6 Flashcards
Origin of eukaryotes?
*Loss of firm cell wall, increasing surface area:volume ratio
*Cytoskeleton forms from microtubules
*internal membrane with ribosomes
*unfolded membrane enclosed DNA forming the nucleus
*Flagellum formed from microtubules
*endosymbiosis led to mitochondria and chloroplasts.
How long ago did the eukaryotic cell evolve?
2.0 billion years ago
phagocytosis?
when one cell is engulfed by another and usually ingested.
protist?
a group of organisms that are not monophyletic.
The four groups of protists?
*alveolates
*stramenopiles
*excavates
*Ameobozoans
Protists are eukarya that are not?
not animals, fungi, or plants.
Alveolates?
unicellular with sacs (alveoli) beneath cell membrane, secondary endosymbiosis of red algae. They have chloroplasts via secondary endosymbiosis of red algae.
Alveolates: ciliates, paramecium?
about 7000 species covered with cilia. it allows them to move in a substrate. Unicellular
Alveolates: Dinoflagellates?
two flagella, one in equatorial groove, the other longitudinal. They have a chloroplast via tertiary endosymbiosis. They are also endosymbionts of coral. A few are freshwater, many abundant as marine plankton. They also cause red tides
Dinoflagellates release what in response to temperature?
neurotoxin, and then the coral expel them. Corals can no longer obtain energy from dinoflagellates.
Red tides consist primarily of?
Dinoflagellates lacking oxygen.
Alveolates: Plasmodium - malaria?
these intracellular parasites (where chloroplast is vestigial) contain a complex of proteins at the apical prominence attach to and penetrate the host cell.
Stramenopiles?
two unequal flagella, one of which has tubular hairs. Many have lost their flagella. Chloroplasts via secondary endosymbiosis of red algae. They are the only group with some multicellular taxa.
Stramenopiles: brown algae?
multicellular, some are very large. Some are known as kelp and form the kelp forests.
Stramenopiles: diatoms?
unicellular, have secondary lost their double flagella. They deposit silica in their membranes, forming beautiful shells. Almost all are marine. They fix about 20% of earth carbon.
Excavates?
characterized by having reduced or lost mitochondria.
Excavates: Giardia?
A common unicellular intestinal parasite.
Excavates: Euglenids?
have mitochondria with one large flagellum, and acquired a chloroplast from secondary endosymbiosis of green algae.
Excavates: Trypanosoma?
single celled with a single and large mitochondria. Some are free living while others are parasitic.
Diseases caused by Trypanosomes? 3*
*Sleeping sickness
*Chagas disease
*Leischmaniasis
Amoebozoans?
Lobe-shaped pseudopods, lobe shaped extensions that they use to move by cytoplasmic streaming.
Amoebozoans: Slime molds?
Unicellular but multinucleic
Amoebozoans: Amoeba?
unicellular organisms with the ability to change its shape by extending and retracting pseudopods.
pseudopods?
A temporary arm-like projection of a eukaryotic cell emerged in the direction of movement.
What evidence do we have that mitochondria are derived from the endosymbiosis of a proteobacterium?
They have two membranes, one is the original proteobacterium membrane. They also have their own DNA, coiled in a similar way to proteobacteria.
Evidence that chloroplasts derived from the endosymbiosis of cyanobacteria?
They have two membranes, one from cyanobacterium, and they have their own DNA, whose chromosomes are shaped similarly to cyanobacteria.
How many times did primary endosymbiosis of cyanobacterium happen?
once
Secondary endosymbiosis of green algae gave rise to?
Euglenid (one protist group, NOT plants) chloroplasts.
All plants have chloroplasts that derived in what type of endosymbiosis?
primary endosymbiosis.
Secondary endosymbiosis of Red Algae gave rise to?
stramenopile and alveolate chloroplasts.
Tertiary endosymbiosis?
A eukaryotic cell with no chloroplasts engulfs a eukaryote with chloroplasts from secondary endosymbiosis of red algae.
Every time we have endosymbiosis, what gets added?
More membranes get added.
A summary of all those different types of endosymbiosis? 4*
*Primary endosymbiosis of cyanobacterium: common ancestor of Glaucophytes, Red Algae, Green Algae, and Land plants.
*Secondary endosymbiosis of green algae: euglenids
*secondary endosymbiosis of red algae: stramenopiles and Alveolates
*Tertiary endosymbiosis of a eukaryote that has chloroplasts from endosymbiosis of red algae: dinoflagellates (also endosymbionts of coral)
Did amoebozoans undergo endosymbiosis?
no
