Evolution And Structure Of Eukaryotic Cells

Question 1

What is a phylogenetic tree used for

Answer 1

Shows evolutionary history of organisms

Question 2

What are the 3 domains

Answer 2

Archaea , bacteria , eukaryota

First 2 are prokaryotes

Question 3

What is the phylogenetic marker used to track history

Answer 3

Small subunit rrna (SSU rRNA)

Question 4

Can phylogenetic history be inferred from nucleotides/amino acid sequences?

Answer 4

Yes but SSU rRNA is better

Question 5

Why is using rRNA as a phylogenetic marker ideal

Answer 5

All cells have ribosomes

Question 6

How did the first eukarya differ from the rest

Answer 6

They had no mitochondria

Question 7

What is the process called in which a eukaryotic cell developed (Archeoza hypothesis)

Answer 7

Eukaryogenesis

Question 8

Explain phase 1 of the archaezoa hypothesis (endomembranes from endogenous origin)

Answer 8

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

Question 9

Explain the phase 2 of archaezoa hypothesis : endomembranes from exogenous origins

Answer 9

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

Question 10

What type of bacteria was engulfed (endosymbiosis) by an ancestor cell to produce mitochondria

Answer 10

Proteobacterium (aerobic)

Question 11

Why is it that the ancestor cell did engulf the proteobacterium?

Answer 11

Because it was anaerobic and the bacterium was aerobic

Question 12

Why was the archaezoa hypothesis proven wrong

Answer 12

Archaezoa found to have mitochondria in organelles called mitosomes

They also were found to carry genes for mitochondria in their genomes

Question 13

What is the ‘homogenoes’ organelle to mitochondria found on archaezoa

Answer 13

Mitosomes

Question 14

Explain how chloroplasts developed in early eukaryotic cells

Answer 14

Endosymbiosis of photosynthesising bacteria in an early cell

This then became chloroplasts in eukaryotes with own genome (rRNA and genes)

Question 15

What is phagocytosis

Answer 15

A cell engulfing another cell

Either the macrophages engulfing bacteria

Or heterotrophs can engulf other organisms for energy

Question 16

What is the closest ancestor to eukaryotes in the newest tree of life

Answer 16

Asgard

Question 17

What is the function of an endosome

Answer 17

Sorts intercellular material (endocytosed)

Question 18

What is function of a peroxisome

Answer 18

Oxidation of toxic molecules

Question 19

Function of lysosomes

Answer 19

Intercellular degradation (digestive enzymes)

Question 20

What is the name of cytoplasm proper

Answer 20

Cytosol

Question 21

2 functions of mitochondria

Answer 21

Oxidative phosphorylation

FeS cluster biosynthesis

Question 22

What kind of bacteria was endocytosed to produce mitochondria and chloroplasts

Answer 22

Mitochondria - proteo bacterium (aerobic)

Chloroplasts- Cyanobacteria (photosynthesising)