ch 33: protists
What is our current understanding of the phylogeny of organisms that possess chloroplasts?
All chloroplasts likely evolved from a single line of cyanobacteria, however, photosynthetic eukaryotes are not monophyletic.
Which of the following is an advantage of multicellularity?
It fostered the specialization of cells.
Protist reproduction is ____.
asexual and sexual (depends on species)
Protists typically reproduce ____ although some have an obligate _____ reproductive phase.
asexually, sexual
Long, thin pseudopods supported by axial rods of microtubules are called
axopodia
the ____ of protists are long, thin protrusions supported by axial rods of microtubules.
axopodia
The evolution of multicellularity allowed ____.
cells to become specialized
A ___ organism is made of cells that are permanently associated, but have little or no integration of cellular activities.
colonial
Even though chloroplasts of different algae are not monophyletic, it is thought that all chloroplasts derived from a single line of
cyanobacteria
A thick-walled unicellular life stage produced by many protists that can remain dormant during stressful periods is known as a(n)
cyst.
Bacteria that live within other cells and perform specific functions for their host cells are called ____.
endosymbiotic bacteria
Protists are alike in that all are
eukaryotic
Which of the following are structures that protists utilize to swim?
flagella & cilia
Select all types of cell surfaces found in protists.
glass silica shell, plasma mem, extracellular matrix
Which of the following is NOT matched correctly regarding the type of endosymbiosis that lead to the acquisition of chloroplasts in algae?
green algae: secondary endosymbiosis
The mechanisms of mitosis and cytokinesis most likely evolved ____.
in several steps
Endosymbiotic bacteria are bacteria that can
live within other cells and perform specific functions for their host cells.
Amoebas are surrounded only by their plasma
membrane
An organism that is able to use both autotrophy and heterotrophy in order to obtain organic nutrients is a(n)
mixotroph
Eukaryotic organisms that cannot be classified in the plant, animal, or fungal kingdoms are
protists
True or false: Asexual reproduction in protists involves mitosis, however, the process is often different than mitosis in multicellular animals.
true!
the microfossils that show internal membranes and thicker walls are
1.5 billion years old
What type of prokaryote might have formed endosymbiotic relationships with other larger bacteria, eventually evolving into a chloroplast?
A photosynthetic cyanobacterium
What evidence supports the hypothesis that mitosis and cytokinesis did not evolve all at once?
Different, or possibly intermediate mechanisms of mitosis are observed in fungi and in some groups of protist compared to animals and plants.
Which of the following is the primary benefit of sexual reproduction in eukaryotes?
It allows for genetic recombination, thereby generating genetic variation.
A mixotroph uses which of the following means to obtain nutrition?
Photoautotrophy and heterotrophy
Which of the following statements about the origin of chloroplasts in red, green and brown algae are true?
Red algae acquired their chloroplasts through primary endosymbiosis. Green algae acquired their chloroplasts through primary endosymbiosis. Brown algae acquired their chloroplasts through secondary endosymbiosis.
According to our current understanding, stramenopiles and alveolates are members of the supergroup
SAR
Choose the 5 main supergroups of protists, according to our current understanding of protist phylogeny.
SAR Opisthokonta Archaeplastida Excavata Amoebozoa
How are the members of Protists related and what is the implication of their relationship for their grouping in the kingdom Protista?
They are only distantly related; grouping is artificial
In protists, a cyst is ____.
a life stage that can remain dormant during periods of unfavorable environmental conditions
Many different nutritional strategies are found in protists; they can be phagotrophs (ingest particles), ___ (ingest soluble nutrients), phototrophs, or ____ (both hetero- and phototrophs).
osmotrophs, mixotrophs
Which of the following are nutritional strategies found in Protista?
phototrophs, phagotrophs, mixotrophs
The grouping of protists into the kingdom Protista is
polyphyletic
Choose the three groups of protists that have true, if simple, multicellularity.
red, green, and brown algae
The process in which a eukaryotic host cell engulfs but does not consume another eukaryotic cell that possesses primary chloroplasts is ______ endosymbiosis
secondary
The process in which a eukaryotic host cell ingests and retains another type of eukaryotic cell is ____.
secondary endosymbiosis