Chapter 28 Protists
What characteristics do eukaryotes have that prokaryotes lack?
A cytoskeleton Organelles A nuclear envelope
Eukaryotes are distinguished from prokaryotes by the presence of which of the following?
A cytoskeleton and compartmentalization, which includes a nuclear envelope and organelles
Which of the following defines a cyst in protists?
A life stage that can remain dormant during periods of unfavorable environmental conditions
What type of prokaryote might have formed endosymbiotic relationships with other larger bacteria, eventually evolving into a chloroplast?
A photosynthetic bacterium
The genome of a mitochondrion is typically composed of which of the following?
A single, circular, closed molecule of DNA, similar to that in bacteria
Which of the following describes cysts in protists
Aids a parasite in the survival of the host's digestive tract A dormant cell with a resistant outer covering Helps protists over winter
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 likely led to the evolution of eukaryotes from early prokaryotic organisms?
An increase in membrane flexibility, allowing for one cell to engulf another The loss of a rigid cell wall, allowing membranes to fold inward
six supergroups are
Archaeplastida Amoebozoa Chromalveolata Excavata Ophisthokonta Rhizaria
Which of the following is the best definition of endosymbiotic bacteria?
Bacteria that live within other cells and perform specific functions for their host cells
How do mitochondria and chloroplasts replicate?
Binary fission
Which of the following describes mitosis?
Chromosomes are separated into two daughter cells.
During cell division, the process of cytokinesis involves the division of which of the following into two daughter cells?
Cytoplasm
Infoldings of the prokaryotic plasma membrane gave rise to the endomembrane system that includes which of the following?
Endoplasmic reticulum (ER), and nuclear envelope
Select all evolutionary mechanisms that were important in the early evolution of eukaryotes.
Engulfing other cells Horizontal gene transfer
Protists are alike in that all can be described which of the following?
Eukaryotic
Select all types of cell surfaces found in protists.
Extracellular matrix Glassy silica shell Plasma membrane
The nucleus and the ER of eukaryotes are thought to have evolved how?
From infoldings of the plasma membrane
Which of the following statements about the origin of chloroplasts in red, green and brown algae is true?
Green algae acquired their chloroplasts through primary endosymbiosis. Brown algae acquired their chloroplasts through secondary endosymbiosis. Red algae acquired their chloroplasts through primary endosymbiosis.
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
Which of the following is an advantage of multicellularity?
It fostered the specialization of cells.
The theory of endosymbiosis was originally proposed by Mereschkowsky and found widespread support after it was championed by BLANK in the 1970s.
Lynn Margulis
Which scientist championed the endosymiotic theory for the origin of organelles in eukaryotes in the 1970s?
Lynn Margulis
An innovation that occurred early in protist evolutionary history was endosymbiotic bacterial cells giving rise to BLANK organelles found in modern protists.
Mitochondria and chloroplast
Select all lines of evidence that support the endosymbiotic theory.
Mitochondria and chloroplasts divide by binary fission. Mitochondria and chloroplasts have smaller ribosomes than eukaryotes. Mitochondria and chloroplasts have their own circular DNA.
Select all lines of evidence that the ancestor of Giardia intestinalis was aerobic.
Mitochondrial genes are found in its nucleus. Giardia cells contain degenerate mitochondria.
Which of the following is the best description of how many times multicellularity has arisen?
Multiple times among the eukaryotes
Which of the following are nutritional strategies found in protists?
Phagotrophs Phototrophs Mixotrophs
Which of the following defines chloroplasts?
Photosynthetic organelles found in plants and algae
Which of the following are important features of eukaryotes that distinguish them from prokaryotes?
Presence of organelles such as mitochondria and chloroplasts Presence of a cytoskeleton Presence of a nucleus
Which of the following describes the ribosomes in mitochondria?
They are similar to bacterial ribosomes.
Select features common to members of the supergroup Excavata.
They are unicellular. They possess a feeding groove. They move using flagella.
What is the function of the undulating membranes in parabasalids?
They are used for locomotion.
Select all features of diplomonads.
They lack functional mitochondria. They have two nuclei. They are unicellular.
Select all true statements about protists.
They vary in the way they obtain nutrients. Most are microscopic, but some are large. Many are unicellular, but some are multicellular.
Entamoeba histolytica
amoebic dysentery
Mitochondria and chloroplasts contain their own DNA which is very similar in size and character to the DNA of
bacteria
Mitochondria and chloroplasts replicate by
binary fission
The photosynthetic organelles of plants and algae are called
chloroplast
Even though chloroplasts of different algae are not monophyletic, it is thought that all chloroplasts derived from a single line of
cyanobacteria
Many protists with delicate surfaces are capable of surviving unfavorable environmental conditions because they can form which of the following?
cyst
The process in which cytoplasm is divided into two daughter cells during cell division is called
cytokinesis
In early prokaryotes, the loss of a rigid cell wall and an increase in membrane flexibility likely led to the evolution of
eukaryotes
Select all structures used by protists for locomotion.
flagella cilia pseudopods
is a diplomonad parasite that can pass from human to human via contaminated water and causes diarrhea
giardia intestinalis
Some protists, such as amoebas, are surrounded only by their plasma membrane whereas others such as diatoms and foraminifera are surrounded by
glassy shells of silica
The earliest eukaryotic cells evolved through the transfer of genes across species boundaries, a process called
horizontal
During cell division, the separation of replicated chromosomes into two daughter cells is called
mitosis
Protists that are both phototrophic and heterotrophic are called
mixotrophs
Eukaryotes differ from prokaryotes in many ways; for example, eukaryotes possess compartmentalization in the form of such as mitochondria and chloroplasts.
organelles
The significance of endosymbiosis in protist evolution centers on the origin of complex
organelles
Euglenozoans exhibit extreme flexibility; they change shape while swimming thanks to strips of
protein encircling their cells rather than a cell wall.
Eukaryotic organisms that cannot be classified in the plant, animal, or fungal kingdoms are
protists
The RNA transcripts produced by mitochondria and chloroplasts are translated by smaller
ribosomes which are very similar to those found in bacteria.
Mitochondria can synthesize proteins with their own
ribosomes which are very similar to those of bacteria in size and structure.
Protists can exhibit both
sexual asexual reproduction
Trypanosoma brucei
sleeping sickness
Protists were the first eukaryotes.
true
Trichomonas vaginalis
vaginitis and urethritis