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Protist

any eukaryote that is not a plant, animal, or fungus. Most protists are unicellular

Mixotrophs

Combine photosynthesis and heterotrophic nutrition

Secondary Endosymbiosis

A process in eukaruotic evolution in which a heterotrophic eukaryotic cell engulfed a photosynthetic euk. cell, which survived in a symbiotic relationship inside the heterotrophic cell.

Five Supergroups

Excavata, Chromalveolata, Rhizaria, Archaeplastida, Unikonta

Excavata

Groove on one side (some have modified mitochondria)

Chromalveolata

May have originated by sec. endosymbiosis; includes some of the most important photsynthetic organisms on earth.

Rhizaria

Species of amoeba which have pseudopodia (used in movement)

Archaeplastida

include red and green algae

Unikonta

includes amoebas that have lobe- or tube- shaped pseudopodia

Cite 4 examples of structural and functional diversity among protists.

-unicellular, colonial, or multicellular
-photoautotrophs, heterotrophs, and mixotrophs
-produce asexually, sexually, or both
-diverse physical forms and adaptations

Summarize the role of endosymbiosis in eukaryotic evolution

strong evidence shows that eukaryotes acquired mitochondria after an early eukaryote first engulfed and then formed an endosymbiotic association with an alpha proteobacterium. Sililarly, chloroplasts in red and green algae appear to have descended from a photsynthetic cyanobacterium that was engulfed by an ancient hetertrophic eukaryote. SEcondaru endosymbiosis also played an important role: Various protist lineages acquired plastids by engulfing unicellular red or green algae.

Why do some biologists describe the mitochondria of diplomonads and parabasalids as "highly reduced?"

Their mitochondria do not have an electron trasnport chain and so cannot funciton in aerobic respiration.

Alternation of Generations

the alternation of multicellular haploid and diploid forms.

Heteromorphic

the sporophytes and gametophytes are structurally different

Isomorphic

the s-phytes and g-phyts look similar, but differ in chromosome number

Protists that are surrounded by more than two membranes are evidence of:
a. evolution from mitochondria
b.fusion of plastids
c. origin of the plastids from archaea
d. secondary endosymbiosis
e. budding of the plastids from the nuclear envelope

d. secondary endosymbiosis

Biologists suspect that endosymbiosis gave rise to mitochondria before plastids because:

all eukaryotes have mitochondria (or their remnants) whereas many eularyotes do not have plastids

Which group is incorrectly paired with its description:
a. rhizarians- morphologically diverse group define by dna similarities
b. diatoms- important producers in aquatic communities
c. red algae- acquired plastids by secondary endosymbiosis
d. apicomplexans- parasites with intricate life cycles
e. diplomonads- protists with modified mitochondria

red algae did not acquire plastids by secondary endosymbiosis

Which protists are in the same eukaryotic supergroup as land plants?

green and red algae

In life cycles with an alternation of generations, multicellular haploid forms alternate with

multicellular diploid forms.

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