacterium (aerobic)
Chloroplasts- Cyanobacteria (photosynthesising)
