Chapter 28 Flashcards
Protist
the informal name of the group of mostly unicellular eukaryotes
Protists constitute a _________ group, and Protista is no longer a valid _______
polyphyletic; kingdom
T/F: Amitochondriaes are considered the oldest lineage of eukaryotes
False; they were at one time, but they no longer are
Amitochondriates
organisms lacking mitochondria
The four supergroups of eukaryotes
1) Excavata
2) “SAR” clade
3) Archaeplastida
4) Unikonta
Excavata
characterized by its cytoskeleton
Some members of the Excavate supergroup have an __________ groove
“excavated” feeding
Excavata includes…
diplomonads, parabasalids, and euglenozoans
Diplomonads and Parabasalids lack _______, have modified _______, and most live in _______ environments
plastids; mitochondria; anaerobic
Diplomonads
have reduced mitochondria (mitoses); derive energy from anaerobic biochemical pathways; have two equal-sized nuclei and many flagella; often parasites
Parabasalids
Have reduced mitochondria called hyrogenosomes that generate energy anaerobically
the “SAR” clade
a diverse monophyletic supergroup named after its three major clades: Stramenopiles, Alveolates, and Rhizarians
The three major clades of the “SAR” clade
1) Stramenopiles
2) Alveolates
3) Rhizarians
Stramenopiles
includes many important photosynthetic organisms; most have a hairy and a smooth flagellum; includes diatoms, golden algae, and brown algae
Diatoms
unicellular algae with a unique two-part, glass-like wall of silicon dioxide
Diatoms are a major component of __________
phytoplankton
Golden algae
named for their color resulting from their yellow and brown carotenoids; all are photosynthetic and some are mixotrophs
Brown algae
the largest and most complex algae; all are multicellular; most are marine; commonly called seaweed
Alternation of generations
the alternation of multicellular haploid and diploid forms
Heteromorphic generations
generations in a life cycle that are structurally different
Isomorphic generations
generations in a life cycle that look similar
Gametophyte
A haploid, multicellular organism that develops from a haploid spore
Spore
a minute, typically one-celled, reproductive unit capable of giving rise to a new individual without sexual fusion
Alveolata
have membrane enclosed sacs (alveoli) under the plasma membrane
alveolate include…
Dinoflagellates, apicomplexans, and ciliates
Dinoflagellates
have two flagella and each cell is reinforced by cellulose plates
T/F: Toxic “red tides” are caused by dinoflagellate blooms
True
Apicomplexans
parasites of animals
T/F: Apicomplexans can cause serious human diseases
True
Sporozoites
The means by which apicomplexans spread through their hosts
T/F: one end of an apicomplexan, the head, contains a complex of organelles specialized for penetrating host cells and tissues
False; the end is actually called the apex
most __________ have a sexual and asexual stages that require __________ host species for completion
apicomplexans; multiple
The apicomplexan __________ is the parasite that causes malaria
Plasmodium
T/F: Plasmodium only requires humans to complete its life cycle
False; it requires both mosquitoes and humans
Ciliates
A large varied group of protists; named for the cilia which they use to move and feed
Conjugation
When two individuals exchange haploid micronuclei; done in ciliates
Conjugations is a _______ and is separate from reproduction
Sexual
Archaeplastida
The supergroup that includes red algae, green algae, and land plants
Red algae
Red in color due to an accessory pigment called phycoerythrin that masks the green chlorophyll
Red algae are usually _________; the largest are seaweeds
multicellular
T/F: Green algae are the most abundant large algae in coastal waters of the tropics
False; red algae
Green Algae
named for their grass-green chloroplasts
______ are descended from the green algae
Plants
The two main groups of green algae are _________ and _________
Charophytes and chlorophytes
T/F: Chlorophytes are most closely related to land plants
False; Charophytes
The supergroup ________ includes animals, fungi, and some protists
Unikonta
Unikonta includes two clades: the __________ and the ___________
amoebozoans; opisthokonts
T/F: The root of the eukaryotic tree remains controversial
True
Many protists are important ________ that obtain energy from the sun
producers
