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Unit 1, Lecture 4
How many years ago did single-celled eukaryotes arise?
2 billion years ago
How many years ago did multicellular eukaryotes arise?
1.5 billion years ago
In what era did animals colonize land?
In what era did prokaryotes arise?
Protists were defined as the kingdom of_______
First eukaryotes were probably _____
What was Ernest Haeckel known for?
Introduced terms protist phylogeny
What did Ernest Haeckel classify organisms based on?
Their morphological characteristics
Who came up with the first tree of life?
Darwin, “I think”
Definition of a protist
A eukaryote that is neither a fungus, plant or animal
4 properties of protists
1. mostly unicellular
2. mostly microscopic
4. nutritionally diverse
ingest their food
perform photosynthesis to make their food
combination of performing making their own food and ingesting it
Properties of protist example: stentor (ciliate)
Properties of protist example: red alga
What type of protists are algae? How do they get their food?
Plant-like protists, photosynthetic
What type of protists are protozoa? How do they get their food?
Animal-like protists, ingestive
What are the four supergroups of eukaryotes?
Protists are no longer viewed as a ________
What is an endosymbiont?
a cell that lives within a host cell
Mitochondria and plastids were formerly _________
small prokaryotes living within larger host cells
both organisms benefit
one organism benefits, the other is unaffected
one organism benefits at the expense of the host
How to tell which is host and which is symbiont?
host= larger organism
symbiont= smaller organism
Who suffers in parasitism?
the host cell
How did modern day eukaryotes acquire mitochondrion?
Larger eukaryotic cell engulfed aerobic heterotrophic prokaryote and evolved to have mitochondrion in almost every eukaryotic organism
Second type of endosymbiosis led to___________
chloroplasts and plastids
Acquisition of mitochondrion happened in ________, whereas acquisition of plastids/chloroplasts happened in _________
every eukaryotic; only in a limited number of eukaryotes
What is a photosynthetic prokaryote?
Plastids refer to?
chloroplasts and related organelles
evolution of red and green algae
Pigments are _______
substances that absorb light
main photosynthetic pigment
Pigment in green algae
Pigment in red algae/cyanobacteria
Pigment in red algae
Pigment in cyanobacteria
What do accessory pigments do?
broaden the spectrum used for photosynthesis
Red algae are usually found where?
deep within the ocean, which is why they developed ability to absorb blue light
What is the porphyrin ring?
structure in chlorophyll that absorbs light
What does the hydrocarbon tail in chlorophyll do?
zanchors the molecule into membrane of thylakoid
CH(?) in chlorophyll a vs. CH(?) in chlorophyll b
CH3 vs. CHO
Differences in chlorophyll a/b/c/d are made by
one or two substitutions in porphyrin ring
What happens when a chlorophyll molecule is excited?
electron goes into excited state, while it falls back down heat and fluorescence is released