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